I’ve been reading a lot of interesting material on the “sense of self.” This phrase is not referring to our ego or mind (though it’s certainly related to it) but our sense of our physical self as it moves through the world. We tend to think that it’s perfectly obvious where “we” begin and end, but this seems to be a skill, learned at a very young age, which combines what we see, hear and touch with less overt sensory information such as information derived from our muscles and inner ear telling us where we are in space.

The brain maintains a kind of body map which keep track of our limbs, digits and even internal organs. When it’s working correctly, it’s a blessing. But when the body map gets out of sync with the body it can cause strange symptoms. The most obvious example is a phantom limb: a person with an amputated limb still “feels” the presence of the missing body part. And the inverse can happen. People can have a functioning limb, but because their internal body map does not recognize it (because of brain damage or whatnot) they feel like the limb does not belong to them. It’s an alien limb, and often its owners will request its amputation. Other people’s body maps will somehow construct a “twin” so that they feel they’re constantly being followed and mimicked by a possibly malevolent phantom.

I’ve experienced the sensation of a faulty body map. When, as a teenager, my penis grew to its full length of 9 inches (fully erect) I still, for some time, had the sensation of a smaller penis as might be possessed by an inferior man. It took some time for my body map to acclimate to the phenomenal volume of my phallus. But that’s neither here nor there…

Also related to our sense of self are specific types of neurons in the brain called mirror neurons. When you decide to pick up a cup of coffee, certain neurons in your brain fire, in essence ordering your arm to perform the action. However, some of those same neurons also fire when you watch someone else pick up a cup of coffee. So, in a sense, we are experiencing their action (though on a subconscious level.) Our body map is being extended to include people around us.

Now, I’ve often complained in this blog about the issues I’ve had with my vestibular system (the collection of membranes in the inner ear responsible for our sense of balance and motion in space) to little sympathy. Interestingly, it turns out that autistic children often have vestibular dysfunction. As a result, they have trouble integrating what they see and hear with where they are in space.

I wonder if we can take this observation a little further. A classic complaint about some autistic children is that they seem to have trouble discerning people from objects. For example, an autistic child will respond (as measured by MRIs etc.) to a picture of a person the same way they would to a picture of a chair. Is it possible that a child who never develops a functional vestibular system (e.g. where “I” am in space) is thus hindered in their ability to develop a sense of their physical self, and from there hindered in their ability to develop a psychological sense of self (e.g. ego or mind etc.) and from there develops no ability to recognize the other “selves” out there?

This idea is almost certainly an overreach — there’s more to our physical sense of self than just our vestibular system. And there’s lots more to autism than just vestibular damage. But it does hint at interesting concepts of how our awareness of our physical being (which we largely take for granted) interrelates with our psychological self (which we obsess over constantly.)