PRIMATE VOCALIZATIONS DURING SOCIAL SEPARATION AND AGGRESSION - EFFECTS OF ALCOHOL AND BENZODIAZEPINES

The most common group of squirrel monkey vocalizations, peeps, are emi tted during different social situations including social separation, a ffiliative interactions, feeding and aggressive confrontations. The pr esent experiments investigated whether peeps and other vocalizations e mitted during different social contexts are pharmacologically altered in a similar manner. First, vocalizations were characterized during (1 ) social separation in juveniles, and (2) ''resident-intruder'' aggres sive confrontations between dominant monkeys from different social gro ups. Then, the effects of alcohol (EtOH) and the benzodiazepine chlord iazepoxide (CDP) on vocalizations during social separation and during aggression were examined. Isolated juveniles emitted only one type of call, the isolation peep. Resident monkeys primarily emitted peeps, bu t also emitted cackles, chucks, noisy calls and pulsed calls. Aggressi ve peeps were similar in structure and frequency (kHz) to isolation pe eps, but were shorter in duration. At the same doses, both CDP (0.3-3 mg/kg) and EtOH (0.1-1.0 g/kg) reduced explosive motor behaviors and i solation peeps in juvenile monkeys during social separation and increa sed threat displays and aggression peeps in resident monkeys during co nfrontations with an intruder monkey from a different social group. Th us, similarly structured vocalizations that were emitted during social separation and aggression were very sensitive to EtOH and CDP, but th e social context determined the direction and magnitude of effects.