 At this point, most of the observed behaviors in animals, like those observed by Imanishi, were related to survival in some way.The first evidence of apparently arbitrary traditions came in the late-1970s, also in the behavior of primates.At this time, researchers McGrew and Tutin found a social grooming handclasp behavior to be prevalent in a certain troop of chimpanzees in Tanzania, but not found in other groups nearby.