Meyer JS, Novak MA, Bowman RE, Harlow HF. Behavioral and hormonal effects of attachment object separation in surrogate-peer-reared and mother-reared infant rhesus monkeys. Dev Psychobiol 8: 425-435

Developmental Psychobiology (Impact Factor: 3.31). 09/1975; 8(5):425-35. DOI: 10.1002/dev.420080507
Source: PubMed


Mother-reared and surrogate-peer-reared rhesus monkeys were separated from their respective attachment objects at 6 months of age and tested for the following 9 weeks to determine their home-cage behavior and their pituitary-adrenocortical responses to stress. Both groups displayed a strong immediate behavioral response to separation which was characterized by increased vocalization, increased locomotion, and decreased self-play. However, the surrogate-peer-reared infants showed a subsequent recovery in their levels of self-play whereas the mother-reared infants instead developed stereotypic behavior patterns such as repetitive pacing. The 2 groups displayed similar plasma cortisol responses to weekly sessions in an apparatus equipped with animated toy "monsters". Mother-reared but not surrogate-peer-reared subjects, however, also manifested elevated cortisol levels when an animal in an adjacent cage was captured and removed for stress testing. Mother-reared infant monkeys thus responded in a stronger and more prolonged manner to the loss of their attachment object than surrogate-peer-reared infants. These results suggest that infant rhesus monkeys form stronger attachments to monkey mothers than to inanimate surrogate mothers, a phenomenon which has not been as clearly demonstrated using other indices of attachment strength.

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    • "One major limitation to these early studies is the severity of separation from conspecifics; most humans are not exposed to such extreme deprivation of social contact so early in life. Thus, in the past few decades, experimental rearing conditions have evolved to include more social contact in the form of peer-only rearing (PR), in which monkeys are reared for the first 6 to 12 months of life for up to 24 hours/day with same-aged peers but no adults (Capitanio et al. 2005; Dettmer et al. 2012; Shannon et al. 1998); surrogate-peer-rearing (SPR), in which monkeys are reared alone in single cages for the majority of the day but are provided with up to 2 hours of daily play sessions with agemates (Dettmer et al. 2012; Sackett et al. 2002; Shannon et al. 1998); and repeated brief separations from mothers or social partners versus total separation (Barr, Newman, Shannon et al. 2004; Hennessey 1997; Hoffman et al. 1995; Levine and Mody 2003; Mendoza and Mason 1997; Meyer et al. 1975; Rilling et al. 2001). Even with these less-severe separation paradigms, studies have consistently shown that young monkeys exposed to disruptions in the mother-infant bond or to adverse early rearing exhibit greater behavioral and physiological responsivity to separation; distress vocalizations, freezing behavior, and aggressive behaviors (e.g., cage-biting and cage-shaking) are increased in noncontrol monkeys, whereas object exploration and social contact upon reunion are decreased. "
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    ABSTRACT: This report reviews the scientific literature from the past several decades that focuses on nonhuman primates (NHPs) as models of neuropsychiatric disorders, including anxiety, and alcoholism. In particular, we highlight the approaches, advantages, and disadvantages of the rearing, genetic, and epigenetic methodologies behind these studies as a means of evaluating the application of these methods in assessing disorders in NHPs as models of human disease. Finally, we describe the contributions the NHP studies have made to neuropsychiatric research and areas for future research.
    ILAR journal / National Research Council, Institute of Laboratory Animal Resources 09/2014; 55(2):361-70. DOI:10.1093/ilar/ilu025 · 2.39 Impact Factor
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    • "In non-human primates, while results are not entirely consistent (Dettmer et al., 2012), early social deprivation appears to down-rather than up-regulate the HPA axis (Meyer et al., 1975; Clarke, 1993; Cirulli et al., 2009). This was confirmed recently in a large study of Rhesus macaques (Hawkley et al., 2012). "
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    ABSTRACT: Growing evidence suggests that early social deprivation impacts the activity of the hypothalamic-pituitary-adrenocortical axis. Early adverse care in the form of institutional or orphanage care provides a human model for early social deprivation. The present study examined changes in diurnal cortisol during the transition to family care in the first 2 years post-adoption. Children adopted between 15 and 36 months from institutional care were examined four times during their first 2 years post-adoption (N=58). Comparison groups included same-aged peers reared in their birth families (N=50) and children adopted during their first year from overseas foster care (N=47). Children provided daily cortisol samples at roughly 2, 9, 17, and 25 months post-adoption. Post-institutionalized and post-foster care children exhibited less steep diurnal cortisol compared to non-adopted same-aged peers; these differences did not diminish across the 2 year period. For post-institutionalized children, lower social care quality in institutions was associated with less steep cortisol slopes. Lastly, shallower diurnal cortisol was a mediator between adoption status and increased behavioral problems 2 years post-adoption. Consistent with the non-human primate literature, early social deprivation may contribute to early programming of the HPA axis.
    Psychoneuroendocrinology 08/2014; 50C:1-13. DOI:10.1016/j.psyneuen.2014.07.028 · 4.94 Impact Factor
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    • ") under various circumstances . In one study in which MR , PR , and SPR infants were compared , both nursery reared groups ( PR and SPR ) exhibited lower basal levels of plasma corti - sol when compared to MR infants ( Shannon et al . , 1998 ) . SPR infants also showed a reduced response to the stress of a brief separation compared to MR infants ( Meyer et al . , 1975 ; Shannon et al . , 1998 ) . Similarly , juvenile ( 1 – 3 years old ) SPR infants exhibited lower salivary cortisol levels than MR juveniles after capture and sedation for a health exam ( Davenport et al . , 2003 ) . One of the limitations of the above work and a possible contributor to the variability of findings is the reliance on pla"
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    Applied Animal Behaviour Science 01/2013; 143(2-4):135-149. DOI:10.1016/j.applanim.2012.10.012 · 1.69 Impact Factor
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