title: Learning and generalization of a two-dimensional sameness-difference concept by chimpanzees and orangutans.
mesh_terms: D000818:Animals; D003118:Color Perception; D003210:Concept Formation; D003463:Cues; D004193:Discrimination Learning; D005247:Feeding Behavior; D005260:Female; D005556:Form Perception; D005793:Generalization, Psychological; D015186:Hominidae; D006799:Housing, Animal; D008297:Male; D002679:Pan troglodytes; D011340:Problem Solving; D012201:Reward; D014163:Transfer, Psychology