Effects on the behavior of infant common marmosets (Callithrix jacchus) of separation from caregivers and of drug-induced reduction in caregiver responsiveness

Abstract

The effects of separating 4-week-old twin marmosets for 8 days from their families are compared with the effects of leaving 4-week-old infants with their families, but reducing the responsiveness of their caregivers for 8 days by administration of the tranquilizer fluphenazine decanoate. Both treatments reduce infant mobility, abolish play, and increase the time that infants spend with each other. During the period after the termination of the treatment, both treatment groups continue to play and move less than controls, and try to climb onto the mothers more frequently. These results are consistent with the hypothesis that the principal factor precipitating disturbed behaviors in infant monkeys subjected to long-term separation is disruption of the infant-caregiver relationship rather than the separation itself. Some post-treatment differences occur between separated and tranquilized groups. Notably, reunion after separation appears to involve a marked readjustment of the behavior of all family members to the return of the infants, whereas withdrawal of the tranquilizer does not.