THE USE OF PROBING TOOLS BY TUFTED CAPUCHINS (CEBUS-APELLA) - EVIDENCE FOR INCREASED RIGHT-HAND PREFERENCE WITH AGE

We examined hand preference in the use of tools by tufted capuchins (C ebus apella). We presented a colony of monkeys with an enclosed contai ner designed to accommodate the use of probing tools. Over an 8-month period, 13 monkeys used probes to extract sweet syrup from the narrow opening of the apparatus. Five monkeys exhibited bias toward use of th eir right hand and eight monkeys exhibited bias toward use of their le ft hand. Adult monkeys exhibited a greater percentage of right-hand pr eferent probing sequences than did juveniles. These results are consis tent with hypotheses that in tasks thal involve the use of tools, nonh uman primates exhibit strong lateral asymmetries at the individual lev el, a moderate left-hand bias at the population level, and increased b ias,with age toward use of the right hand.