The sense of self has multiple components. To begin with, there is the ability to recognize one’s own face and body and to know what those body parts are doing at any given moment. There is also the sense of ownership—you perceive your body as belonging to you—and the sense of agency: you feel responsible for your own movements and actions. And at the highest level, there is the awareness of one’s own emotions and the ability to link disparate life experiences to a stable self-image.
Brain malfunctions can disrupt any of these processes. We have seen how depression and mania can derail a stable self-image, but other aspects of self are equally vulnerable. There are people, for example, who function pretty much normally except that they do not recognize themselves in a mirror. Others have trouble tracking the movements of their bodies. Some may even disown one of their limbs [see “Amputee Envy,” by Sabine Mueller; Scientific American Mind, December 2007/January 2008].
This article was originally published with the title Me, Myself and I.