from the limited work I have done with our sociopathic cousins the difference between us and the apes is what de Waal calls empathy, Hodobler and Wilson call eusociality and Chomskey calls LAD. I think we have a qualitative difference in how our brains work a organ of humanness most likely caused by a frame-shift mutation.
de Waal's latest book claims that empathy came from the primate world? Chimpanzees can behave with empathy. So can bonobos and other great apes. I've read Hodobler and Wilson's work on eusociality. I think it is true that we are eusocial and the other great apes aren't. I suppose I didn't list it because eusociality is a function of having complex language and the desire to teach and by taught etc. But point taken. I've never heard of Chomskey's LAD.
It is a complex eusociality and teach/taught are part of the same thing.(in my mind) on empathy I think the word requires a split cognitive empathy (the ability to figure out what the other guy is thinking/feeling) and emotional empathy (giving a shit about what the other guy things and feels). if one lacks cognitive empathy he is a aspie. lacking emotional empathy is sociopathy. The chimps I met have a bit of the first one and none of the second.