Seeing choice-making as the work of a conscious agent is a vast over-simplification. It’s way more accurate to see it as an argument between the various organs of the brain, most of which happens at a subconscious level, with one of them eventually prevailing. Once that has happened, the story-writer function of the left hemisphere cranks out a story about how the conscious “I” made this or that choice, when in fact there was no “I” present when the actual choice was being made.
It’s kind of like a Supreme Court decision. One can speak of the Court as a unitary body and look at the final decision that it hands down. From that perspective the Court appears to be an agent. But as we know, the Court is not typically unitary at all; it’s a collection of competing points of view each trying to make the most compelling argument. One of the justices then gets to write what goes down in the record as the opinion of the Court, but “the Court”, as an entity, didn’t make the decision at all. It just lays claim to the prevailing opinion of the arguing factions.
The cast of characters engaged in the argument in the brain is more divers than the Court. In making even simple choices, like which cereal to buy, the first brain organ to engage is the nucleus accumbens, which is essentially the brain’s “wanting” organ. The nucleus accumbens, we should note, is not subject to our conscious control. It just pronounces its desires independently of any conscious thought process. Then the insula, as the brain’s voice of apprehension, will weigh in with the negative argument of possible painful consequences. The prefrontal cortex contributes the rational side of the argument, calculating what the available data would recommend.
A neurologist watching all of this activity on an fMRI imager can accurately predict the outcome of a simple decision like this by seeing which of these organs is the most active. If the insula shouts down the other organs, than is it “I” who decided that the risks of a course of action were just too great, or was it the insula? I can’t change my insula, so to what extent is it “me”? We tend to identify more with the voice of the prefrontal cortex, but why should that be? It’s very often not the dominant voice in the argument.