Review
published: 19 February 2016
doi: 10.3389/frobt.2016.00003
Real virtuality: A Code of ethical 
Conduct. Recommendations for 
Good Scientific Practice and the 
Consumers of vR-Technology
Michael Madary* and Thomas K. Metzinger
Johannes Gutenberg – Universität Mainz, Mainz, Germany
The goal of this article is to present a first list of ethical concerns that may arise from 
research and personal use of virtual reality (VR) and related technology, and to offer 
concrete recommendations for minimizing those risks. Many of the recommendations 
call for focused research initiatives. In the first part of the article, we discuss the relevant 
evidence from psychology that motivates our concerns. In Section “Plasticity in the 
Human Mind,” we cover some of the main results suggesting that one’s environment 
can influence one’s psychological states, as well as recent work on inducing illusions of 
Edited by: embodiment. Then, in Section “Illusions of Embodiment and Their Lasting Effect,” we go 
Nadia Magnenat Thalmann, on to discuss recent evidence indicating that immersion in VR can have psychological 
University of Geneva, Switzerland
effects that last after leaving the virtual environment. In the second part of the article, we 
Reviewed by: 
Jean-Marie Normand, turn to the risks and recommendations. We begin, in Section “The Research Ethics of 
Ecole Centrale de Nantes, France VR,” with the research ethics of VR, covering six main topics: the limits of experimental 
HyungSeok Kim, environments, informed consent, clinical risks, dual-use, online research, and a general 
Konkuk University, South Korea 
Roland Blach, point about the limitations of a code of conduct for research. Then, in Section “Risks for 
Fraunhofer Institut für Individuals and Society,” we turn to the risks of VR for the general public, covering four 
Arbeitswirtschaft und Organisation, 
Germany main topics: long-term immersion, neglect of the social and physical environment, risky 
*Correspondence: content, and privacy. We offer concrete recommendations for each of these 10 topics, 
Michael Madary summarized in Table 1.
madary@uni-mainz.de
Keywords: ethics, virtual reality, augmented reality, substitutional reality, depersonalization disorder, derealization, 
Specialty section: informed consent, dual use
This article was submitted to 
Virtual Environments, 
a section of the journal PReLiMiNARY ReMARKS
Frontiers in Robotics and AI
Received: 05 December 2015 Media reports indicate that virtual reality (VR) headsets will be commercially available in early 2016, 
Accepted: 08 February 2016 or shortly thereafter, with offerings from, for example, Facebook (Oculus), HTC and Valve (Vive) 
Published: 19 February 2016 Microsoft (HoloLens), and Sony (Morpheus). There has been a good bit of attention devoted to the 
Citation: exciting possibilities that this new technology and the research behind it have to offer, but there has 
Madary M and Metzinger TK (2016) been less attention devoted to novel ethical issues or the risks and dangers that are foreseeable with the 
Real Virtuality: A Code of Ethical widespread use of VR. Here, we wish to list some of the ethical issues, present a first, non-exhaustive 
Conduct. Recommendations for list of those risks, and offer concrete recommendations for minimizing them. Of course, all this takes 
Good Scientific Practice and the 
Consumers of VR-Technology. place in a wider sociocultural context: VR is a technology, and technologies change the objective 
Front. Robot. AI 3:3. world. Objective changes are subjectively perceived, and may lead to correlated shifts in value judg-
doi: 10.3389/frobt.2016.00003 ments. VR technology will eventually change not only our general image of humanity but also our 
Frontiers in Robotics and AI | www.frontiersin.org 1 February 2016 | Volume 3 | Article 3
Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
understanding of deeply entrenched notions, such as “conscious when merely using the device for 3D viewing. Many of our points 
experience,” “selfhood,” “authenticity,” or “realness.” In addition, are also relevant for other types of VR hardware, such as CAVE 
it will transform the structure of our life-world, bringing about projection. One central area of concern has to do with illusions of 
entirely novel forms of everyday social interactions and changing embodiment, in which one has the feeling of being embodied other 
the very relationship we have to our own minds. In short, there than in one’s actual physical body (Petkova and Ehrsson, 2008; 
will be a complex and dynamic interaction between “normality” Slater et al., 2010). In VR, for instance, one might have the illusion 
(in the descriptive sense) and “normalization” (in the normative of being embodied in an avatar that looks just like one’s physical 
sense), and it is hard to predict where the overall process will lead body. Or one might have the illusion of being embodied in an 
us (Metzinger and Hildt, 2011). avatar of a different size, age, or skin color. In all of these cases, 
Before beginning, we should quickly situate this article within insight into the illusory nature of the overall state is preserved. 
the larger field of the philosophy of technology. Brey (2010) has The fact that VR technology can induce illusions of embodiment 
offered a helpful taxonomy dividing the philosophy of technol- is one of the main motivations behind our investigation into the 
ogy into the classical works from the mid-twentieth century, new risks generated by using VR by researchers and by the general 
on the one hand, and more recent developments that follow an public. Traditional paradigms in experimental psychology cannot 
“empirical turn” by focusing on the nature of particular emerging induce these strong illusions. Similarly, watching a film or playing 
technologies, on the other hand. We intend the present article to a non-immersive video game cannot create the strong illusion of 
be a contribution to the latter kind of philosophy of technology. In owning and controlling a body that is not your own. Although 
particular, we are investigating foundational issues in the applied our main focus will be on VR (see Figure 1), many of the risks and 
ethics of VR, with a heavy emphasis on recent empirical results. recommendations can be extended to augmented reality (Azuma, 
Both authors have been participants in the collaborative project 1997; Metz, 2012; Huang et  al., 2013 and substitutional reality 
Virtual Embodiment and Robotic Re-Embodiment (VERE), a (Suzuki et al., 2012; Fan et al., 2013). In augmented reality (AR, 
5-year research program funded by the European Commission.1 see Figure 2), one experiences virtual elements intermixed with 
Despite this explicit focus, we do not mean to imply that the one’s actual physical environment.
issues investigated here will not find fruitful application to themes Following Milgram and colleagues (Milgram and Kishino, 
from classical twentieth century philosophy of technology (see 1994; Milgram and Colquhoun, 1999), it may be helpful here 
Franssen et al., 2009). Consider, for instance, Martin Heidegger’s to consider augmented reality along the Reality–Virtuality 
influential treatment of the way in which modern technology Continuum. The real environment is located at one extreme of 
distorts our metaphysics of the natural world (Heidegger, 1977; the continuum and an entirely virtual environment is located at 
also Borgmann, 1984), or Herbert Marcuse’s prescient account the other extreme. Displays can be placed along the continuum 
of industrial society’s ongoing creation of false needs that under- according to whether they primarily represent the real environ-
mine our capacities for individuality (Marcuse, 1964). As should ment while including some virtual elements (augmented reality) 
become clear from the examples below, immersive VR introduces or they primarily represent a virtual environment while including 
new and dramatic ways of disrupting our relationship to the natu- some real elements (augmented virtuality). Much of the following 
ral world (see Neglect of Others and the Physical Environment). discussion will focus on entirely virtual environments, but readers 
Likewise, the newly created “need” to interact using social media should keep in mind that many of the concerns raised will also 
will become even more psychologically ingrained as the interac- apply to environments all along the Reality–Virtuality Continuum.
tions begin to take place while we are embodied in virtual spaces It is foreseeable that there will be ever new extensions and 
(see The Effects of Long-Term Immersion and O’Brolcháin et al., special cases of VR. We return to this theme with some philo-
2016). In sum, the fact that connections with classical philosophy sophical remarks at the end of the article. For now, let us at least 
of technology will remain largely implicit in this article should note that the very distinction between the real and the virtual is 
not be taken to suggest that they are not of great importance. ripe for further philosophical investigation. One example of such 
The main focus will be on immersive VR, in which subjects a special, recent extension of VR that does not in itself form a 
use a head-mounted display (HMD) to create the feeling of being distinct new category is “substitutional reality” (SR, see Figure 3), 
within a virtual environment. Although our main topic involves in which an omni-directional video feed gives one the illusion of 
the experience of immersion, some of the concerns raised, such being in a different location in space and/or time, and insight may 
as neglect of the physical environment (see Neglect of Others and not be preserved. Readers should keep in mind that VR headsets 
the Physical Environment), can be applied to extended use of an will likely enable users to toggle between virtual, augmented, and 
HMD even when users do not experience immersion such as substitutional reality, and to adjust one’s location on the Reality–
Virtuality Continuum, thus somewhat blurring the boundaries 
between kinds of immersive environments.
1 The project, as well as the current publication, is funded under the EU 7th We divide our discussion into two main areas. First, we will 
Framework Program, Future and Emerging Technologies (Grant 257695). VERE address the research ethics of VR. Then we will turn to issues aris-
aimed at dissolving the boundary between the human body and surrogate represen- ing with the use of VR by the general public for entertainment and 
tations in immersive virtual reality and physical reality, giving people the illusion other purposes. To be clear upfront, we are not calling for general 
that their surrogate representation is their own body. See http://www.vereproject.
eu/ for more. We thank members of the VERE consortium for discussing many of restrictions on an individual’s liberty to spend time (and money) 
the issues in this article during our VERE Ethics Workshops in February 2013 and in VR. In open democratic societies, such regulations must be 
September 2015. based on rational arguments and available empirical evidence, 
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
FiGURe 1 | illusory ownership of an avatar in virtual reality. Here, a subject is shown wearing a head-mounted display and a body tracking suit. The subject can see 
his avatar in VR moving in synchrony with his own movements in a virtual mirror. In this case, the avatar is designed to replicate Sigmund Freud in order to enable subjects 
to counsel themselves. Thus, creating what Freud may have called an instance of avatar-introjection! (Image used with kind permission from Osimo et al., 2015.)
FiGURe 2 | An augmented reality hand illusion. Here, augmented reality is used to show the subject a virtual hand in a biologically realistic location relative to his 
own body. This case differs from virtual reality due to the fact that the subject sees the virtual hand embedded in his own physical environment rather than in an 
entirely virtual environment (image used with kind permission from Keisuke Suzuki).
FiGURe 3 | immersion in the past using substitutional reality. In this example, substitutional reality is used to allow switching between a live view of the scene 
and a panoramic recording of that scene from the past. Note that SR could also be used to provide live (or recorded) panoramic input from a distant location, 
creating the illusion that one is “present” somewhere else (image used with kind permission from Anil Seth).
