Global and local processing of visual patterns in macaque monkeys.

Human subjects generally perceive the global form of hierarchically organized visual patterns faster than the local form. To test whether macaque monkeys show a similar precedence for global processing, two monkeys were trained to discriminate either the global or local form of hierarchical visual patterns. The response time to discriminate the global form was shorter than that to discriminate the local form. Consistent patterns, in which the global and local forms were identical, were discriminated faster than inconsistent ones, in which the two forms were different from each other, both in discrimination of the global form and of the local form. Similar results were obtained in two human subjects who were subjected to the identical tests. The results suggest that, both in monkeys and humans, the global form is processed faster than the local form with a temporal overlap which allows bidirectional interactions between the two processes.