title: Experimental field study of hand preference in wild black-horned (Cebus nigritus) and white-faced (Cebus capucinus) capuchins: evidence for individual and species differences.
abstract: In this experimental field investigation, we compare the degree to which wild capuchins in Brazil (Cebus nigritus) and Costa Rica (Cebus capucinus) exhibit individual- and population-level handedness during three visually-guided tasks. These tasks required reaching to remove a large leaf covering a hidden food reward, seizing the food reward, and manipulating a tool (pulling a wooden dowel) in order to obtain access to an embedded food reward. Studies in some populations of captive capuchins indicate evidence for both individual hand preferences and population-level handedness. In this study, six of eight wild C. capucinus and six of seven wild C. nigritus exhibited a significant hand preference during individual tasks, but no individual exhibited a consistent preference across all three tasks. Task-specialization, or the tendency for most individuals in the same group or population to use the same hand to accomplish a particular task, also was evaluated. Cebus nigritus showed a significant bias toward the use of the right hand in removing the leaf. Although the number of individual capuchins in both species that manipulated the dowels was limited (N = 7), each individual that manipulated the dowels in eight or more instances had a positive handedness index, suggesting a greater use of the right hand to accomplish this task. Overall, our results provide preliminary support for individual- and population-level handedness in wild capuchin monkeys.
authors.affiliation: Department of Anthropology, University of Illinois, Urbana, IL 61801, USA. p-garber@uiuc.edu
authors.forename: P A
authors.initials: PA
authors.lastname: Garber
authors.forename: D F
authors.initials: DF
authors.lastname: Gomes
authors.forename: J C
authors.initials: JC
authors.lastname: Bicca-Marques
mesh_terms: D000818:Animals; D002428:Cebus / Q000523:psychology*; D002755:Choice Behavior; D005260:Female; D007839:Functional Laterality; D007206:Individuality; D008297:Male; D011340:Problem Solving; D013045:Species Specificity; D053001:Tool Use Behavior