title: Sequential planning in rhesus monkeys (Macaca mulatta).
abstract: In the current study, we examined the planning abilities of rhesus monkeys (Macaca mulatta) by training them on a five-item list composed of coloured photographs and then testing them on switch and mask trials. In contrast to previous studies where monkeys made responses using a joystick, in the current study, monkeys made responses directly to a touch screen. On switch trials, after a response to the first list item, the on-screen positions of two list items were exchanged. Performance on trials in which the second and third list items were exchanged was poorer compared to normal (non-switch) trials for all subjects. When the third and fourth items were exchanged, however, only one subject continued to show performance deficits. On mask trials, following a response to the first item, the remaining items were covered by opaque white squares. When two items were masked, all four subjects responded to each masked item at a level significantly above chance. When three items were masked, however, only one subjected was able to respond to all three masked items at a level significantly above chance. The results of the present study indicate that three of our four monkeys planned one response ahead while a single monkey planned two responses ahead. The significance of these findings is discussed in relation to previous studies on planning in chimpanzees and monkeys.
authors.affiliation: Department of Psychology, University of Otago, PO Box 56, Dunedin, New Zealand. scada298@student.otago.ac.nz
authors.forename: Damian
authors.initials: D
authors.lastname: Scarf
authors.forename: Erin
authors.initials: E
authors.lastname: Danly
authors.forename: Gin
authors.initials: G
authors.lastname: Morgan
authors.forename: Michael
authors.initials: M
authors.lastname: Colombo
authors.forename: Herbert S
authors.initials: HS
authors.lastname: Terrace
mesh_terms: D000818:Animals; D003071:Cognition; D006801:Humans; D007858:Learning; D008253:Macaca mulatta / Q000523:psychology*; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time