For some time now, I've been arguing that it's not possible for any individual to be a reliable witness to their own lives, to explain how and why they do what they do. However plausible the evidence and however sensitive the analysis.
Here's a nice description from an old debate in the letters pages of NS about Free Will that explains why:
'…If "I" equals my conscious self – let's call her the "brat" – my free will must be limited, because most of what goes on in my brain isn't directly available to the brat. The brat is full of herself, likes to think she's the whole story. From the point of view of the rest of the brain, the brat may be a party trick that got out of hand.
The brat disrespects the rest of my brain. It's where the grunge comes from. If it makes a good call, it's "just instinct". (The brat is selective in claiming responsibility, and frequently confuses labels with explanations.)
If "I" am my total self – body, brain and yes, brat – I probably do have some measure of free will. If the brat would calm down and try listening, perhaps she could get a better idea of how decisions are really made round here' (Marianne Vespry)
And of course the brat don't know – is in denial, maybe? – about the influence of others, so asking an individual about that is not going to be as much help as it seems either.