New Scientist is carrying this article detailing recent findings about the relationship between large brains and certain types of primate behavior. Turns out, larger brains confer the ability to be a sneaky bastard, which is advantageous in a complex social network such as the ones that nearly all primates live in. Includes this amusing example:

Byrne [one of the authors of the study] has himself observed a young baboon dodging a reprimand from its mother by suddenly standing to attention and scanning the horizon, conning the entire troop into panicking about a possible rival group nearby. "We were rather shocked that baboons could do anything quite as subtle as that," he says.

Seems like primate children are alike no matter what species they belong to, no?