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
and they should be guided by a general principle of liberalism: underlying the neurally realized part of the human self-model 
in principle, the individual citizen’s freedom and autonomy in [for example, of the body model in our brain, e.g., Metzinger 
dealing with their own brain and in choosing their own desired (2003), p. 355] that are largely genetically determined. However, 
states of mind (including all of their phenomenal and cognitive we also want to point out that human beings possess a large 
properties) should be maximized. As a matter of fact, we would number of epigenetic traits, that is, a stably heritable phenotype 
even argue for a constitutional right to mental self-determination resulting from changes in a chromosome without alterations in 
(Bublitz and Merkel, 2014), somewhat limiting the authority the DNA sequence.
of the government, because the above-mentioned values of 
individual freedom and mental autonomy seem to be absolutely 
fundamental to the idea of a liberal democracy involving a Context-Sensitivity All the Way Down
separation of powers. However, once such a general principle has The way in which our behavior is sensitive to environmental 
been clearly stated, the much more interesting and demanding features is especially relevant here due to the fact that VR intro-
task lies in helping individuals exercise this freedom in an intel- duces a completely new type of environment, a new cognitive and 
ligent way, in order to minimize potential adverse effects and the cultural niche, which we are now constructing for ourselves as a 
overall psychosocial cost to society as a whole (Metzinger, 2009a; species.
Metzinger and Hildt, 2011). New technologies like VR open a vast 
space of potential actions. This space has to be constrained in a It is not excluded that extended interactions with VR 
rational and evidence-based manner. environments may lead to more fundamental changes, 
Similarly, we fully support ongoing research using VR – indeed, not only on a psychological, but also on a biological level.
we argue below that there are ethical demands to do more 
research using it, research that is motivated in part with the goal Some of the most famous experiments in psychology reveal 
of mitigating harm for the general public. But we do think that it the context sensitivity of human behavior. These include the 
is prudent to anticipate risks and we wish to spread awareness of Stanford Prison Experiment, in which normal subjects playing 
how possibly to avoid, or at least minimize, those risks.2 Before roles as either prison guards or inmates began to show patho-
entering into the concrete details, we are going to make the case logical behavioral traits (Haney et al., 1973), Milgram’s obedi-
for being especially concerned about VR technology in contrast, ence experiments, in which subjects obeyed orders that they 
say, to television or non-immersive video games. We do so in believed to cause serious pain and be immoral (Milgram, 1974), 
two steps. First, in Section “Plasticity in the Human Mind,” we and Asch’s conformity experiments, in which subjects gave obvi-
cover some of the relevant discoveries from psychology in the ously incorrect answers to questions after hearing confederates, 
past decades, including the scientific foundation for illusions of all give the same incorrect answers (Asch, 1951). For a more 
embodiment. Then in Section “Illusions of Embodiment and recent result showing the unconscious impact of environment 
Their Lasting Effect,” we cover the more recent experimental on behavior, the amount of money placed in a collection box 
work that has begun to reveal the lasting psychological effects of for drinks in a university break room was measured under a 
these illusions. Then in Section “Recommendations for the Use condition in which the image of a pair of eyes was posted above 
of VR by Researchers and Consumers,” we will cover the research the collection box. With the eyes “watching,” coffee drinkers 
ethics of VR followed by risks for the general public. placed three times as much money in the box compared to the control condition with no eyes (Bateson et  al., 2006). Effects 
like this one may be particularly relevant in VR, because the 
Plasticity in the Human Mind subjective experience of presence and being there is not only 
One central result of modern experimental psychology is that determined by functional factors like the number and fidelity 
human behavior can be strongly influenced by external factors of sensory input and output channels, the ability to modify the 
while the agent is totally unaware of this influence. Behavior is virtual environment, but also, importantly, the level of social 
context sensitive and the mind is plastic, which is to say that interactivity, for example, in terms of actually being recognized 
it is capable of being continuously shaped and re-shaped by a as an existing person by others in the virtual world (Heeter, 1992; 
host of causal factors. These results, some of which we present Metzinger, 2003). As investigations into VR have interestingly 
below, suggest that our environment, including technology and shown, a phenomenal reality as such becomes more real  –  in 
other humans, has an unconscious influence on our behavior. terms of the subjective experience of presence – as more agents 
Note that the results do not conflict with the manifest fact that recognizing one and interacting with one are contained in this 
most of us have relatively stable character traits over time. After reality. Phenomenologically, ongoing social cognition enhances 
all, most of us spend our time in relatively stable environments. both this reality and the self in their degree of “realness.” This 
And there may be many aspects of the functional architecture principle will also hold if the subjective experience of ongoing 
social cognition is of a hallucinatory nature.
2 Behr et  al. (2005) have addressed similar themes about practical issues in VR 
research and applications. Here, we wish to address concerns that go beyond their Potential for Deep Behavioral Manipulation
initial treatment of the topic. More recently, O’Brolcháin et al. (2016) have covered 
ways in which the conjunction of VR with social networks might raise threats Whether physical or virtual, human behavior is situated and 
to privacy and autonomy. We will engage with some of their concerns at various socially contextualized, and we are often unaware of the causal 
points below. impact this fact has on learning mechanisms as well as on 
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
occurrent behavior. It is plausible to assume that this will be true 2009; Windt, 2010; Metzinger, 2013a,b); and in some configura-
of novel media environments as well. Importantly, unlike other tions (e.g., “being one with the world”), there is also a maximal 
forms of media, VR can create a situation in which the user’s entire UI, likely constituted by the most general phenomenal property 
environment is determined by the creators of the virtual world, available, namely, the integrated nature of phenomenality per se 
including “social hallucinations” induced by advanced avatar (Metzinger, 2013a,b).
technology. Unlike physical environments, virtual environments 
can be modified quickly and easily with the goal of influencing VR technology directly targets the mechanism by which 
behavior. human beings phenomenologically identify with the 
content of their self-model.
The comprehensive character of VR plus the potential 
for the global control of experiential content introduces The rubber hand illusion is a simple localized illusion of 
opportunities for new and especially powerful forms of embodiment that can be induced by having subjects look 
both mental and behavioral manipulation, especially at a visually realistic rubber hand in a biologically realistic 
when commercial, political, religious, or governmental position (Botvinick and Cohen, 1998; Tsakiris and Haggard, 
interests are behind the creation and maintenance of the 2005). When the rubber hand is stroked synchronously with 
virtual worlds. the subject’s physical hand (which is hidden from view), 
subjects experience the rubber hand as their own.3 While the 
However, the plasticity of the mind is not limited to behavioral rubber hand can be used to create a partial illusion of embodi-
traits. Illusions of embodiment are possible because the mind is ment, the same basic idea can be used to create the full-body 
plastic to such a degree that it can misrepresent its own embodi- illusion, on a global level. Subjects look through goggles 
ment. To be clear, illusions of embodiment can arise from normal through which they see a live video feed of their own bodies 
brain activity alone, and need not imply changes in underlying (or of a virtual body) located a short distance in front of their 
neural structure. Such illusions occur naturally in dreams, actual location. When they see their bodies being stroked on 
phantom limb experiences, out-of-body experiences, and Body the back, and feel themselves being stroked at the same time, 
Integrity Identity Disorder (Brugger et  al., 2000; Metzinger, subjects sometimes feel as if the body that they see in front of 
2009b; Hilti et  al., 2013; Ananthaswamy, 2015; Windt, 2015), them is their own (Lenggenhager et al., 2007; see Figure 4). 
and they sometimes include a shift in what has been termed the This illusion is much weaker and more fragile than the RHI, 
phenomenal “unit of identification” in consciousness research but it has given us valuable new insights into the bottom-up 
(UI; Metzinger, 2013a,b), the conscious content that we currently construction of our conscious, bodily self-model in the brain 
experience as “ourselves” (please note that in the current paper (Metzinger, 2014). In more recent work, Maselli and Slater 
“UI” does not refer to “user interface,” but always to the specific (2013) have found that tactile feedback is not required for an 
experiential content of “selfhood,” as explained below). This may illusion of embodiment. They found that a virtual arm with a 
be the deepest theoretical reason why we should be cautious realistic appearance co-located with the subject’s actual arm 
about the psychological effects of applied VR: this technology is sufficient to induce the illusion of ownership of the virtual 
is unique in beginning to target and manipulate the UI in our arm. In addition to visual and tactile signals, recent work 
brain itself. suggests that manipulations of interoceptive signals, such as 
heartbeat, can also influence our experience of embodiment 
Direct UI-Manipulation (Aspell et al., 2013; Seth, 2013).
The UI is the form of experiential content that gives rise to The results sketched in these three sections reveal not only 
autophenomenological reports of the type “I am this!” For categories of risks but also three ways in which the human mind 
every self-conscious system, there exists a phenomenal unit of is plastic. First, there is “context-sensitivity all the way down,” 
identification, such that the system possesses a single, conscious which may involve hitherto unknown kinds of epigenetic trait 
model of reality; the UI is a part of this model; at any given formation in new environments. Second, there is evidence that 
point in time, the UI can be characterized by a specific and behavior can be strongly influenced by environment and context, 
determinate representational content, which in turn constitutes and in a deep way. Third, illusions of embodiment can be induced 
the system’s phenomenal self-model (PSM, Metzinger, 2003) at fairly easily in the laboratory, directly targeting the human UI 
t. Please note how the UI does not have to be identical with itself. These results can be taken together as empirical premises 
the content of the conscious body image or a region within it for an argument stating not only that there may be unexpected 
(like a fictitious point behind the eyes). For example, the UI psychological risks if illusions of embodiment are misused, 
can be moved out of and behind the head as phenomenally or used recklessly, but that, if we are interested in minimizing 
experienced in a repeatable and controllable fashion by direct potential damage and future psychosocial costs, these risks are 
electrical stimulation while preserving the visual first-person themselves ethically relevant. In the following section, we review 
perspective with its origin behind the eyes (de Ridder et  al., initial evidence that connects the three strands of evidence that 
2007). For human beings, the UI is dynamic and can be highly 
variable. There exists a minimal UI, which likely is constituted 3 For a version of this illusion using a virtual hand in augmented reality (rather than 
by pure spatiotemporal self-location (Blanke and Metzinger, a rubber hand), see Figure 2 above.
