title: Orientation toward humans predicts cognitive performance in orang-utans.
abstract: Non-human animals sometimes show marked intraspecific variation in their cognitive abilities that may reflect variation in external inputs and experience during the developmental period. We examined variation in exploration and cognitive performance on a problem-solving task in a large sample of captive orang-utans (Pongo abelii &P. pygmaeus, N = 103) that had experienced different rearing and housing conditions during ontogeny, including human exposure. In addition to measuring exploration and cognitive performance, we also conducted a set of assays of the subjects' psychological orientation, including reactions towards an unfamiliar human, summarized in the human orientation index (HOI), and towards novel food and objects. Using generalized linear mixed models we found that the HOI, rather than rearing background, best predicted both exploration and problem-solving success. Our results suggest a cascade of processes: human orientation was accompanied by a change in motivation towards problem-solving, expressed in reduced neophobia and increased exploration variety, which led to greater experience, and thus eventually to higher performance in the task. We propose that different experiences with humans caused individuals to vary in curiosity and understanding of the physical problem-solving task. We discuss the implications of these findings for comparative studies of cognitive ability.
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Switzerland.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Damerius
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Switzerland.
authors.forename: Sofia I F
authors.initials: SI
authors.lastname: Forss
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Switzerland.
authors.forename: Zaida K
authors.initials: ZK
authors.lastname: Kosonen
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Switzerland.
authors.forename: Erik P
authors.initials: EP
authors.lastname: Willems
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Switzerland.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Burkart
authors.affiliation: School of Psychology and Neuroscience, University of St. Andrews, United Kingdom.
authors.forename: Josep
authors.initials: J
authors.lastname: Call
authors.affiliation: Department of Archaeology, Simon Fraser University, Burnaby, BC, Canada.
authors.forename: Birute M F
authors.initials: BM
authors.lastname: Galdikas
authors.affiliation: Department of Education and Psychology, Freie University Berlin, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Liebal
authors.affiliation: Leipzig Research Center for Early Child Development, University of Leipzig, Germany.
authors.forename: Daniel B M
authors.initials: DB
authors.lastname: Haun
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Switzerland.
authors.forename: Carel P
authors.initials: CP
authors.lastname: van Schaik
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005106:Exploratory Behavior; D006801:Humans; D057080:Pongo abelii / Q000502:physiology*; D011148:Pongo pygmaeus / Q000502:physiology*; D011340:Problem Solving