Why did consciousness evolve?

From David Barash, evolutionary biologist and professor of psychology at University of Washington.

"Brief explanatory excursion: it is a useful exercise to ask what brains are for. From an evolutionary perspective, brains evolved not simply to give us a more accurate view of the world, or merely to orchestrate our internal organs or coordinate our movements, or even our thoughts. Rather, brains exist because they maximise the reproductive success of the genes that helped create them and of the bodies in which they reside. To be adaptive, consciousness must be like that. Insofar as it has evolved via natural selection, consciousness must exist because brains that produced consciousness were evolutionarily favoured over those that did not. But why? One possibility is that consciousness gave its possessors the capacity to overrule the tyranny of pleasure and pain."

"Even more intriguing than its use as a facilitator of impulse control is the possibility that consciousness evolved in the context of our social lives. Human societies privilege a kind of Machiavellian intelligence whereby success in competition and co-operation depends on our evolved ability to imagine another’s situation no less than our own. That isn’t so much out of intended benevolence (although this, too, could be the case) but because such leaps of the imagination allow us to maximise our own interests in the very complex landscape of human societies. Thus, consciousness is not only an unfolding story that we tell ourselves, moment by moment, about what we are doing, feeling and thinking. It also includes our efforts to interpret what other individuals are doing, feeling and thinking, as well as how those others are likely to perceive us in return.[...] The more conscious our ancestors were, according to this argument, the more able they were to modify — to their own benefit — others’ impressions of them and, hence, their evolutionary success."

"It therefore appears at present that human beings, although probably not unique in possessing Theory of Mind, are nonetheless unusual in the degree of its sophistication, specifically in the extent to which they can accurately model the minds of others. It seems highly likely that those who possessed an accurate Theory of Mind enjoyed an advantage when it came to modelling the intentions of others, an advantage that continues to this day, and was an active ingredient in the evolution of human consciousness. And it is at least possible that the more conscious you are, the more accurate is your Theory of Mind, since cognitive modellers should be more effective if they know, cognitively and self-consciously, not only what they are modelling, but that they are doing so."