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
FiGURe 4 | Creating a whole-body analog of the rubber-hand illusion. (A) Participant (dark blue trousers) sees through a HMD his own virtual body (light blue 
trousers) in 3D, standing 2 m in front of him and being stroked synchronously or asynchronously at the participant’s back. In other conditions, the participant sees 
either (B) a virtual fake body (light red trousers) or (C) a virtual non-corporeal object (light gray) being stroked synchronously or asynchronously at the back. Dark 
colors indicate the actual location of the physical body or object, whereas light colors represent the virtual body or object seen on the HMD. (Image used with kind 
permission from M. Boyer.).
we have just presented. That is, we review initial evidence that risks of existing media technology for the general public. A first 
illusions of embodiment can be combined with a change in envi- important result from VR research involves what is known as 
ronment and context in order to bring about lasting psychological the virtual pit (Meehan et al., 2002). Subjects are given a HMD 
effects in subjects. that immerses them in a virtual environment in which they are 
standing at the edge of a deep pit. In one kind of experiment 
illusions of embodiment and Their  involving the pit, they are instructed to lean over the edge and 
Lasting effect drop a beanbag onto a target at the bottom. In order to enhance 
In the last several years, a number of studies have found a the illusion of standing at the edge, the subject stands on the ledge 
psychological influence on subjects while immersed in a virtual of a wooden platform in the lab that is only 1.5″ from the ground. 
environment. These studies suggest that VR poses risks that Despite their belief that they were in no danger because the pit was 
are novel, that go beyond the risks of traditional psychological “only” virtual, subjects nonetheless show increased signs of stress 
experiments in isolated environments, and that go beyond the through increases in heart rate and skin conductance (ibid.). In a 
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
variation of the virtual pit, subjects may be told to walk across the ReCOMMeNDATiONS FOR THe USe OF 
pit over a virtual beam. In the lab, a real wooden beam is placed vR BY ReSeARCHeRS AND CONSUMeRS
where subjects see the virtual beam. As one might expect, this 
version of the pit also elicits strong feelings of stress and fear.4 With the results from the first section of the paper in mind as 
More recently, an experiment reproducing the famous Milgram illustrative examples, we now move on to make concrete recom-
obedience experiments in VR found that subjects reacted as if the mendations for VR in both scientific research (see The Research 
shocks they administered were real, despite believing that they Ethics of VR) and consumer applications (see Risks for Individuals 
were merely virtual (Slater et al., 2006). and Society). Our main recommendations are italicized and listed 
In addition to a strong emotional response from immersion, together in Table 1.
there is evidence that experiences in VR can also influence 
behavioral responses. One example of a behavioral influence 
from VR has been named the Proteus Effect by Nick Yee and The Research ethics of vR
Jeremy Bailenson. This effect occurs when subjects “conform In this section, we cover questions about the ethics of conducting 
to the behavior that they believe others would expect them to research either on VR, or, perhaps more interestingly, research 
have” based on the appearance of their avatar (Yee and Bailenson, using VR as a tool. For example, it is plausible to assume that in 
2007, p. 274; Kilteni et al., 2013). They found, for example, that the future there will be many experiments combining real-time 
subjects embodied in a taller avatar negotiated more aggressively fMRI and VR or ones using animal subjects in VR (Normand 
than subjects in a shorter avatar (ibid.). Changes in behavior et al., 2012), which are not only about understanding or improv-
while in the virtual environment are of ethical concern, since ing VR itself but only use it a research tool. To begin with a short 
such behavior can have serious implications for our non-virtual example, Behr et al. (2005) have covered the research ethics of VR 
physical lives – for example, as financial transactions take place from a practical perspective, emphasizing that the risk of motion 
in a non-physical environment (Madary, 2014). sickness must be minimized and that researchers ought to assist 
But perhaps even more concerning for our purposes is evi- subjects as they leave the virtual environment and readjust to the 
dence that behavior while in the virtual environment can have a real world. In this part of the article, we indicate new issues in the 
lasting psychological impact after subjects return to the physical research ethics of VR that were not covered in Behr et al.’s initial 
world. Hershfield et al. (2011) found that subjects embodying treatment. In particular, we will raise the following six issues:
avatars that look like aged versions of themselves show a ten- • the limits of experimental environments,
dency to allocate more money for their retirement after leaving • informed consent with regard to the lasting psychological 
the virtual environment. Rosenberg et al. (2013) had subjects effects of VR,
perform tasks in a virtual city. Subjects were allowed to fly • risks associated with clinical applications of VR,
through the city either using a helicopter or by their own body • the possibility of using results of VR research for malicious 
movements, like Superman. They found that subjects given purposes (dual use),
the superpower were more likely to show altruistic behavior • online research using VR, and
afterwards – they were more likely to help an experimenter pick • a general point about the inherent limitations of a code of 
up spilled pens. Yoon and Vargas (2014) found a similar result, conduct for research.
although not using fully immersive VR. They had subjects play For each of these issues, we offer concrete recommendations 
a video game as either a superhero, a supervillain, or a neutral for researchers using VR as well as ethics committees charged 
control avatar. After playing the game, subjects were given a with evaluating the permissibility of particular experimental 
tasting task that they were told was unrelated to the gaming paradigms using VR.
experiment. Subjects were given either chocolate or chili sauce 
to taste, and then told to measure out the amount of food for the Ethical Experimentation
subsequent subject to taste. Those who played as heroes poured What are the limits to what we can do ethically as experiments in 
out more chocolate, while those who played as villains poured VR? We recommend, at the very least, that researchers ought to 
out more chili. follow the principle of non-maleficence: do no harm. This princi-
The psychological impact of immersive VR has also been ple is a central component of research ethics on human subjects 
explored in a beneficent application. Peck et al. (2013) gave sub- where it is often discussed with the accompanying principle of 
jects an implicit racial bias test at least 3 days before immersion beneficence: maximize well-being for the subjects. Note how such 
and then immediately after the immersion. In the experiment, a principle applies to all sentient beings capable of suffering, like 
subjects were embodied in an avatar with either light skin, dark non-human animals or even potential artificial subjects of experi-
skin, purple skin, or they were immersed in the virtual world with ence in the future (Althaus et  al., 2015, p. 10). We will return 
no body. They found that subjects who were embodied in the to the principle of beneficence in VR in the following section. 
dark-skinned avatar showed a decrease in implicit racial bias, at The principle of non-maleficence can be found in the codes of 
least temporarily. ethical conduct for both the American Psychological Association 
(General Principle A)5 as well as in the British Psychological 
4 For some nice anecdotal accounts of experiences with the virtual pit, see Blascovich 
and Bailenson, 2011: 38-42. 5 http://www.apa.org/ethics/code/
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
Society (Principle 2.4). The British Psychological Society offers environments. The principle of non-maleficence should be applied 
the following recommendation: in the sense that experiments should not be conducted if the 
outcome involves foreseeable harm to the subjects. On the other 
Harm to research participants must be avoided. Where hand, the same principle implies a sustained striving for rational, 
risks arise as an unavoidable and integral element of evidence-based minimization of risks in the more distant future. 
the research, robust risk assessment and management We, therefore, suggest that careful experiments designed with the 
protocols should be developed and complied with. beneficent intention of discovering the psychological impact of 
Normally, the risk of harm must be no greater than that immersion in VR are ethically permissible.
encountered in ordinary life, i.e., participants should not In order to adhere to the principle of non-maleficence, 
be exposed to risks greater than or additional to those to researchers (and ethics committees) will need to utilize their 
which they are exposed in their normal lifestyles (The knowledge of experimental psychology as well as their knowl-
British Psychological Society, 2014, p. 11). edge of results specific to VR. The kinds of results sketched 
in Sections “Plasticity in the Human Mind” and “Illusions of 
Following this recommendation in the case of VR might Embodiment and Their Lasting Effect” will be directly relevant 
raise some novel challenges due to the entirely new nature of the for evaluating whether a line of experimentation violates 
technology. For instance, a well-known domain of application for non-maleficence. Similarly, the selection of subjects for VR 
the principle of non-maleficence has been in clinical trials for experiments must be done with special care. New methods of 
new pharmacological agents. Although this domain of research prescreening for individuals with high risk factors must be incre-
ethics still faces important and controversial issues (Wendler, mentally developed, and funding for the development of such 
2012), thinkers in the debate can avail themselves of the history of new methodologies needs to be allocated. We, therefore, urge 
medical technology. In many cases, precedents can be quoted. In careful screening of subjects to minimize the risks of aggravating 
the case of VR, there is yet no history that we can use as a source an existing psychological disorder or an undetected psychiatric 
for insight. On the contrary, what is needed is a rational, ethically vulnerability (Rizzo et al., 1998; Gregg and Tarrier, 2007). Many 
sound process of precedence-setting. experiments using VR currently seek to treat existing psychiat-
In its general form, the principle of non-maleficence for VR ric disorders. The screening process for such experiments has 
can be expressed as follows: the goal of selecting subjects who exhibit signs and symptoms of 
an existing condition. The screening process should also include 
No experiment should be conducted using virtual reality exclusion criteria specific to possible risks posed by VR. Ideally, 
with the foreseeable consequence that it will cause serious the VR research community will seek to establish an empirically 
or lasting harm to a subject. motivated standard set of exclusion criteria. As we will discuss 
in Section “The Effects of Long-Term Immersion” below, of 
Although recommending adherence to this principle is noth- particular concern are vulnerabilities to disorders that could 
ing new, implementing this principle in VR laboratories may be potentially become aggravated by prolonged immersion and illu-
challenging for the following reason. Attempts to apply non- sions of embodiment, such as Depersonalization/Derealization 
maleficence in VR can encounter a dilemma of sorts. On the one Disorder (DDD; see American Psychiatric Association (2013), 
hand, a goal of the research ought to be, as we suggest below, to DSM-5: 300.14). Standard exclusion criteria may involve, for 
gain a better understanding of the risks posed for individuals instance, scoring above a particular threshold on scales testing 
using VR. For instance, does the duration of immersion pose for dissociative experiences (Bernstein and Putnam, 1986) or 
a greater risk for the user? Might some virtual environments depersonalization (Sierra and Berrios, 2000). Of course, there 
be more psychologically disturbing than others? VR research may be cases in which experimenters seek to include subjects 
should seek to answer these and similar questions. In particular, with experiences of dissociation in order to investigate ways 
open-ended longitudinal studies will be necessary to assess the in which VR might be used to treat the underlying conditions, 
risk of long-term usage for the general population, just like with such as treating post-traumatic stress disorder (PTSD) through 
new substances for pharmaceutical cognitive enhancement exposure therapy in VR (Botella et al., 2015). In those special 
or medical treatments more generally. On the other hand, it cases, it is important to implement alternative exclusion criteria, 
is difficult to assess these risks without running experiments such as Rothbaum et al. (2014), who excluded subjects with a 
that generate those possible risks, thus raising worries about history of psychosis, bipolar disorder, and suicide risk.
non-maleficence.
A strict adherence to non-maleficence would require avoid-
ing all experiments using virtual environments for which the Informed Consent
risk is unknown. We suggest that this strict interpretation of The results presented above clearly suggest that VR experiences 
non-maleficence is not optimal, because substantial ethical can have lasting psychological impact. This new knowledge about 
assessments should always be evidence-based and necessarily the lasting influence of experiences in VR must not be withheld 
involve the investigation of greater time-windows and larger from subjects in new VR experiments.
populations. VR researchers could and should provide a valuable 
service by informing the public and policy makers of the possible We recommend that informed consent for VR experi-
risks of spending large amounts of time in unregulated virtual ments ought to include an explicit statement to the effect 
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
that immersive VR can have lasting behavioral influences of the research, rather than motivated by false hope or even 
on subjects, and that some of these risks may be presently desperation.
unknown.
