The Bactra Review   Brainchildren
Considering the degree of close cooperation our ancestors would have needed to survive, I rather suspect they were subject to selection pressure for folk-psychological predictability. Clearly, I think, if you depend on your fellows knowing what you're up to, and they're using scheme F to do that, you're more likely to survive if F is a good predictor of your behavior. Of course, if there's variation in F as well, then the variants which do the best job of predicting behavior (including yours) will be favored. This is a rather benign evolutionary arms-race.