Program-level transmission would predict the existence of different populations in which the majority of gorillas process the same plant species by means of different action sequences. Orangutans stringing up hammocks and washing dishes present a more convincing case. It seems unlikely that these apes received training for actions that humans would certainly rather not have them perform, such as siphoning fuel from a drum. The fact that this sort of imitation occurs in orangutans living with humans is significant. If sympathy varies with emotional closeness to the model, this has serious consequences for claims about imitation, or the absence thereof, in human-animal experiments.
Animals probably identify the easiest with the species they know best.
In the same way, rehabilitant orangutans and language-trained bonobos may see themselves as partly human. A group mate in distress, or engaged in a sexual or aggressive encounter may draw more intense and precise attention than the sight of a human experimenter with a new contraption. Journal of Comparative Psychology 110, 316-320. A hierarchical approach. Behavioral and Brain Sciences 21, 667-721.