VR researchers aiming at new clinical applications should 
Subjects should be made aware of this possibility out of respect therefore work slowly and carefully, in close collaboration 
for their autonomy (as included, for example, in the American with physicians who may be better situated to make 
Psychological Association General Principle D)6. That is, if an informed judgments about the suitability of particular 
experiment might alter their behavior without their awareness patients for new trials.
of this alteration, then such an experiment could be seen as a 
threat to the autonomy of the subject. A reasonable way to Therapeutic and clinical applications should be investigated 
preserve autonomy, we suggest, is simply to inform subjects of only in the presence of certified medical personnel.
possible lasting effects. Please again note the principled problem Another relevant concern here is the way in which the general 
that research animals are not able to give informed consent, their public keeps informed of new developments in science through the 
interest needs to be represented by humans. Also note that we popular media. Members of the general public with less interest in 
are not suggesting that subjects ought to be informed about the science may have a more difficult time gleaning scientific knowl-
particular effects that are being investigated in the experiment. edge from the media than those with more interest (Takahashi 
Thus, our recommendation should not raise the concern that and Tandoc, 2015). When considering their responsibility as 
informing subjects may compromise researchers’ abilities to test scientists to communicate new results to the public (Fischhoff, 
for particular behavioral effects. 2013; Kueffer and Larson, 2014), VR researchers working in clini-
cal applications must be careful to avoid language that might give 
Practical Applications: False Hope and Beneficence false hope to patients.
Another concern has to do with various applications of VR. One of We should also note here that there are other practical concerns 
many promising applications for VR research is in the treatment about the use of VR for medical interventions. For instance, once 
of disease, damage, and other health-related issues, especially the technology is available for patients to use, who will pay for 
mental health.7 For instance, researchers found that immersing it? Should medical insurance pay for HMDs and new software? 
burn victims in an icy virtual environment can mitigate their How do we achieve distributive justice and avoid a situation where 
experience of pain during medical procedures (Hoffman et al., only privileged members of society benefit from technological 
2011). Here, we wish to raise some concerns about applications of advances? We make no recommendation here, but flag this ques-
VR. The first concern is that patients may develop false hope with tion as something that needs to be considered by policy makers. 
regard to clinical applications of VR. The second concern is that Similarly, HMDs, CAVE immersive displays, and motion-tracking 
applications of VR may encounter a tension between beneficence technology may have to be reclassified as medical devices.
and autonomy. One risk when performing the research necessary for develop-
Patients may believe that treatment using VR is better than ing such applications is that the patients involved may develop 
traditional interventions merely due to the fact that it is a new a false sense of hope due to the non-traditional nature of the 
technology, or an experimental application of existing tech- intervention. As this kind of research progresses, scientists must 
nology. This sense of false hope is known as the “therapeutic continue to be honest with patients so as not to generate false 
misconception” in the literature on the ethics of clinical research hope. There is also an overlap between media ethics and the ethics 
(Appelbaum et al., 1987; Kass et al., 1996; Lidz and Appelbaum, of VR technology: a related example is that many of the early 
2002; Chen et  al., 2003). Researchers using VR for clinical experiments on full-body illusions (Ehrsson, 2007; Lenggenhager 
research must be aware of established techniques for combating et al., 2007) have been falsely overreported as creating full-blown 
the therapeutic misconception in their subjects. For example, “out-of-body experiences” (Metzinger, 2003, 2009a,b), and scien-
one established guideline for investigating new clinical applica- tists have perhaps not done enough to correct this misrepresenta-
tions is that of “clinical equipoise,” which is the requirement that tion of their own work in the media.8 While incremental progress 
there be genuine uncertainty in the medical community as to the has clearly been made, large parts of the public still falsely believe 
best form of treatment (Freedman, 1987). It is important that that scientists “have created OBEs in the lab.”
researchers communicate their own sense of this uncertainty in 
a clear manner to volunteer subjects. Similarly, as Chen et  al. Overall, scientists and the media need to be clear and 
(2003) note, physicians who have a lasting relationship with their honest with the public about scientific progress, especially 
patients may be better suited to form a judgment as to whether in the area of using VR for medical treatment.
the patient is motivated by a clear understanding of the nature 
The second concern about applications of VR has to do with 
the well-known tension between autonomy and beneficence in 
6 http://www.apa.org/ethics/code/
7 VR has been used to treat a wide range of mental health issues, including eat-
ing disorders (Ferrer-Garcia et al., 2015), acrophobia (Emmelkamp et al., 2001), 8 For some examples of the full-body illusion being misrepresented in the media, see: 
agoraphobia (Botella et al., 2004), arachnophobia (Carlin et al., 1997), and PTSD http://www.nytimes.com/2007/08/24/science/24body.html http://news.bbc.co.uk/2/
(Rothbaum et al., 2001). See Parsons and Rizzo (2008) for a meta-analysis of these hi/health/6960612.stm http://www.sciencedaily.com/releases/2007/0 8/070823141057.
kinds of treatment. htm
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
applied ethics (Beauchamp and Childress, 2013: Chapter 6). As As the embodiment in avatars and physical robots may be func-
the results surveyed in the first part of this article suggest, VR ena- tionally shallow and may provide only weaker and less stable forms 
bles a powerful form of non-invasive psychological manipulation. of self-control (for example, with regard to spontaneously arising 
One obvious application of VR, then, would be to perform such aggressive fantasies, see Metzinger, 2013c for an example), it is 
manipulations in order to bring about desirable mental states and not clear how such PSM-actions mediated via brain–computer 
behavioral dispositions in subjects. Indeed, early experiments in interfaces should be assessed in terms of accountability and ethical 
VR have done just that, making subjects willing to save more responsibility.9
for their retirement (Hershfield et al., 2011), perform better on Just as VR can be used to increase empathy, it can conceiv-
tests for implicit racial bias (Peck et al., 2013), and behave in a ably be used to decrease empathy. Doing so would have obvious 
more environmentally conscious manner (Ahn et al., 2014). In military applications in training soldiers to have less empathy for 
a paternalistic spirit, such as that of the UK Behavioral Insights enemy combatants, to feel no remorse about doing violence. We 
Team, one might urge that beneficent VR applications such as will not go further into the difficult issues regarding the use of 
these should be put in place among the general populace, perhaps new technology in warfare, but we note this possible alternative 
as a new form of “public service announcement” for the twenty- application of the technology. Apart from increasing or decreas-
first century. Here, we wish to note that doing so may generate ing empathy, the power of VR to induce particular kinds of emo-
another case of conflict between beneficence and autonomy. If tions could be used deliberately to cause suffering. Conceivably, 
individuals do not seek to alter their psychological profile in the the suffering could be so extreme as to be considered torture. 
ways intended by the beneficent VR interventions, then such Because of the transparency of the emotional layers in the human 
interventions may be considered a violation of their autonomy. self-model (Metzinger, 2003), it will be experienced as real, even 
if it is accompanied by cognitive-level insight into the nature of 
Dual Use the overall situation. Powerful emotional responses occur even 
Dual use is a well-known problem in research ethics and the ethics when subjects are aware of the fact that they are in a virtual 
of technology, especially in the life sciences (Miller and Selgelid, environment (Meehan et al., 2002).
2008). Here, we use it to refer to the fact that technology can be 
used for something other than its intended purpose, in particular Torture in a virtual environment is still torture. The fact 
to military applications. In the context of VR technology, one that one’s suffering occurs while one is immersed in a 
will immediately think not only of drone warfare, teleoperated virtual environment does not mitigate the suffering itself.
weapon systems, or “virtual suicide attacks,” but also of interroga-
tion procedures and torture. It is not in the power of the scientists 
and engineers who develop the technology to police its use, but VR Research and the Internet
we can raise awareness about potential misuses of the technology A final concern for the research ethics portion of this article 
as a way of contributing to precautionary steps. has to do with the use of the internet in conjunction with VR 
Here is an example. One possible application of VR would be research. For instance, scientists may wish to observe the pat-
to rehabilitate violent offenders by immersing them in a virtual terns of behavior for users under particular conditions. It is clear 
environment that induces a strong sense of empathy for their that the internet will play a main role in the adoption of VR for 
victims. We see no problem at all with voluntary participation personal use. Users will be able to inhabit virtual environments 
in such a promising use of the technology. But it is foreseeable with other users through their internet connections, and perhaps 
that governments and penal systems adopt mandatory treatment enjoy new forms of avatar-based intersubjectivity. As O’Brolcháin 
using similar techniques, calling to mind Anthony Burgess’ A et al. (2016) suggest, we will soon see a convergence of VR with 
Clockwork Orange. We will not comment on the moral acceptabil- online social networks. The overall ethical risks of this imminent 
ity of such a practice, noting that the details of implementation development have been covered in detail by O’Brolcháin et  al. 
may be an important – and more controllable – unknown factor. (2016); in this section, we will incorporate and expand on their 
Virtual embodiment constitutes historically new form of act- discussion with a focus on questions of research ethics.
ing. Metzinger (2013c) introduced the notion of a “PSM-action” to There is a sizable body of literature covering the main issues 
describe this new element more precisely. PSM-actions are those of internet research ethics (Ess and Association of Internet 
actions in which a human being exclusively uses the conscious Researchers Ethics Working Committee, 2002; Buchanan and 
self-model in her brain to initiate an action, causally bypassing 
the non-neural body (as in Figure 5). Of course, there will have to 
be feedback loops for complex actions, for instance, when seeing 9 It is important to note that teleoperated weapon systems are used in an illegal 
through the camera eyes of a robot, perhaps adjusting a grasping manner today, and it would not be rational to assume that the introduction of military VR-technology in combination with brain–computer interfaces could lead 
movement in real-time (which is still far from possible today). But to a change in this deplorable situation. With German support, the United States 
the relevant causal starting point of the entire action is no longer of America execute citizens of and in other sovereign states (e.g., Yemen, Somalia, 
the body made of flesh and bones, but the conscious self-model Pakistan) without charge, trial, or final judgment (the so-called “extrajudicial kill-
in our brain. We simulate an action in the self-model, in the inner ings”), thereby violating international law (under which lethal force may be used 
image of our body, and a machine performs it. PSM-actions are outside armed conflict zones only as a last resort to prevent imminent threats; see Melzer, 2008 for background and discussion) as well as national law, human 
almost purely “mental,” put they may have far-reaching causal rights, and humanitarian laws. The potential for further illegal or unethical military 
consequences in the real world, for example, in combat situations. applications of VR is high, and one of our major concerns.
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
FiGURe 5 | “PSM-actions”: a test subject lies in a nuclear magnetic resonance tomograph at the weizmann institute in israel. With the aid of data 
goggles he sees an avatar, also lying in a scanner. The goal is to create the illusion that he is embodied in this avatar. The test subject’s motor imagery is classified 
and translated into movement commands, setting the avatar in motion. After a training phase, test subjects were able to control a remote robot in France “directly 
with their minds” via the Internet, while they were able to see the environment in France through the robot’s camera eyes. (Image used with kind permission from 
Doron Friedman and Ori Cohen, cf. Cohen et al., 2014.)
