To break up the awkward silence at the start of a recent Overcoming Bias meetup, I asked everyone present to tell their rationalist origin story - a key event or fact that played a role in their first beginning to aspire to rationality. This worked surprisingly well (and I would recommend it for future meetups).
I think I've already told enough of my own origin story on Overcoming Bias: how I was digging in my parents' yard as a kid and found a tarnished silver amulet inscribed with Bayes's Theorem, and how I wore it to bed that night and dreamed of a woman in white, holding an ancient leather-bound book called Judgment Under Uncertainty: Heuristics and Biases (eds. D. Kahneman, P. Slovic, and A. Tversky, 1982)... but there's no need to go into that again.
So, seriously... how did you originally go down that road?
Added: For some odd reason, many of the commenters here seem to have had a single experience in common - namely, at some point, encountering Overcoming Bias... But I'm especially interested in what it takes to get the transition started - crossing the first divide. This would be very valuable knowledge if it can be generalized. If that did happen at OB, please try to specify what was the crucial "Aha!" insight (down to the specific post if possible).
Some of my earliest childhood memories, age 4 maybe, are of Sunday School, enjoying the stories and the socializing, but being secretly astonished that the sweet little old ladies that ran the Sunday School made such a show of believing in their stories, of pretending they could actually communicate telepathically with a character in a story.
On reflection, I'm not so much surprised that I didn't accept the BS, but surprised that I knew instinctively not to question them about it and rock their boat.
But then, more recently I've started worrying that one of these days the mothership is going to come back and pick me up and debrief me. "What have you learned from over fifty years of living on this planet, among these people, as one of them?" And I'll have to admit I don't understand this species at all.
Well, I am utterly shocked that at such a young age you didn't even consider the possibility that God was real and that you could pray to him. Seriously, what gives? Where did this sense of distinction between fiction and reality come from? How did you distinguish the Bible from, say, History?