Behavioral and autonomic responses to peer separation in pigtail macaque monkey infants

Abstract

Brief maternal separations of young nonhuman primates have been used extensively to study the behavior and physiology of attachment, loss, and bereavement. The physiological responses to the loss of alternative attachment figures, such as peers, is less well documented in nonhuman primates. This study examined both autonomic and behavioral responses of peer-reared pigtail macaque infants to separation. Eight infants were removed from their mothers at birth and reared in four peer pairs. At 6 months of age, each monkey was implanted with a multichannel biotelemetry device which transmitted heartrate, body temperature, EEG, EMG, and EOG. Blood was collected twice weekly for immunological assessment. Behavioral and physiological data, including sleep, were collected for 1 week of baseline, 2 weeks of separation, and 1 week of reunion. Behavioral and physiological results indicated agitation but not depression following separation from their peer attachment figures. We found reduced mitogenic responses to pokeweed consequent to peer separation, suggestive of altered B-cell function. REM variables were the only sleep measures affected by the separation, and were suggestive of agitation but not depression.

Time‐dependent effects of peer separation on lymphocyte proliferation responses in juvenile squirrel monkeys

“…The results of this research support previous findings in rats (Jessop & Bayer, 19891, macaque monkeys (Boccia et al, 1989;Laudenslager et al, 1982;Reite et al, 1981), and human beings (Bartrop, Lazarus, Luckhurst, Kiloh, & Penny, 1977;Schliefer, Keller, Camerino, Thornton, & Stein, 1983) indicating that the psychological disturbance associated with separation and loss can impair cellular immune function. They also suggest that this impairment can occur quickly, within three hr of separation in the squirrel monkey, but that it is transient, lasting less than a week.…”

“…Thus, while there was a dose-dependent relationship between lymphocyte proliferation and mitogen concentration, it was not a straightforward one. The observation that some concentrations of mitogen activate lymphocytes more effectively than do either greater or lesser concentrations is common (Laudenslager et al, 1982;Kiecolt-Glaser et d., 1984;Glaser et al, 1985;Kiecolt-Glaser et al, 1987;Boccia et al, 1989;Laudenslager et al, 1990). In our experiments, three concentrations of each mitogen were used in order to obtain a better estimate of the concentration which was optimal for this particular primate species.…”

Social context and reaction to separation in peer-reared pigtail macaques: Some preliminary observations

“…MINEKA et al, 1981;SUOMI et al, 1970), while others (e.g. ANDERSON, 1983;BOCCIA et al, 1989;ERWIN et al, 1971;MAXIM, 1980;MINEKA et al, 1985) report agitation but no depression in response to peer separation. Those studies which find the second, depression stage of separation in peers typically employ repeated separation paradigms.…”

“…Furthermore, little data are available on the impact of the social environment on peerseparation responses. In our laboratory, peer-reared pigtail infants who have been separated from their peer and housed alone show evidence of behavioral and physiological agitation, but not depressive responses to the separation experience (BoccIA et al, 1989;REITE, HARBECK, & HOFFMAN, 1981). In infant squirrel monkeys, this behavioral agitation response to separation from their peer is eliminated if they remain in their home environment with another familiar peer (HENNESSEY et al, 1982), again implicating the social environment in the response to separation.…”

Social development in nursery-reared pigtailed macaques (Macaca nemestrina)

“…185th, Beaverton, Oregon 97006. Reite et al, 1974Reite et al, , 1981Boccia et al, 1989;Laudenslager et al, 1990;Weeks et al, 1989;Gunderson et al, 1987Gunderson et al, , 1989Clarren et al, 1990Clarren et al, , 1992Morton et al, 1993].…”