Ess, 2008, 2009). Here, we address the following question: Let us begin with the question of privacy. It is widely accepted 
how should these existing issues of internet research ethics be that researchers have an ethical obligation to treat confidentially 
approached for cases of internet research with the use of VR? The any information that may be used to identify their subjects (see, 
two main issues that we will cover here are privacy and obtaining for example, European Commission, 2013, p. 12). This obliga-
informed consent. We will consider the internet both as a tool and tion is based on the general right to privacy outside of a research 
a venue for research (Buchanan and Zimmer, 2015), while noting context (Universal Declaration of Human Rights, article 12, 1948; 
that virtual environments may place pressure on the distinction European Commission Directive 95/46/EC). Practicing this 
between internet as research tool and internet as research venue. confidentiality may involve, for instance, erasing, or “scrubbing,” 
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personally identifiable information from a data set (O’Rourke, navigation bar. In addition, and more interesting, it is also fore-
2007; Rothstein, 2010). seeable that HMDs will incorporate simultaneous combinations 
As O’Brolcháin et  al. note, immersive virtual environments of augmented, substitutional, and VR, with the user being able to 
will involve the recording of new kinds of personal information, toggle between elements of the three. Such a situation would add 
such as “eye-movements, emotions, and real-time reactions” ambiguity, and perhaps confusion, for attempts to determine the 
(2015, p. 8). We would like to add that immersive VR could even- user’s location in cyberspace. This ambiguity raises the likelihood 
tually incorporate motion capture technology in order to record that users may give consent for data collection in a particular 
the details of users’ bodily movements for the purpose of, for virtual context but then become unaware of the continued data 
example, representing their avatar as moving in a similar fashion. collection as the user changes context. Such a situation might 
Although implementing this scenario may be beyond the capa- occur if users of HMDs are able to toggle between, say, an entirely 
bilities of the forthcoming commercial hardware, it is plausible virtual gaming environment, a look out of the window to the busy 
and rational to assume that the technology may evolve quickly to street below presented through augmented reality, and a family 
include such options. Data regarding the kinematics of users will gathering hundreds of kilometers away using substitutional real-
be useful for researchers from a range of disciplines, especially ity through an omni-directional camera set up at the party. This 
those interested in embodied cognition (Shapiro, 2014). On the worry can be addressed by giving users continuous reminders 
plausible assumption that one’s kinematics is very closely related (after, of course, they have given informed consent) that their 
to one’s personality and the deep functional structure of bodily behavior is being recorded for research purposes. Perhaps the 
self-consciousness – only your body moves in precisely this man- visual display could include a small symbol for the duration of 
ner – there will a highly individual “kinematic fingerprint.” This the time in which data are being collected.
kind of data collection presents a special threat to privacy.
O’Brolcháin et al. (2016) recommend protecting the privacy We leave the implementational details open, but urge the 
for users of online virtual environments through legislation and scientific community to take steps to avoid the abuse of 
through incentives to develop new ways of protecting privacy. As informed consent with this technology, especially in the 
a complement to these recommendations, we wish to highlight interest of preserving public trust.
the threat to privacy created by motion capture technology. 
Unlike eye-movements and emotional reactions, one’s kinemat- A Note on the Limitations of a Code of Ethics for 
ics may be uniquely connected with one’s identity, as indicated Researchers
above. Researchers collecting such data must be aware of its We would like to conclude our discussion of the research ethics 
sensitive nature and the dangers of its misuse. In addition, com- of VR by noting that the proposed (incomplete) code of conduct 
mercial providers of cloud-based VR-technology will frequently is not intended to be sufficient for guaranteeing ethical research 
have an interest of “harvesting,” storing, and analyzing such data in this domain. What we mean here is that following this code 
and users should be informed about such possibilities and give should not be considered to be a substitute for ethical reasoning 
explicit consent to them. on the part of researchers, reasoning that must always remain 
A second main concern in the ethics of internet research is sensitive to contextual and implementational details that cannot 
that of informed consent. In contrast to informed consent for be captured in a general code of conduct. We urge researchers to 
traditional face-to-face experiments, internet researchers may conceive of our recommendations here as an aid in their ongoing 
obtain consent by having subjects click “I agree” after being reflections about the ethical implications and permissibility of 
presented with the relevant documentation. There are a number their own work, and to proactively support us in developing this 
of concerns and challenges regarding the practice of gaining ethics code into more detailed future versions. As we emphasized 
consent for research using the internet as a venue (Buchanan and in the beginning of the article, this work is only intended as a 
Zimmer, 2015, see section Privacy, below), including, of course, first list of possible issues in the research ethics of VR and related 
the fact that actually reading internet privacy policies before technologies. We intend to update and revise this list continu-
accepting them would take far more time than we are willing to ously as new issues arise, although the venue for future revisions 
allocate – on one estimate, it would take each of us 244 h per year is undecided. In any case, we wish to open an invitation for 
(McDonald and Cranor, 2008). constructive input from researchers in this field regarding issues 
We suggest that immersive VR will add further complications that should be added or reformulated.
to these existing issues due to its manipulation of bodily location 
and its dissolution of boundaries between the real and the virtual. Scientists must understand that following a code of ethics 
Consider that entering a new internet venue, say a chatroom or a is not the same as being ethical. A domain-specific ethics 
forum, involves a fairly well-defined threshold at which informed code, however consistent, developed, and fine grained 
consent can be requested before one enters the venue. Due to future versions of it may be, can never function as a 
the centrality of the URL for using the web, one’s own location substitute for ethical reasoning itself.
in cyberspace is fairly easy to track. With VR, by contrast, it is 
foreseeable that one’s movement through various virtual environ-
ments will be controlled by one’s bodily movements, through Risks for individuals and Society
facial gestures, or simply by the trajectory of visual attention in Now consider possible issues that may arise with widespread 
a way unlike internet navigation using a mouse, keyboard, and adoption of VR for personal use. Once the technology available 
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
to the general public for entertainment (and other) purposes, In order to better understand the risks, we recommend 
individuals will have the option of spending extended periods longitudinal studies, further research into the psychologi-
of time immersed in VR  –  in a way this is already happening cal effects of long-term immersion.
with the advent of smartphones, social networks, increasing 
time online, etc. Some of the risks and ethical concerns that we Of course, these studies must be conducted according to the 
have already encountered in the early days of the internet10 will principles of informed consent, non-maleficence, and benefi-
reappear, though with the added psychological impact enabled cence outlined in Section “The Research Ethics of VR.” There 
by embodiment and a strong sense of presence. We all know that are several possible risks that can be associated with long-term 
internet technology has long ago begun to change our self-models immersion: addiction, manipulation of agency, unnoticed psy-
and consequently our very own psychological structure. The com- chological change, mental illness, and lack of what is sometimes 
bination with technologies of virtual and robotic re-embodiment vaguely called “authenticity” (Metzinger and Hildt, 2011, p. 253). 
may greatly accelerate this development. The risks that are discovered through longitudinal studies must 
For instance, consider the infamous case of virtual rape in be directly and clearly communicated to users, preferably com-
LambdaMOO, the text-based multi-user dungeon (MUD). In municated within VR itself.
that virtual world, a player’s character known as “Mr.Bungle” Psychologists have long expressed concern about internet 
used a “voodoo doll” program to control the actions of other use disorder (Young, 1998), and it is a topic of ongoing research 
characters in the house. He forced them to perform a range of (Price, 2011).11 This area of research must now expand in order to 
sexual acts, some of which are especially disturbing (Dibbell, include concerns about addiction to immersive VR, both online 
1993). Users of LambdaMOO were outraged, and at least one and offline. Doing so will require monitoring users who prefer to 
user whose character was a victim of the virtual rape reported spend long periods of time immersed (see Steinicke and Bruder, 
suffering psychological trauma (ibid.). The relevant point to keep 2014 for a first self-experiment). There are two relevant open 
in mind here is that this entire virtual transgression occurred in a questions here. First, how might the diagnostic criteria for addic-
world that was entirely text based. We will soon be fully immersed tion to VR differ from the established criteria for internet use 
in virtual environments, actually embodying – rather than merely disorder and related conditions? Note that the neurophysiological 
describing – our avatars. The results sketched above in Section underpinnings of VR addiction may differ from that of internet 
“Illusions of Embodiment and Their Lasting Effect” suggest that use disorder (Montag and Reuter, 2015) due to the prolonged 
the psychological impact of full immersion will be great, likely illusion of embodiment created by VR technology, and because 
far greater than the impact of text-based role-playing. We must it implies causal interaction with the low-level mechanisms con-
now take steps in order to help users avoid suffering psychological stituting the UI. Second, can we make use of the recommended 
trauma of various kinds. To this end, we will discuss four kinds treatments for internet use disorder for the purpose of helping 
of foreseeable risks: individuals with VR addiction? For instance, Gresle and Lejoyeux 
• long-term immersion; (2011, p. 92) recommend informing users how much time they 
• neglect of embodied interaction and the physical environment; have spent playing an online game, and including non-player 
• risky content; characters in the game to urge players to take breaks. It is plausible 
• privacy. that these strategies would be effective for immersive VR as well, but focused research is needed.
We will offer several concrete recommendations for minimiz- A second concern about long-term immersion has to do with 
ing all four of these kinds of risks to the general public, a number the fact that immersive VR can manipulate the user’s sense of 
of which call for focused research initiatives. agency (Gallagher, 2005). In order to generate a strong illusion 
of ownership for the virtual body, the VR technology must track 
The Effects of Long-Term Immersion the self-generated movements of the user’s real body and render 
First, and perhaps most obviously, we simply do not know the the virtual body as moving in a similar manner.12 When things are 
psychological impact of long-term immersion. So far, scientific working well, users experience an illusion of ownership of the vir-
research using VR has involved only brief periods of immersion, tual body (the avatar is my body), as well as an illusion of agency 
typically on the order of minutes rather than hours. Once the (I am in control of the avatar). Importantly, the sense of agency in 
technology is adopted for personal use, there will be no limits VR is always indirect; control of the avatar is always mediated by 
on the time users choose to spend immersed. Similarly, most the technology. To be more precise, the virtual body representation 
research using VR has been conducted using adult subjects. Once has been causally coupled with and temporarily embedded into 
VR is available for commercial use, young adults and children the currently active conscious self-model in the user’s brain – it 
will be able to immerse themselves in virtual environments. The is not that some mysterious “self ” leaves the physical body and 
risks that we discuss below are especially troublesome for these “enters” the avatar, but rather a novel functional configuration in 
younger users who are not yet psychologically and neurophysi-
ologically fully developed.
11 Internet use disorder is listed as an area requiring further research in the DSM-5, 
but it is not (yet) an official disorder according to the manual.
12 If the real body is not in motion, then co-location of the virtual body with the real 
10 See Gregory Lastowka, 2010 for a thoughtful treatment of some of the relevant body as seen from the first-person perspective can be sufficient for the illusion of 
issues. ownership (Maselli and Slater, 2013).
