A famous psychological experiment in the 1980s seemed to prove that the Brain "decides" to take actions before the conscious mind makes the choice to do so, and the decision we think we're making is only a rationalization after the fact:
Many experts in the field have reservations about this "proof" and have pointed out flaws in that interpretation of the results. A Wikipedia article goes into great detail about this experiment and other aspects of the "free will" issue in psychology:The Neuroscience of Free Will
There's also a psychological theory that the "self" we think we have or are is an Illusion, a trick the brain plays on itself. For one thing, our concept of our own identity arises from continuity of memory, an imperfect process riddled with gaps and reconstructions.
Here's one analysis of that issue:The Illusion of the Self
The author of this article, Sam Wolfe, summarizes cognitive scientist Bruce Hood's thesis that our "selves are generated by our brain in order to make sense of our thoughts and the outside world: both ‘I’ and ‘me’ can be thought of as a narrative or a way to connect our experiences together so that we can behave in an biologically advantageous way in the world." Wolfe endorses this position and cites support for it dating back many centuries, to 18th-century philosopher David Hume and, much further, as a traditional tenet of Buddhism. What we think of as our "self" arises from the brain as a "narrative-creating machine." As Wolfe puts it, "Essentially, our brains are always thinking in terms of stories: what the main character is doing, who they are speaking to, and where the beginning, middle, and end is; and our self is a fabrication which emerges out of the story-telling powers of our brain."
I wholeheartedly agree that the creation of stories is an essential aspect of the human brain, part of what makes us human. I can't agree with people such as Bruce Hood and Sam Wolfe, however, on their insistence that the narrative of a unified self doesn't correspond to reality. We visualize the self as a little cartoon person at a control panel somewhere in our head, directing the subordinate brain functions, or maybe, as in the animated film INSIDE OUT, a small committee of persons in a control center making executive decisions. Only a metaphor, of course, but regarding the singular self as an illusion seems to generate an intractable problem.
Since, as Hood and Wolfe acknowledge, "everyone experiences a sense of self – a feeling that we have an identity," if this sense of self is an illusion, a construct the brain creates to enable us to function in everyday life, who is the "us" believing the illusion? This theory seems to lead to an infinite regress of "selves" being fooled. Also, it seems to me a not-insignificant objection that it's impossible in practice to live as if one believes no actual self exists, or not for long anyway. And, again, who's doing the believing?
Margaret L. CarterCarter's Crypt