The point is more that the fitness occurs on a net-basis. The more-fit traits outweigh the unfit traits. It is equally possible that humans as a species or su

The point is more that the fitness occurs on a net-basis. The more-fit traits outweigh the unfit traits. It is equally possible that humans as a species or sub-groups of humans are fit _despite_ irrationality as opposed to irrationality being adaptive. I suspect, however, that irrationality is actually a collection of a wide variety of cognitive traits and heuristics, some helpful in some circumstance, some not helpful, and these are not only situational but also vary by degree.