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
which two body representations dynamically interact with each do not know whether long-term immersion poses a threat for 
other. However, the causal loop in principle enables bidirectional mental health. Future research ought to investigate whether fac-
forms of control, or even unnoticed involuntary influence. The tors such as the duration of immersion, the content of the virtual 
fact that the user’s sense of agency in VR is always continuously environment (including the user’s own avatar or the way in which 
maintained by the technology is an important one for at least two the software controls the automatic behavior, facial gestures, or 
reasons. First, the technology could be used to manipulate users’ gaze of other avatars), and the user’s pre-existing psychological 
sense of agency. Second, as we discuss in the general context of profile might have lasting negative effects on the mental health 
mental health below, long-term immersion could cause low-level, of users. As mentioned above (see Ethical Experimentation), we 
initially unnoticeable psychological disturbances involving a loss suspect that heavy use of VR might trigger symptoms associated 
of the sense of agency for one’s physical body. with Depersonalization/Derealization Disorder (DSM-5 300.14). 
VR technology could manipulate users’ sense of agency by Overall, the disorder can be characterized as having chronic feel-
creating a false sense of agency for movements of the avatar that ings or sensations of unreality. In the case of depersonalization, 
do not correspond to the actual body movements of the user. The individuals experience an unreality of the bodily self, and in the 
same could be true for “social hallucinations,” i.e., the creation case of derealization, individuals experience the external world 
of the robust subjective impression of ongoing social agency, of as unreal. For instance, those suffering from the disorder report 
engaging in a real, embodied form of social interaction, which, feeling as if they are automata (loss of the sense of agency), and 
however, in reality is only interaction with an unconscious feeling as if they are living in a dream (see Simeon and Abugel, 
AI or with complex software controlling the simulated social 2009 for illustrative reports from individuals suffering from 
behavior of an avatar. Using only a computer screen, a modified depersonalization).13 Note that Depersonalization/Derealization 
mouse, and headphones, a false sense of agency was created Disorder involves feelings of unreality but not delusions of unre-
in Daniel Wegner’s well-known “I Spy” experiments (Wegner ality, there is a dissociation of the low-level phenomenology of 
and Wheatley, 1999; Wegner, 2002). In those experiments, “realness” from high-level cognition. That is, someone suffering 
subjects reported that they felt themselves to be in control of from depersonalization may lose the sense of agency, but will not 
a cursor selecting an icon on a computer screen when in fact thereby form the false belief that they are no longer in control of 
the cursor was being controlled by someone else. The illusion their own actions.
of control was induced by auditory priming –  subjects heard Depersonalization/Derealization Disorder is relevant for 
a word through headphones that had a semantic association us here because VR technology manipulates the psychological 
with the icon that was subsequently selected by the cursor. It is mechanisms involved in generating experiences of “realness,” 
reasonable to think that Wegner’s method can be implemented mechanisms similar or identical to those that go awry for those 
rather easily in VR. While immersed in VR, subjects can receive suffering from the disorder. Even though users of VR do not believe 
continuous audio and visual cues intended to influence their that the virtual environment is real, or that their avatar’s body is 
psychological states. Future experimental work can determine really their own, the technology is effective because it generates 
the conditions under which subjects will experience a sense illusory feelings as if the virtual world is real (recall the virtual pit 
of agency for movements of the avatar that deviate from the from Section “Illusions of Embodiment and Their Lasting Effect” 
subject’s actual body movements (as during an OBE or in the above). What counts is the variable degree of transparency or 
dream state, see Kannape et al., 2010 for an empirical study). opacity of the user’s own conscious representations (Metzinger, 
Important parameters here will likely be the timing of the false 2003). Our concern is that long-term immersion could cause 
movement, the degree to which the false movement deviates damage to the neural mechanisms that create the feeling of reality, 
from the actual position of the body, and the context of the of being in immediate contact with the world and one’s own body. 
movement within the virtual environment (including, for Heavy users of VR may begin to experience the real world and 
instance, the attentional state of the subject). their real bodies as unreal, effectively shifting their sense of reality 
Creating a false sense of agency in VR is a clear violation of exclusively to the virtual environment.14 We recommend focused 
the user’s autonomy, a violation that becomes especially worri- longitudinal studies on the impact on mental health of long-term 
some as users spend longer and longer periods of time immersed. immersion in VR. These studies should especially investigate 
Here, we will not insist that all cases of violating autonomy in risks for dissociative disorders, such as Depersonalization/
this manner are ethically impermissible, noting that some such Derealization Disorder.
violations may be subtle and beneficent, a kind of virtual “nudge” 
in the right direction (Thaler and Sunstein, 2009). In addition, 
human beings often willfully choose to decrease their autonomy, 
13 
as in drinking alcohol or playing games. But we do claim that There is a sizeable literature on depersonalization/derealization. Some of the central works include Steinberg and Schnall, 2001; Radovic and Radovic, 2002; 
creating a false sense of agency in VR is an unacceptable violation Simeon and Abugel, 2009; Sierra, 2012.
of individual autonomy when it is non-beneficent, such as when 14 We should be clear here that we are only speculating about a possible causal 
it is done out of avarice, for example. Manipulating the sense of connection between long-term immersion and experiences of depersonalization/
agency for users in VR is a topic that deserves attention from derealization. The etiology of the disorder is still not well understood. It is well-
regulatory agencies. known that episodes of depersonalization/derealization can be triggered by stress, panic attacks, and the use of some drugs (Simeon, 2004). One prominent theory 
A third concern that we wish to raise about long-term immer- suggests that chronic depersonalization/derealization may be caused by childhood 
sion is that of risks for mental health. As stated above, we simply trauma (ibid.), though see Marshall et al. (2000).
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
A final concern for long-term immersion stems from the fact immersive VR would be unedifying, making people more shallow 
that some may consider experiences in the virtual environment to as they retreat from society in favor of an artificial social world 
be “inauthentic,” because those experiences are artificially gener- in which their decisions are made for them. Brolcháin et al. raise 
ated. This concern may remind some readers of Robert Nozick’s this sort of concern:
well-known thought experiment about an “Experience Machine” 
that can provide users with any experience they desire (Nozick, With little exposure to “higher” culture, to great works 
1974, p. 42–45). Nozick uses the thought experiment to raise a of art and literature; and without the skills (and maybe 
problem for utilitarianism, urging his readers to consider reasons the attention spans) to enjoy them; people would be less 
why one might not wish to “plug-in” to the machine, claiming able to engage with the world at a deep level. People 
that “something matters to us in addition to experience” (Nozick, without exposure to great works and ideas might find 
1974, p. 44). The interesting question, of course, now becomes that [their] inner lives are shaped to a large degree 
what would happen if this “additional something” can be added by market-led cultural products rather than works of 
to the experience itself, for example by advanced VR-technology depth and profundity. (2015, p. 20)
creating the phenomenal quality of “authenticity,” of direct refer-
ence to something “meaningful,” for example by a more robust We agree that such a scenario would be undesirable, but wish 
version of naïve realism on the level of subjective experience to counterbalance this concern by reminding readers that it is 
itself or by manipulation of the user’s emotional self-model. not unique to VR. It is a concern that can be applied in various 
While Nozick suggests that many of us would not wish to plug- degrees to other media technology as well, going all the way back 
in to the experience machine for the reason just stated, recent to worries about the written word in Plato (Phaedrus 274d–275e). 
work by Felipe de Brigard suggests otherwise. De Brigard (2010) The printing press, for example, can enable one to disseminate 
presented students with several variations on the thought experi- great works of literature, but it can also enable the dissemination 
ment all with an important twist on Nozick’s original version. In of vulgarity – and it certainly changed our minds. Readers with 
de Brigard’s version, we are told that we are already plugged-in vulgar tastes can “immerse” themselves as they wish. The same 
to an experience machine and we are asked if we would like to goes for photography and motion pictures. The important point 
unplug in order to return to our “real” lives. Many of de Brigard’s is as follows. There is no reason to doubt that works of great depth 
students replied that they would not wish to unplug, leading de and profundity can be produced by artists who choose VR as their 
Brigard to suggest that our reactions to the thought experiment medium. Just as film emerged as a new predominant art form in 
are influenced more by the status quo bias (Samuelson and the twentieth century, so might VR in the twenty-first century. We 
Zeckhauser, 1988) than by our valuing of something more than predict that immersive VR-technology will gradually lead to the 
experience. It is the status quo bias, de Brigard suggests, that gives emergence of completely new forms of art (or even architecture, 
us pause about plugging-in to the machine (in Nozick’s version of see Pasqualini et al., 2013), which may be hard to conceive today, 
the thought experiment) just as it is the status quo bias that gives but which will certainly have cultural consequences, perhaps 
us pause about unplugging (in de Brigard’s version). even in our understanding what an artistic subject and esthetic 
Overall, de Brigard’s results offer initial reasons to be skeptical subjectivity really are.
about Nozick’s supposition that we would not plug-in because we 
value factors beyond experience alone. Even with this skepticism, 
though, many of us may still feel that there is something false, Neglect of Others and the Physical Environment
“inauthentic,” or undesirable about living large portions of one’s As users spend increasing time in virtual environments, there 
life in an entirely artificial environment, such as VR. Apart from is also a risk of their neglecting their own bodies and physical 
the dubious essentialist metaphysics lurking behind the vague environments – just as for many people today posing and engag-
and sometimes ideologically charged notion of an “authentic self,” ing in disembodied social interactions via their Facebook account 
it is important to note how such intuitions are historically plastic has become more important than what was called “real life” in the 
and culturally embedded: they may well change over time as past. In extreme cases, individuals refuse to leave their homes for 
larger parts of the population begin to use advanced forms of VR extended periods of time, behavior categorized as “Hikikomori” 
technology. As an example, please note how already today we find by the Japanese Ministry of Health. VR will enable us to interact 
a considerable number of people who are not able to grasp the with each other in new ways, not through disembodied interac-
difference between “friendship” and “friendship on Facebook” tion, as in the texts, images, and videos of current social media, 
any more. Fully engaging with the issue of losing “authenticity” but rather through what we have called the illusion of embodi-
in virtual environments would likely require entering into some ment. We will interact with other avatars while embodied in our 
deep philosophical waters, and we are unable to do so here, though own avatars. Or perhaps we will use augmented reality through 
we will touch on some of the relevant issues below. Apart from the omni-directional cameras that allow us to enjoy the illusion of 
deeper philosophical issues, there is one important point that we being in the presence of someone who is far away in space and/
wish to make before moving on. or time. To put it more provocatively, we may soon, as Norbert 
The point has to do with the way in which we imagine the Wiener anticipated many years ago, have the ability to “telegraph” 
possibilities of VR for personal use. One reason behind an asser- human beings (Wiener, 1954, p. 103–104). Telepresence is likely 
tion that long-term immersion would be an inauthentic way of to become a much more accessible, immediate, comprehensive, 
spending one’s time is that one might assume that the content of and embodied experience.
