Dunbar’s number and how speaking is 2.8x better than picking fleas

Dunbar actually doesn’t say that we devote “grooming time” to the whole social group of 150. Rather he says that the 150 is made up from welding together much smaller “primary networks”: coalitions, friendship groups. Intensive grooming (language, for humans) is reserved for close friends. Our intimate group is very small, averaging just five.