i like to see studies like this that explain evolved traits in terms of how we're imperfectly assembled. fighting against the creationists and intelligent design people is really as easy as pointing to the countless examples of where evolution produced results that seem like horrific mistakes - and would be if "mistake" made any sense in the context of a random, unguided process with no end.

....but biologists have the same problem as the rest of the teleologists. they want everything to have a causal relationship, as though selection is as perfect as a deity would be.

there isn't a brilliant reason. evolution just done fucked up on this one.

http://www.scientificamerican.com/article/sexual-cannibal-spiders-may-have-poor-impulse-control