I'm a graduate student in cognitive science doing work on people's explanations and learning, particularly having to do with natural selection.
Often, students misunderstand natural selection as a "goal-directed" process, one in which organisms are directed to adapt towards beneficial traits. This kind of thinking can be tempting, since most evolved traits are beneficial in obvious and straightforward ways.
However, I'm very curious about traits whose benefits are NOT at all obvious, and can only be understood under careful consideration of the evolutionary process.
An prototypical example would be the evolution of altruism, or of homosexuality. But I'm looking for more examples like these, and preferably ones that are more specific/concrete (e.g., the existence of a specific trait/behavior, rather than someone general like altruism).
Any help would be appreciated.