You made some good points. I would only add that empathy and cooperation may be very low level mechanisms — while some older studies (Gilby) suggest that chimps share food only when other members of the group beg and harass them, a more recent study revealed that “the chimpanzees decide when to share food based on the likelihood that this favor will be returned in the future […] or, in case of sharing after group hunts, sharing of meat is returning the favor for helping out.” I.e. when they catch a monkey, only hunters eat and they won’t share even with alpha of the group if he was not a part of the hunting group or is not considered ‘a friend’. The folks conducting that research also “found higher oxytocin levels after both hunting and sharing [which] adds to the idea that oxytocin is a key hormone involved in cooperation in general,” as oxytocin plays a strong role in lactation “and is generally involved in social behavior and bonding.” But the researchers also clearly state that these finds are only “emphasizing the high variation in cooperation across chimpanzee populations.”
So as it seems, the jury is still out. At least in terms of why chimps cooperate (not whether they do cooperate because that obviously makes their chances for survival higher). Still, it would be interesting to know how that very learning you mention, which would be essential for “[cooperative] behaviour being transmitted across generations”, is dependent upon the genetic makeup of an individual. Can you imagine if humans stopped cooperate? After all, even the wealthy are able to be on “the top” only because they cooperate with like-minded people.
