title: Cognitive differences between orang-utan species: a test of the cultural intelligence hypothesis.
abstract: Cultural species can - or even prefer to - learn their skills from conspecifics. According to the cultural intelligence hypothesis, selection on underlying mechanisms not only improves this social learning ability but also the asocial (individual) learning ability. Thus, species with systematically richer opportunities to socially acquire knowledge and skills should over time evolve to become more intelligent. We experimentally compared the problem-solving ability of Sumatran orang-utans (Pongo abelii), which are sociable in the wild, with that of the closely related, but more solitary Bornean orang-utans (P. pygmaeus), under the homogeneous environmental conditions provided by zoos. Our results revealed that Sumatrans showed superior innate problem-solving skills to Borneans, and also showed greater inhibition and a more cautious and less rough exploration style. This pattern is consistent with the cultural intelligence hypothesis, which predicts that the more sociable of two sister species experienced stronger selection on cognitive mechanisms underlying learning.
authors.affiliation: Anthropological Institute &Museum, University of Zurich, Switzerland.
authors.forename: Sofia I F
authors.initials: SI
authors.lastname: Forss
authors.affiliation: Anthropological Institute &Museum, University of Zurich, Switzerland.
authors.forename: Erik
authors.initials: E
authors.lastname: Willems
authors.affiliation: School of Psychology and Neuroscience, University of St. Andrews, United Kingdom.
authors.forename: Josep
authors.initials: J
authors.lastname: Call
authors.affiliation: Anthropological Institute &Museum, University of Zurich, Switzerland.
authors.forename: Carel P
authors.initials: CP
authors.lastname: van Schaik
mesh_terms: D000818:Animals; D000836:Animals, Zoo; D001522:Behavior, Animal; D003071:Cognition; D005260:Female; D007360:Intelligence; D008297:Male; D057080:Pongo abelii / Q000523:psychology*; D011148:Pongo pygmaeus / Q000523:psychology*; D013045:Species Specificity