One difference between non-human primates and humans is that humans have a wide variation in the closeness of relationships, from celebrities you have never met

One difference between non-human primates and humans is that humans have a wide variation in the closeness of relationships, from celebrities you have never met but hear about occasionally on the news, to a soul-mate you know everything about. Presumably, the more intimate the relationship, the more cortical real-estate is taken up with information about that person. Non-human primates have their troop; certainly there's variation in relationships within that troop, but it's still just one troop of finite size. So, what this means in the context of humans is that Dunbar's number is very much dependent on the closeness of the relationships you're dealing with. Co-workers are different from close friends are different from comrades-in-arms. Someone who's up on pop culture (i.e, not me) may be able to tell you something about a couple hundred actors, athletes, politicians and so on, in addition to their personal acquaintances. Are those people included in their "Dunbar group"? If not, then where do you draw the line? It really is a problem of defining what, exactly, Dunbar's number means for humans.