title: Gorilla ( Gorilla gorilla gorilla) and orangutan ( Pongo abelii) understanding of first- and second-order relations.
abstract: Four orangutans and one gorilla matched images in a delayed matching-to-sample (DMTS) task based on the relationship between items depicted in those images, thus demonstrating understanding of both first- and second-order relations. Subjects matched items on the basis of identity, color, or shape (first-order relations, experiment 1) or same shape, same color between items (second-order relations, experiment 2). Four of the five subjects performed above chance on the second-order relations DMTS task within the first block of five sessions. High levels of performance on this task did not result from reliance on perceptual feature matching and thus indicate the capability for abstract relational concepts in two species of great ape.
authors.affiliation: York University, 4700 Keele Street,Toronto, ON M3J 1P3, Canada. jxv9592@louisiana.edu
authors.forename: Jennifer
authors.initials: J
authors.lastname: Vonk
mesh_terms: D000818:Animals; D003071:Cognition; D003118:Color Perception; D005260:Female; D006071:Gorilla gorilla / Q000523:psychology*; D008297:Male; D011148:Pongo pygmaeus / Q000523:psychology*; D013647:Task Performance and Analysis