One might be tempted to assume that if the human specie evolved as so blatantly non-Bayesian, yet survived and took over the world, then Bayesianism is probably incorrect. Because if it was, then surely any specie that would have evolved Bayesianism would have taken over the world instead of us. If we have this in mind, that should take care of the "be vs ought" fallacy, because what ought to be, would be.
I reject this argument however, mainly because Bayesian calculations are simply intractable. Even when they are, "Yikes! A tiger!!" is way more effective at Darwinism than the more explicit "Yellow, stripes, feline shaped, looking at me, big, danger so let's -AHRRGH CRUNCH GULP". And the fair amount of false positives that the emotional quick guess generates probably wasn't very harmful in the ancestral environment.
Because if it was, then surely any specie that would have evolved Bayesianism would have taken over the world instead of us.
Humans evolved a step towards being capable of Bayesian reasoning and we completely overthrew the natural order in an evolutionary instant. We should not expect to see close approximations of Bayesian thinking (combined with typical goal seeking behaviour) evolve because when a species gets vaguely close it becomes better at optimising than evolution is!
I have recently been corresponding with a friend who studies psychology regarding human cognition and the best underlying models for understanding it. His argument, summarized very briefly, is given by this quote:
I am having trouble synthesizing a response that captures the Bayesian point of view (and is sufficiently backed up by sources so that it will be useful for my friend rather than just gainsaying of the argument) because I am mostly a decision theory / probability person. Are these works of psychology and neuroscience really illustrating that human emotion governs decision making? What are some good neuroscience papers to read that deal with this, and how do Bayesians respond? It may be that everything he mentions above is a correct assessment (I don't know and don't have enough time to read the books right now), but that it is irrelevant if you want to make good decisions rather than just accept the types of decisions we already make.