I have came across this short article by a neuroscientist: The Neurology of Self-Awareness:

What is the self? How does the activity of neurons give rise to the sense of being a conscious human being? Even this most ancient of philosophical problems, I believe, will yield to the methods of empirical science. It now seems increasingly likely that the self is not a holistic property of the entire brain; it arises from the activity of specific sets of interlinked brain circuits. But we need to know which circuits are critically involved and what their functions might be. It is the “turning inward” aspect of the self — its recursiveness — that gives it its peculiar paradoxical quality.

The argument, in summary, is as follows:

  1. It is believed that consciousness evolved in a social context, primarily as a way to better understand and be able to predict what other humans will do in certain situations.
  2. Mirror neurons (primarily in primates. but also have been found in birds) have the ability to “adopting another’s point of view”, activating not only when the individual itself is performing an action (for example), but also when watching another do it.
  3. It doesn’t seem like much a reach to assume that the development of mirror neurons arose due to humans (and other primates) being highly social animals: the ability to model (or simulate) other individuals and predict their actions must have proved to be very valuable.
  4. Evolution often takes advantage of pre-existing structures to evolve completely novel abilities. Evolving completely new functions or abilities is very hard: evolution, due to its nature, can usually only make changes very slowly, incrementally. For a complex new feature to appear, it must both be able to be developed step by step, and must be a response to extremely strong and persistent pressure. Therefore, evolution will “prefer” to re-use existing facilities.
  5. Therefore, one way that self-awareness could have evolved would be from “other-awareness” (empathy, predicting the behavior of others); in other words, awareness of others came first (to help navigate a complex social environment), and self-awareness evolved from that, perhaps as an unexpected “side benefit”.

From the article:

I suggest that self awareness is simply using mirror neurons for “looking at myself as if someone else is look at me” (the word “me” encompassing some of my brain processes, as well). The mirror neuron mechanism — the same algorithm — that originally evolved to help you adopt another’s point of view was turned inward to look at your own self. This, in essence, is the basis of things like “introspection”. It may not be coincidental that we use phrases like “self conscious” when you really mean that you are conscious of others being conscious of you. Or say “I am reflecting” when you mean you are aware of yourself thinking. In other words the ability to turn inward to introspect or reflect may be a sort of metaphorical extension of the mirror neurons ability to read others minds.

It is often tacitly assumed that the uniquely human ability to construct a “theory of other minds” or “TOM” (seeing the world from the others point of view; “mind reading”, figuring out what someone is up to, etc.) must come after an already pre- existing sense of self. I am arguing that the exact opposite is true; the TOM evolved first in response to social needs and then later, as an unexpected bonus, came the ability to introspect on your own thoughts and intentions.

Keep in mind though that evolutionary biology is highly controversial: trying to reason about why evolution “did” things is fundamentally problematic. Evolution does not design, and has no intent, and it is very easy to fall into the trap of thinking about it as if it did.

Having said that, I have to admit that this theory strongly appeals to me; it makes sense to me because it is so… pedestrian. We may have gained consciousness as a side effect! That, I think, is profoundly hilarious, and exactly the kind of thing I’d expect to happen in the kind of universe we inhabit. It shares a sort of a kinship with the idea of “Why do viruses exist? Because they can.”