Use of multiple-alternative matching-to-sample in the study of visual search in a chimpanzee (Pan troglodytes).

Visual search in a chimpanzee (Pan troglodytes) and in humans (Homo sapiens) were compared under the multiple-alternative matching-to-sample (MTS) procedure, in which a sample stimulus was followed by one positive (target) and several negative comparison stimuli (distractors). Reaction times in the chimpanzee were affected by the number of distractors, the target-distractor similarity, and the uniformity of search display. Similar results were also obtained from humans and suggest that the performance by the chimpanzee may involve the same visual information-processing capabilities as those required in the human visual search performance. The multiple-alternative MTS is useful for studying various visual perceptual-cognitive abilities of animals including chimpanzees.