30 September 2013

An early morning just-before-work shave seems to be a trivial activity, yet how can you be sure it is yourself that you are shaving?

Although there’s an intuitive response to this daft question, the mechanisms underlying self-recognition are complex and elaborate. Children’s understanding of mirrors comes fairly late in development (between months 15 and 24) and can show striking disparities. A child can recognise herself, passing the mark test (reaching to a trace of paint that is only noticeable when looking in a mirror), and then suddenly ask why ‘she’ is wearing the same jacket as hers. Passing the mark test might certainly be a good index of self-recognition, but failing the mark test is no evidence to the contrary.

Interestingly, the ability to recognise oneself in a mirror can be lost after brain damage and is called mirrored self misidentification (a delusion in which patients perceive and conceive their reflection – usually in a mirror, but it has also been observed in ponds or windows – as an embodied stranger). In addition, healthy adults have all kinds of misconceptions about mirrors, so it is fair to say that the human brain is not really fine-tuned for this strange piece of optical-technology (remember the tale of Narcissus?). Recognising oneself in a mirror probably requires the convergence of several cognitive skills. There is no ‘self-recognition’ module. These abilities, for example: visuospatial coordination; visuo-kinesthetic integration; theory of mind, can develop in parallel, sequentially and/or hierarchically (i.e. one might be needed for another to appear). For instance, experimental evidence shows that tactile stimuli that are seen on another hand/body/face but at the same time felt on one’s own body induce an experience of ownership (this rubber hand is mine) or identification (this is my body/face). The same goes for motion: something moving in synchrony with our own movements can be learned to be self-attributed.

What else happens when something goes awry in the brain? An interesting group of patients can have complex bodily hallucinations, where one can see one’s own body in front of oneself (like a sort of a hologram); perceive the environment from a perspective external to one’s physical body, usually elevated, and see one’s body back in, for example, one’s bed; or even switch perspectives between one’s physical body and a hallucinated body. Sometimes, multiple bodies are perceived, with the patient not necessarily considering them as ‘self’, but still feeling a strong attraction and relation to them. In addition, other patients can feel as though somebody is standing right behind them, moving in the same way, although no one is there. These manifestations seem to reflect a deficient mechanism by which the brain mis-localises or duplicates different components of the representations of our bodies.

The act of depicting oneself/others visually or verbally is even more complex. It is not only visual features and bodily information that should be taken into account here, but also emotional aspects (memories, feelings, beliefs). Perceiving, imagining one’s body and depicting it are not necessarily based on the same mechanisms. Patients with eating disorders perceive their bodies and draw themselves differently from how they are seen by others. Curiously, if asked to point to the tips of your fingers, knuckles and the wrist while keeping your hand under the table you will get quite a distorted picture of your hand (e.g. underestimation of finger length, overestimation of hand width). You will, however be very accurate in judging whether an image of a hand is wider or narrower than your own. Such observations show a difference between the consciously perceived and implicitly stored body image. Also, subtle differences in the image of one-self modulate self-perception and self-representation. A mirror-reversed image of one’s face is more familiar than a non-reversed view. Both artists and non-artists seem to prefer self-portraits showing their left side. In the general population the detail of self-portraits seems to change with age. And finally, when encountering yourself in a dream, no visual resemblance at all is needed for you to never doubt that the character was you until waking up (to yet another early-morning shave).

For more information about Echo, the exhibition, and Mark Boulos, please visit the exhibition project page. This article was first published by the Wellcome Trust on their excellent blog. 

The development and production of Echo has been supported by the Wellcome Trust. The presentation of Echo has also been supported by Mondriaan Fonds, Pro Helvetia, and The Stanley Thomas Johnson Foundation. Echo was commissioned and produced by Forma in association with FACT, with development and production supported by The Wellcome Trust.