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Q. What questions drew you, in the years before you began your research (both as an undergraduate
student, and as a graduate student), to become interested in the relationship between the brain and 'self'; and to what
extent did you think such questions could be approached experimentally prior to beginning your own research?
A. The fact that the brain - this small but enormously complex mass - is capable to produce something like a human being -
like my self - with the capability to experience, to reason, to feel, to remember and to be conscious fascinated me long
before my studies. Then, during my studies I realized that all we investigate in cognitive and clinical neuroscience is
somehow also about the self: no matter if we study human basic visual perception or social interaction everything
relates at the same time to the self. This is one of the reasons why I got more interested in these very old
questions that have interested philosophers for a long time: what is actually the self? Why do we normally only perceive
one self in space and time? Is the self necessarily bound to our body or how much body do we need to have a self? How
does this "feeling of a self" evolve in the brain? While working in neurological and psychiatric institutions and
seeing patients where exactly this sense of self is disturbed this interest got even strengthened.
During my studies I read mainly about clinical cases with disturbed sense of self and was not so much aware of
experimental research on these questions (also due to the fact that there is less experimental literature about the
self). Only during my final thesis at university I got interested in the experimental approach and thought about
how virtual reality can or does alter self awareness.
Q. Describe your thought process that led, ultimately, to the development of the procedure for the experiment whose
results are reported in the article "Video Ergo Sum: Manipulating Bodily Self-Consciousness".
A. We tried to study bodily self consciousness in healthy subjects by manipulating their sense of self. Contrary to
e.g. visual research it is very hard to investigate the self since it is usually always present in healthy subjects- you
cannot just compare conditions with or without the self. My professor Olaf Blanke did already scientific research on
patients with out-of-body experiences, a condition where the self is temporarily separated from the body. But research
with patients is rather complicated since such cases are rare and patients are often in a difficult situation and
show additional symptoms etc. Studying healthy subjects allow more systematic investigations. We therefore looked in
the literature for a suitable paradigm that we could use and found it in experimental psychology; the so called rubber
hand illusion, where synchronous stroking of the unseen own hand and a seen rubber hand lead to attribution of the
rubber hand to the own self. We decided to use a simple VR set-up in order to do a similar manipulation on the whole
body.
Q. Describe, in as much detail as you deem necessary, the
experiment itself.
A. Through a simple VR set-up we filmed the subject from behind and projected it on a HMD. With this set-up the subjects saw
themselves in true 3D in front of them at a distance of 2m. Then we stroked them either synchronously or not with the
seen body on their back. In the synchronous conditions subjects felt as if the virtual body was their body and
self-localized themselves closer towards the virtual body than they actually were. This was not the case for the
asynchronous condition. In a second experiment we showed that this is also the case when a fake body is presented in
front of them and stroked synchronously but less when an object is presented.
For more details please see our
paper (supplementary materials available
here).
Q. Regarding, specifically, this experiment; how much time (if any) were subjects provided to familiarize
themselves with the virtual reality equipment and interface during the training period? Was this length of time fixed,
or did it vary between individual subjects?
A. Our subjects were not trained before the experiment. We explained the set-up to all subjects in detail and all of
them could wear the HMD before for a few minutes in order to familiarize with the 3D image and the rather surprising
effect of seeing themselves in front of them. We did not measure time but tried to do it exactly in the same way for
each subject. After the experiment, of course, the subjects were allowed to play around with the device, test the effect
of the time lag etc.
Q. Considering the average age of the subjects who participated in this experiment (23.1 +/- 4.4 SEM); what
influence, if any, do you feel the subjects' prior video game habits may have had on how they responded/adapted to
the virtual reality interface? Would you expect different results if the average age of these subjects had been
significantly greater (or less than) 23.1 +/- 4.4 SEM?
A. We did not systematically ask about gaming habits of our subjects even though this is a really interesting research
question. To test it, we would need a bigger subject group and maybe also pre-select a group of subjects that has a lot
of experience with gaming and contrast it to a group without any experience. Nevertheless we can assume that our
experimental set-up was a really new experience for all of the subjects, even for gamers, since they see themselves in
front of them in 3D through a HMD and we mainly manipulated tactile information, which is not often included in video
games. I would expect that different age-groups react differently, but this has first to be tested.
Q. Having completed this experiment; do you feel that your results have provided you with more answers, or
inspired you to ask more questions, regarding the phenomenon you had initially sought to study? Have these results
influenced the direction in which you see your research heading in the immediate future?
A. Rather the latter. Even though we saw in this experiment that more global aspects of bodily self can be manipulated
in healthy subjects, there are a lot of open questions (and as you mentioned, more then before), like e.g. which brain
mechanisms are underlying such illusions, what strengthens and weakens the illusion and a lot more interesting
questions that we are trying at the moment to investigate with new experiments.
Q. What advice would you have for an undergraduate student interested in questions concerning
'self-consciousness', and what do you feel is the general sentiment within the academic community toward research
focusing on such questions?
A. It is true that it is still relatively uncommon to investigate neuroscientifically questions about the self
that have traditionally rather been investigated by other disciplines such as philosophy. Nevertheless there is a
growing group of researches - often with a very interdisciplinary background - interested in similar
questions. Neuroscience is a very dynamic research field and a lot of interesting questions come from other disciplines
and were successfully integrated in neuroscience (e.g. neuroeconomics, neurotheology) even though they might have
been observed skeptically in the beginning. I would advice undergraduate student to study what they are interested in (even if it
something uncommon like the self) and not too much care about it is enough accepted in the community. As long as
they are convinced of what they do they will always find a niche in this - as I mentioned already - dynamic field of
neuroscience.
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