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
Our general recommendation on this theme is for focused the children disrupt their playing indicate that this concern is 
research into the following question: What, if anything, valid and serious.16
is lost in cases of social interactions that are mediated Clark (2003) takes a notably different approach to these kinds 
using advanced telepresence in VR? If such losses were of issues, raising the point that, instead of treating VR and related 
unnoticed, what negative effects for the human self-model technologies as a replacement for in-the-flesh interaction, we 
could be expected? should think of them as providing opportunities for new and 
perhaps enhanced modes of human interaction. Rather than 
This question has been a major theme in some of Hubert unsatisfactory reproductions of familiar modes of interaction, the 
Dreyfus’ work on the philosophy of technology. Dreyfus has technology should be developed with an eye toward “expanding 
emphasized that mediating technologies may not capture and reinventing our sense of body and action” (2003, p. 111). 
something of what is important for real-time interactions in the Consider, for example, using a combination of substitutional and 
flesh, what, following Merleau-Ponty, he calls “intercorporeal- augmented reality to see a representation of some of the physi-
ity” (Dreyfus, 2001, p. 57). When we are not present in the ological states of your partner who is many miles away – such 
flesh with others, the context and mood of a situation may be as a soft flash over the body in synchrony with the heartbeat (as 
difficult to appreciate – if only because the bandwidth and the in Aspell et  al., 2013). That and similar uses of the technology 
resolution of our internal models are much lower. Perhaps more could plausibly enhance embodied (though mediated) social 
importantly, there is a concern that mediating technologies will interaction. As with many other topics addressed here, future 
not allow us to pick up on all of the subtle bodily cues that research will be crucial for our understanding of which uses of the 
appear to play a major role in social communication through technology will be best for enabling positive forms of (mediated) 
unconscious entrainment (Frith and Frith, 2007), cues that social interaction.
involve ongoing embodied interaction (Gallagher, 2008; de Clark’s recommendation that we use the technology as an 
Jaegher et al., 2010). enhancer rather than a replacement does have some appeal. 
In addition to the concerns about losing embodied signaling However, what counts as an “enhancement,” and what as therapy 
for communication, we might also consider what is lost from or mere life-style decision, has been a topic of ethical debates for 
the sense modalities that are not (yet) integrated into VR. As a long time, for instance, in assessing the correct use of phar-
Sherry Turkle puts it, when these kinds of technology “keep maceutical cognitive enhancement (Metzinger and Hildt, 2011; 
grandparents from making several-thousand-mile treks to see Metzinger, 2012). We should also note that his recommendation 
their grandchildren in person (and there is already evidence may not entirely address the concerns raised by Dreyfus, Turkle, 
that they do), children will be denied something precious: the and others. The foreseeable problem is that the general public sim-
starchy feel of a grandmother’s apron, the smell of her perfume ply will not share Clark’s vision, choosing to use the technology 
up close, and the taste of her cooking” (Harmon, 2008; Turkle, as a de facto replacement for traditional modes of interaction (as 
2011, p. 342). Advances in technology could conceivably address Turkle notes in the passage above). Are “Facebook-friendships” 
Turkle’s point about other perceptual modalities, but there social enhancements or social disabilities? In such a situation, we 
remains a question about what may be lost even if we can create must remain mindful of what may be lost, especially when the 
virtual content for other sense modalities.15 One recent finding technology may encourage less frequent “in-the-flesh” visits to 
that should raise concern here is that depression is more likely in the infirm and immobile.
older adults who have less social contact in person regardless of We wish to close this discussion of the ways in which VR might 
their amount of telephone, written, and email contact (Teo et al., attenuate our contact with others and with our physical environ-
2015). Apart from this troubling finding, even if the technology ments by revisiting a point briefly made in the previous section 
eventually enables rich social interaction through telepresence, on a loss of authenticity during long-term immersion. As noted 
the concern remains that heavy use of such technology will lead above in the discussion of Nozick’s experience machine, many 
to neglect or even animosity toward one’s actual physical and readers might have the intuition that spending long periods of 
social environment. The recurring tragedies of parents with time in virtual environments is “somehow inauthentic.” Yet, what 
“gamer rage” who have injured and killed their children because counts for the applied ethics of VR are not intuitions, but rather 
rational arguments and empirical evidence. We would like to note 
that a likely relevant factor here may be whether those long peri-
15 All of these concerns bring up the question of whether the problem is merely a ods of immersion involve forms of intersubjective engagement 
shortcoming in the technology, or something more fundamental. That is, should with others that are subjectively experienced as meaningful, and 
we only be concerned about losing important information through mediated inter- how this experience is integrated into our culture. Along these 
actions, information such as bodily cues and tactile sensations? If so, then advances 
in technology can conceivably address that concern. Or is there something else lines, one may suggest that the artificial nature of the virtual 
that is lost when not present in the flesh with others? It seems that thinkers such environment is not as important compared to whether or not the 
as Dreyfus wish to suggest that there is something else that is lost when we lose environment affords intersubjective engagement experienced as 
“intercorporeality,” something that cannot be captured with better and better tech- meaningful (see Bostrom, 2003, p. 245–55 and Chalmers, 2005 
nology. Still, it remains somewhat difficult to articulate what that “something else” 
might be. One possibility is that social interactions that are mediated by advanced 
technology lose some form of “authenticity” as discussed above. It is also worth 
noting that our epistemic limitations may be relevant: in the case of VR, we do not 16 For a list of examples, see: http://movingtolearn.ca/2013/gamer-rage-child-
yet know the way in which social interaction will be altered. abuse-a-growing-problem-deserving-our-attention (retrieved 1 December 2015).
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
for similar ideas). This, of course, opens the possibility that available for use after their human model is dead. Thus, we will be 
ultimately shallow or even largely meaningless social interac- able to “resurrect” the dead in VR. The ability to body-swap and 
tions (once again, think of today’s Facebook-“friendships” and to interact with the dead in this way may offer great opportunity 
“likes”) are experienced as substantial by users who are really only for therapy in the hands of the beneficent, but it could easily lead 
overwhelmed by the possibilities of future VR-technology, and to profound trauma, especially in the hands of characters such as 
which are subsequently described as meaningful. A shallow form Mr. Bungle, mentioned above.
of social interaction could then become culturally assimilated These considerations raise difficult questions about which 
and thereby “normalized” (Metzinger and Hildt, 2011, p. 247). regulatory actions would facilitate the best overall outcome. On 
Normalization is a complex sociocultural process by which certain the one hand, there are good reasons for taking a fairly restric-
new norms become accepted in societal practice, a process that is tive approach to avatar ownership. On the other hand, there are 
often mediated by the availability of new technologies, a process also reasons for allowing individuals maximum freedom in their 
that changes our very own minds and which, therefore, carries creation and use of avatars. Of course, one’s approach to such 
the risk of unnoticed self-deception. Here, we cannot explore this questions will likely reflect whether one’s political philosophy has 
rich (and controversial) philosophical territory, but note that it more paternalistic or libertarian leanings. We will consider the 
may be relevant for grappling with the worry of “inauthenticity” reasons for each approach in turn.
in virtual environments. A reasonable starting point on this issue would be to treat 
avatars in an analogous manner to personality rights relating 
Risky Content to the publication of photos. They are public representations of 
Another main concern for users of VR is that of virtual content. persons. Interestingly, societies and legal systems exhibit con-
One might begin with the general rule of thumb that red lines siderable differences in their underlying moral intuitions here. 
not to be crossed in reality should be the default red lines in VR. One important conceptual issue here may be determining the 
One obvious problem, though, is that users will almost certainly relevant degree of similarity between an avatar and a human per-
seek out VR as a way of crossing red lines with impunity. A son. Just as many accept the right of an individual to control the 
second possible problem is that this rule of thumb would make commercial use of his or her name, image, likeness, one might, 
VR even more subjectively real. One main issue here is whether for example, interpret the “right to my own avatar” a property 
some particular kinds of content in VR should be discouraged right as opposed to a personal right. Therefore, the validity of 
in various ways. Obvious candidates for such content would be the right of publicity could be taken to survive the death of the 
sex (virtual pedophilia, virtual rape) and violence. But there are biological individual. There will be new questions about the 
perhaps less obvious kinds of content that should be consid- ownership (and individuation) of avatars. The likeness between 
ered, such as content encouraging and reinforcing undesirable a person and their avatar may or may not be an important factor. 
personality traits, including those identified as the “dark triad” Instead of likeness, we might individuate avatars by a unique 
(Paulus and Williams, 2002). The dark triad refers to narcissism, proper name that can be represented in the virtual space, as in 
Machiavellianism, and psychopathy. Individuals may find it many video games. How does one assign an unequivocal iden-
appealing to spend time in virtual worlds designed to reward tity to the virtual representation of a body or a person? Could 
characters that exhibit traits associated with the dark triad. For there be something like a chassis plate number, a license plate, 
example, the MMORPG EVE Online is known for fostering a or a “virtual vehicle identification number? (VVIN)? We already 
style of play that involves manipulating and deceiving other have digital object identifiers (DOIs) for electronic documents 
players. The VR version of EVE Online, EVE: Valkyrie, has been and other forms of content, a form of persistent identification, 
described as “[u]ndoubtedly the most heavily anticipated virtual with the goal of permanently and unambiguously identifying 
reality game.”17 Based on some of the empirical results surveyed the object with which a given DOI is associated. But what about 
above (see “Illusions of Embodiment and Their Lasting Effect”), an avatar that is currently used by a human operator, namely 
there is cause for concern about behavioral patterns rewarded in by functionally and phenomenologically identifying with it? 
immersive games such as EVE: Valkyrie having a lasting influence Should we dynamically associate a “digital subject identifier” 
on the psychological profile of users. (DSI) with it? There will also be questions about whether some 
Apart from the behaviors encouraged by particular virtual kinds of virtual activities should be censored. Examples of 
environments, there are concerns about the content that can be such activities having to do with sex and violence are left to the 
created when users will have the freedom to create and design reader’s imagination. Another kind of content worth consider-
their own avatars. For instance, one goal of our own project VERE ing may be the use of virtual environments for indoctrination 
is to create software that enables untrained users to generate an into extremist groups.
avatar that resembles any human being with fairly little time With these initial thoughts in place, now consider the reasons 
and effort. This application would in principle allow for “body for taking a fairly strict regulatory stance on the ownership of 
swapping,” in which users enter the bodies of others (Petkova and one’s own avatar. After mentioning the pressure from social 
Ehrsson, 2008). It is also worth noting that these avatars will be networks such as Facebook for users to use their real identities, 
O’Brolcháin et al. recommend the development of technologies 
similar to digital watermarking that would ensure “that only the 
17 http://www.craveonline.com/culture/878953-top-10-virtual-reality-games-will- genuine owner of an avatar can use it” (2015, p. 22). Would this 
convince-strap-vr-headset#/slide/10 (retrieved 30 September 2015). perhaps have to be a “DSI,” as we proposed above? They suggest 
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
that such technology would help protect the autonomy and Privacy
privacy of users. Along the same lines, if one were to identify Privacy is, of course, a major concern with contemporary infor-
strongly with one’s own avatar, the “theft” and use of that avatar mation technology (van den Hoven et al., 2014), and there are 
by another may be extremely disturbing. Importantly, avatar theft further concerns about privacy with the foreseeable convergence 
may also create completely new opportunities for impersonation between VR and social networks (O’Brolcháin et al., 2016). Here, 
and fraud, for example also using physical robots. we wish to offer only a few quick remarks on this topic, noting that 
From a more theoretical point of view, we might distinguish this issue deserves further attention. Commercial applications 
between internal and external self-models: the internal self-model of virtual environments introduce new possibilities for targeted 
is in the brain of the user, and it is grounded in his or her body advertising or “neuromarketing,” thus attacking the individual’s 
(Metzinger, 2014), whereas external person- and body-models mental autonomy (Metzinger, 2015). By tracking the details of 
can be created in virtual environments. Here, the specific, histori- one’s movements in VR, including eye movements, involuntary 
cally new kind of action that needs to be ethically assessed and facial gestures, and other indicators of what researchers call low-
legally regulated takes place when a user identifies with a potential level intentions or “motor intentions” (Riva et al., 2011), private 
external model of the self by dynamically integrating it with the agencies will be able to acquire details about one’s interests and 
internal model of the self already active in his or her brain. The preferences in completely new ways (Coyle and Thorson, 2001). 
