Abstract # 77:

Scheduled for Thursday, June 18, 2015 06:00 PM-08:00 PM: (Cascade AJBCD) Poster Presentation


USING A TOOL: IMPACT OF DEGREES OF FREEDOM ON TERMINAL PERFORMANCE BY TUFTED CAPUCHIN MONKEYS (SAPAJUS SPP.)

D. M. Fragaszy, J. Lukemire, E. R. Cruz, S. Villareal and M. C. Kelley
University of Georgia, Department of Psychology, Athens, GA 30602-3013, USA
line
     Humans discover the affordances of objects through action and control multiple degrees of freedom when using a tool. We examined if capuchin monkeys (N = 4) displayed these characteristics while using a hoe tool to retrieve a token. The handle of the tool was variously configured as a single rigid segment, two segments with one planar joint, or three segments with two (orthogonal) planar joints. From video playback, we coded the movements of the tool and actions on the handle for a subset of 20 trials (out of 40) per condition in the final phase of testing, following more than 100 trials of practice with each condition of the handle. Three monkeys retrieved the token effectively (median= 5.5 actions/trial, pooled conditions). These monkeys used the rigid tool conventionally but allowed the head of the tool to rest horizontally in 83% of trials in the jointed conditions. The fourth monkey maintained less control of the tool and token in all conditions (median= 9 actions/trial) and didn’t use the tool differently across conditions. Unlike humans, the monkeys’ mastery of this task reflected accommodation of action to the features of the tool rather than active control of the degrees of freedom of the handle. Future analyses will consider behavior accompanying practice with the tool from initial presentation to mastery. Supported by NIH – HD060563