Abstract # 51:

Scheduled for Thursday, August 17, 2006 04:00 PM-04:15 PM: Session 6 (Regency East #3) Oral Presentation

The link between hand preference, response to novelty, and fearfulness in captive marmosets (CALLITHRIX GEOFFROYI)

S. N. Braccini and N. G. Caine
California State University, Department of Psychology, San Marcos, CA 92096, USA
     The consistent use of one hand over the other (handedness) is a form of laterality that may reflect hemispheric specialization. In primates, hemispheric specialization has also been observed for a variety of other traits; fearfulness, for instance, has been linked to right hemisphere function. If laterality is a reflection of general dominance of one hemisphere over the other, other specializations associated with that hemisphere might also be dominant in an individual. In our study we used ecologically valid situations to test the hypothesis that right-handed Geoffroy’s marmosets are bolder, and in turn, less fearful than left-handed marmosets. Marmosets living in one of two groups (N=18) were scored for their willingness to approach, sniff and taste novel foods. In a second study the duration of marmosets’ “freeze” responses were scored following the playbacks of hawk calls. Hand preferences were then determined based on a minimum of 50 instances of spontaneous hand use in everyday feeding situations. Randomization tests were used to compare marmosets who were strongly right handed (N=7) to those who were strongly left handed (N=5). As predicted, the right handed individuals were more likely than left-handed individuals to approach (p<.05) and to sniff (p<.05) novel foods. The latter also froze longer after hearing hawk calls (p=.05). These data support the notion that handedness might correlate with other behavioral propensities in nonhuman primates.