Gc. Westergaard et Sj. Suomi, THE USE OF PROBING TOOLS BY TUFTED CAPUCHINS (CEBUS-APELLA) - EVIDENCE FOR INCREASED RIGHT-HAND PREFERENCE WITH AGE, International journal of primatology, 15(4), 1994, pp. 521-529
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.