You answering the assumption that I called you out on would be relevant. Namely that Eve must have repeated what the snake said to Adam.
Yes, she must have. If he didn't hear the serpent directly then she must have told him of her encounter. Nothing else makes sense. It's highly unlikely he took a bite for no good reason other than she handed him the apple. "Mmm, yum yum." He knew which tree she plucked the apple from and would have been horrified unless he thought there was something to be gained from it, and not that it just looked scrumptious.
^ The implications of that are critical. If Adam was not deceived, either by the serpent or Eve, why did God kick him out of Paradise? Yes, he ate from the tree he was forbidden to, but did he know? If he did what would have been his motivation?
Still it doesn't give us the incentive to play psychologist
I don't think I'm playing psychologist, but if I am I believe I have good incentive for it. I'm trying to understand his reason for taking a bite. Why would he be such a fool to disobey God unless he thought there was something to gain by it? God told him he would surely die if he ate from the tree. That was a big risk he took. He must have thought there was a big payoff to take it. Either that, or he didn't know from what tree he was eating.
There really aren't that many options for what motivated him.