core question seems to be what consequences we draw from If avatars themselves should in the future be used as “humanoid 
the potential for phenomenological ownership to legal notions of interfaces,” consumers can be influenced and manipulated by 
ownership. Virtual identification can cause real suffering, and real real-time feedback of the avatar’s own facial and eye move-
suffering is relevant for the law. ments (for example, via automatic and unconscious responses 
Without denying the value of protecting avatar ownership, we in their mirror-neuron system; Rizzolatti and Craighero, 2004). 
would now like to consider two reasons for taking a less restric- Commercials in VR could even feature images of the target audi-
tive, more libertarian, approach. First, implementing control ence himself or herself using the product. The use of big data 
over the use of particular avatars may be impractical. So far, to “nudge” users (“Big Nudging”) combined with VR could have 
attempts to curb digital piracy using technology have not been long-lasting effects, perhaps producing changes in users’ mental 
very successful, and there is no reason to think that things will mechanisms themselves.
be different for avatars. In fact, regulation and control may be 
even more difficult with avatars due to questions raised above Users ought to be made aware that there is evidence that 
having to do with avatar individuation and degrees of similarity. advertising tactics using embodiment technology such 
Say a user creates an avatar that is similar but not pixel-for-pixel as VR can have a powerful unconscious influence on 
identical to another user’s avatar.18 Where precisely should we behavior.
draw the line between theft and acceptable similarity? Protecting 
avatar ownership might lead to a regulatory quagmire. Even if the 
appearance of the avatar is not highly relevant for ownership, we SUMMARY
would need to establish a widely accepted alternative method of 
individuation, such as a unique proper name that cannot be easily In this article, we have considered some of the risks that may arise 
forged. The second reason for taking a less restrictive approach with the commercial and research use of VR. We have offered 
would be out of concern for individual creative freedom. As noted some concrete recommendations and noted areas in which 
above, VR holds the promise of being a powerful new artistic further ethical deliberation will be required. One main theme of 
medium – the creative possibilities are astonishing. The fact that the article is that there are several open empirical questions that 
regulations on avatar ownership may restrict those possibilities should be urgently addressed in a beneficent research environ-
must be taken into consideration. ment in order to mitigate risks and raise awareness for users of VR 
in the general public. More research is needed. Here, one of our 
Avatar ownership and individuation will be an important main goals was to provide a first set of ethical recommendations 
issue for regulatory agencies to consider. There are strong as a platform for future discussions, a set of normative starting 
reasons to place restrictions on the way in which avatars points that can be continuously refined and expanded as we go 
can be used, such as protecting the interests and privacy of along (see Table 1).
individuals who strongly identify with their own particu- Let us end by making one more general point, an observation 
lar avatar on social networks. On the other hand, these which is of a more philosophical nature. VR is the representation 
restrictions may prove impractical to implement and may of possible worlds and possible selves, with the aim of making 
unnecessarily limit personal creative freedom. them appear as real as possible – ideally, by creating a subjective 
sense of “presence” in the user. Interestingly, some of our best 
theories of the human mind and conscious experience itself 
describe it in a very similar way: leading current theories of brain 
18 The importance of personal identity for moral philosophy is well-known (Parfit, 
1984; Shoemaker, 2014). The considerations here introduce the additional compli- dynamics (Friston, 2010; Hohwy, 2013; Clark, 2015) describe it as 
cation of identity for virtual representations of persons. See Vallor (2010, especially the constant creation of internal models of the world, predictively 
pp. 166–167) and Rodogno (2012) for insightful discussions. generating hypotheses – virtual neural representations – about 
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
TABLe 1 | veRe code of conduct for the ethical use of vR in research and by the general public.
ReCOMMeNDATiONS FOR THe ReSeARCH eTHiCS OF vR
1.  Non-maleficence
 a. No experiment should be conducted using virtual reality with the foreseeable consequence that it will cause involuntary suffering or serious or lasting harm to a 
subject.
 b. A rational, evidence-based identification and minimization of risks (also those pertaining to a more distant future) ought to be a part of research itself.
2.  informed consent
 a. Informed consent for VR experiments ought to include an explicit statement to the effect that immersive VR can have lasting behavioral influences on subjects, and 
that some of these risks may be presently unknown.
 b. Experimental VR research should not be carried out on subjects incapable of informed consent.
3.  Transparency and media ethics
 a. In experimental work developing new clinical applications, researchers should be careful not to create false hopes in patients by repeatedly reminding them of the 
merely experimental nature of the research.
 b. VR researchers aiming at new clinical applications should work in close collaboration with physicians who may be better situated to make informed judgments about 
the suitability of particular patients for new trials.
 c. Scientists and the media need to be clear and honest with the public about scientific progress, and not only in the area of using VR for medical treatment.
 d. In interacting with the media, scientists should cultivate a proactive attitude, especially if they are the first to become aware of novel types of risks through their own 
work. Communication with the public, if needed, should be self-initiated, an act of taking control and acting in advance of a future situation, rather than just reacting.
4.  Dual use
 a. Potential military applications of VR, AR, and SR should be closely monitored by policy makers and funding agencies alike.
 b. Torture in a virtual environment is still torture. The fact that one’s suffering occurs while one is immersed in a virtual environment does not mitigate the suffering itself.
 c. Policy makers should aim at international arrangements among countries to add VR, AR, and SR in a process to harmonize lists of dual-use technologies to be 
controlled.
5.  internet research
 a. The scientific community has to take steps to avoid the abuse of informed consent with this technology, especially in the interest of preserving public trust.
 b. The ability to toggle between VR, AR, and SR may create situations in which users are not able to maintain an understanding of when their informed consent to 
share information is in effect. Users should be repeatedly reminded within VR that they have given informed consent.
6.  The Limitations of a Code of Conduct
 a. Scientists must understand that following a code of ethics is not the same as being ethical. A domain-specific ethics code, however consistent, developed, and 
fine-grained future versions of it may be, can never function as a substitute for ethical reasoning itself.
 b. Such reasoning must be conducted in a way that is sensitive to the contextual and implementational details of particular experimental paradigms, details that cannot 
be captured by a general code of conduct.
ReCOMMeNDATiONS FOR THe USe OF vR BY THe GeNeRAL PUBLiC
1.  Long-term immersion 
 a. Longitudinal studies and further research into the psychological effects of long-term immersion are needed.
 b. Users must be made aware that these studies are seriously limited in that they will, due to ethical constraints, exclude users who may be most vulnerable (such as 
children or those with latent mental illness). Some of these vulnerabilities may be unknown to science and unknown to the users themselves.
2.  increasing virtualization of social interactions – we call for focused research, large longitudinal studies, into the following questions:
 a. What, if anything, is lost in cases of social interactions that are mediated using advanced telepresence in VR?
 b. If such losses were unnoticed, what negative effects for the human self-model could be expected?
3.  Risky content
 a. As compared to the viewing of traditional movies containing graphic violence or pornography, the impact of full immersion settings and the associated risk of users 
suffering psychological trauma will steadily increase as VR technology advances. Users have to be made aware of this possibility.
 b. VR technology holds the potential to create robust social hallucinations, to directly manipulate the sense of agency, to modulate personality traits via identification 
with virtual characters, or to causally interact with deeper levels of self-consciousness (UI-manipulation). Users have to be made aware of this possibility.
 c. Avatar ownership will be an important issue for regulatory agencies to consider. There are strong reasons to place restrictions on the way in which avatars can be 
used, such as protecting the interests and privacy of individuals who strongly identify with their own particular avatar on social networks. On the other hand, these 
restrictions may prove impractical to implement and may unnecessarily limit personal creative freedom. Regulators must strike a rational balance between these 
concerns.
4.  Privacy
 a. Users ought to be made aware that there is evidence that advertising tactics using embodiment technology, such as VR, can have a powerful unconscious influence 
on behavior. For example, a combination of “Big Nudging” strategies (collecting big data for the purposes of nudging the general public) with VR technology could 
have long-lasting effects, which might also affect underlying mental mechanisms themselves.
 b. Data protection: users ought to be made aware of new risks involving surveillance, such as reading out “motor intentions” or a “kinematic fingerprint” during avatar 
use.
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Madary and Metzinger Real Virtuality: A Code of Ethical Conduct
the hidden causes of sensory input through probabilistic infer- are just beginning to understand. It is this complex convolution 
ence. Slightly earlier, some philosophers (Revonsuo, 1995, p. 55; that makes it so important to think about the Ethics of VR in a 
Revonsuo, 2009, p. 115.; Metzinger, 2003, p. 556; 2008, 2009a, p. critical, evidence-based, and rational manner.
6, 23, pp. 104–108; Westerhoff, 2015 for overview and discussion) 
have pointed out at length how conscious experience exactly is a AUTHOR CONTRiBUTiONS
virtual model of the world, a dynamic internal simulation, which 
in standard situations cannot be experienced as a virtual model MM drafted the initial outline of the article and then both MM 
because it is phenomenally transparent – we “look through it” as and TM contributed written content.
if we were in direct and immediate contact with reality. What is 
historically new, and what creates not only novel psychological ACKNOwLeDGMeNTS
risks but also entirely new ethical and legal dimensions, is that 
one VR gets ever more deeply embedded into another VR: the The authors wish to thank Mel Slater, Patrick Haggard, Angelika 
conscious mind of human beings, which has evolved under very Peer, and all members of the VERE project for critical discussion 
specific conditions and over millions of years, now gets causally and detailed proposals. We are also grateful to the three reviewers 
coupled and informationally woven into technical systems for of this contribution for recommending substantial improvements 
representing possible realities. Increasingly, it is not only cultur- to the original draft.
ally and socially embedded but also shaped by a technological 
niche that over time itself quickly acquires a rapid, autonomous FUNDiNG
dynamics and ever new properties. This creates a complex convo-
lution, a nested form of information flow in which the biological This work was funded by FP7 257695 Virtual Embodiment and 
mind and its technological niche influence each other in ways we Robotic Re-Embodiment (VERE).
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