I remember the moment when I became an atheist.

I was reading Religion's Claim to Be Non-Disprovable, an uneasy feeling growing in my head, and then I reached the bottom of the article, stared at the screen for a couple of seconds, and got it.

"There is no God," I whispered. (Then I braced myself to be hit by a thunderbolt from the sky, so the belief was still paying rent, right to the very end).

No thunderbolt came. I tried again, a little louder. "There is no God."

It was...

kinda obvious, actually. I mostly felt disappointed in myself for needing someone to explain it to me, like I'd failed a test and hadn't even realized it was a test until it was too late. Friendly AI? Never would have figured that one out myself. But it shouldn't have taken Eliezer-level intelligence to point out that there's no one sensible in charge of the universe. And so - without a crisis of faith, without worry, without further drama - I changed my mind.

Over the last 6 months, I've changed my beliefs about a lot of things. I get the impression that's pretty standard, for a first read-through of the sequences. The interesting part is that it wasn't hard. After reading everything on How to Actually Change Your Mind, I'd expected letting go of beliefs I'd held my entire life to be a bit of an ordeal. It really wasn't. I didn't agree with the LessWrong consensus on every issue (I still don't), but whenever I came to agree (or to modify my position in that direction) I said so, and reevaluated the appropriate assumptions, and adjusted my model of the world, and then went on to the next article. 

When I started the Sequences, I was 16. I don't think I'm generalizing from one example in terms of my ease of accepting new ideas; when I've explained these concepts to other smart teenagers, they usually also get the implications immediately and change their mind without apparent difficulty. It may be that most people rarely change their mind, but teenagers - at least the teenagers I know - change their mind a lot. I've watched my friends change their mind on life-changing decisions - colleges, careers, religion - every couple of weeks. Eliezer writes in "We Change our Mind Less Often Than We Think":

once I could guess what my answer would be - once I could assign a higher probability to deciding one way than other - then I had, in all probability, already decided. 

I haven't asked my friends to specify the probability they'll make a given decision (typical people find this annoying for some reason), but I've routinely heard them express high levels of confidence in a choice, only to have made a totally different decision the next day.

There are both advantages and disadvantages to changing your mind easily, but I think it's worth looking at the reasons it's easier for younger people to change their mind, and whether they have any implications for changing your mind in general. I've identified a couple reasons why it seems to be easier for teenagers to change their mind:

• There is less social pressure to be consistent when you're younger.  Most adults I know remember switching their major four times in college, and switching which college they wanted to go to more often than that. Adults who change their career 4 times in 4 years are undesirable employees, indecisive, and probably untrustworthy; kids who do the same are taking advantage of all the opportunities available to them. 

Lessons for Rationalists: Social pressure to be consistent is one of the big reasons why people don't change their minds. Don't state opinions publicly if you'll later feel pressured to stick by them; ask yourself how much of your attachment to a belief is related to what other people will think of you; foster a community where changing your mind is expected and encouraged. I think LessWrong does really well at all of these.

• Kids have less invested in their beliefs. If you're married to a theist and raising your kids in the tradition of a particular religion, it's a lot harder to suddenly change your mind about the foundations of your life. Similarly, people who've already experienced the loss of people close to them seem to have a lot more invested in the idea that death is the natural cycle of life.

Lessons for Rationalists: It's been suggested before (as a way of avoiding the sunk cost fallacy) that you imagine you've been teleported into this life, and have to decide what paths to take (independent of what the person-who-used-to-be-here was doing with their life). Ask yourself what you have invested in your current beliefs and what you would give up if you changed your mind. Try to find a third alternative between rejecting everything you once believed and clinging stubbornly to a lie; those are rarely really the only options.

• The fewer Fully General Counterarguments you know, the harder it is to maintain a belief in the face of opposing evidence. It's easier to convince a regular religious person of atheism than a theistic philosopher; if you haven't heard all the arguments for atheism before, they seem pretty devastating; if you have already heard them, and built up an elaborate mental defense system, it's easier to ignore them. Knowing about biases can hurt people; knowing more in general seems to also hurt people, unless they first learn how to avoid motivated skepticism.

Lessons for Rationalists: We really should start teaching this stuff in elementary schools. The more people learn about rationality before they get good at clever arguments, the better the odds they'll internalize it. LessWrong has discussed this a fair bit, but not done a ton about it. If people agree this is important, I'm planning a couple more posts on outreach to teenagers.

What other explanations are there?

tl/dr: Changing your mind is easier when you're younger. When you want to change your mind, try thinking like a teenager; if you want to be involved in rationality outreach, teach kids.