[circuithunter]

There's actually quite a bit of evidence suggesting that brains, both behaviorally and mechanistically, are Bayesian [0].

As for your second point, assuming that humans are Bayesian, there are many reasons why people would have variability in their mathematical ability, including different priors and differences in the ability to estimate posteriors.

[0] https://scholar.google.com/scholar?q=brain+bayesian&hl=en&bt...