Tyler Cowen points me to a PDF, Religious Belief Systems of Persons with High Functioning Autism, which has some fascinating results on the religiosity (or lack thereof) of people with high functioning autism. I've seen speculation about the peculiar psychological profile of atheists before in the cognitive science literature, and there's a fair amount of social psychological data on the different personality profile of atheists (e.g., more disagreeable). But there hasn't been a lot of systematic investigation of the possibility that autistic individuals are more likely to be atheist because they lack a fully fleshed "theory of mind," which would make supernatural agents, gods, more plausible. You can read the whole paper yourself, but these two figures are the most important bits:
These two figures illustrate two results: 1) Among two equivalent demographic samples differentiated by autism diagnosis state, the high functioning autistics are much more likely to be atheists. 2) Among a sample of autistics and neurotypicals those who are atheists have the highest "autism quotient." I doubt this is going to surprise too many people. Additionally, we need to be careful about generalizing here. I think it seems likely that a huge proportion of high functioning autistics are atheists, but, that doesn't mean that a huge proportion of atheists are high functioning autistics (though a larger proportion than the general population). Social context probably matters as well. In a nation like Estonia being an atheist is a lot less deviant and nonconformist than in the United States. Estonian high functioning autistics might still be atheist, but a much smaller proportion of atheists in Estonia are going to be high functioning autistics. Finally, there's another group which I think exhibits many of the same tendencies as atheists in the United States: libertarians. Note: I am a libertarian-leaning atheist, in case anyone cares.