>The elephant in the room, when it comes to the social brain hypothesis, is that plenty of herd animals (or school fish) exist in massive groups without needing

>The elephant in the room, when it comes to the social brain hypothesis, is that plenty of herd animals (or school fish) exist in massive groups without needing terribly big brains to cope. Group size and social complexity seem to be somewhat independent. Herds are a less complicated form of socialization. By contrast humans need to keep track of dozens of interpersonal relationships as a matter of personal survival. If you aren't paying attention, even the biggest toughest strongest man can be undone by 3 or 4 of his rivals banding together and attacking him as one. I'm reminded of one instance I read about several low status chimps all pouncing on an alpha who'd gotten too complacent and castrating him with their teeth, thereby ensuring he was permanently out of the running for leadership. Under such conditions, being clever is not just a nice-to-have - it is a matter of survival. The frugivore arguement might be totally valid too. As does the "natural" defense arguement - animals that have natural defenses like shells, quills, or other bodily forms of armor and defense tend to be less intelligent than creatures that lack such features. So it stands to reason that humans, as the species with the least equipped with natural defenses, would also be the cleverest of the bunch. But ultimately we just don't know. All we have is raw speculation.