“Neurobiology of Affiliative Behavior in Nonhuman Primates”

Horst D. Steklis and Arthur Kling


found in The Psychobiology of Attachment and Separation, edited by Martin Reite and Tiffany Field

Academic Press, Inc, 1985 – Orlando

ISBN 0125867808

Pp 93-134


“Positive or affiliative social interactions (those behaviors that promote the development of and that serve to maintain social bonds within primate society)….  (Steklis/na/94)”

“Very little will be said about the neural bases of these behaviors in humans, because sufficient comparable quantitative data are not yet available.  (Steklis/na/94)”

“…peer separation is followed by affective reactions similar to those following mother-infant separation (e.g. Bowden & McKinney, 1972).  Play is the predominant form of social interaction among peers, and the social roles and relationships (e.g. dominance rank) that are assumed in adulthood first emerge in this context (Dolhinow & Bishop, 1970).  (Steklis/na/95)”

“Several observations have been made on amygdala-lesioned fe- (Steklis/na/95)males (Macaca mulatta) in laboratory ages.  In all cases, the mothers neglected and abused the infants by pushing them off their bodies and forcing them to remain on the floor, and some were observed to toss the infants about as though they were foreign objects.  Biting and chewing of the infants was also observed in several cases.  (Steklis/na/96)”

“…lesions of anterior temporal cortex…neglected their infants….  These mothers failed to retrieve their infants in threatening situations and generally ignored them.  They did, however, allow the infant to be near and to nurse.  (Steklis/na/96)”

“Additional observations made by Franzen and Myers (1973a) on mothers who sustained anterior temporal lesions revealed that, in addition to being neglectful, mothers also directed unusual amounts of physical aggression toward their infants.  (Steklis/na/97)”


this info from his table (Steklis/na/96)

++ lesion to amygdala, mother abused or killed neonates

++ lesion to anterior temporal cortex, loss of protective retrieval and ignoring of infants; physical abuse

++ prefrontal lobectomy, neglect and physical abuse of infants

++ lesion to cingulate cortex, normal maternal behavior

++ lesion to visual association cortex, normal maternal behavior


“In adult subjects of all species studied, the influence of frontal-temporal lesions on affiliative behavior is clearly toward decreased affiliative behavior in the laboratory and social isolation in semi- or free-ranging settings…  (Steklis/na/113)”

“…bilateral damage to the amygdaloid nuclei, temporal polar cortex, or orbital cortex results in the most marked deficits in affiliative behavior in a wide range of nonhuman primate species.  There is evidence that in some instances lesions confined to dorsolateral prefrontal cortex may also produce quantitative decrements in measures of affiliative behavior, although to a lesser degree than following ablations including orbital cortex.  Singh (1976) compared the social-behavioral effects of dorsolateral frontal cortex removal or prefrontal lobectomy (dorsolateral and orbital cortex) in a confined group of M. mulatta.  Compared to unoperated control subjects, subjects in both lesion groups engaged in significantly fewer grooming interactions.  Only the lobectomized animals, however, avoided positive social interactions with all nonlobectomized monkeys.  On the basis of these interaction patterns, two separate groups appeared to exist, one consisting of unoperated and dorsolateral-lesioned monkeys and the other of the lobectomized monkeys.  This result is highly similar to the social segregation between operates and normals reported for orbital-lesioned C. aethiops (Raleigh, 1977) and amygdalectomized M. arctoides (Kling & Dunne, 1976), suggesting that damage to orbital cortex and not lesion size per se (i.e. combined orbital and dorsolateral cortex) produced this extreme form of social withdrawal by lobectomized subjects in the Singh (1976) study.  (Steklis/na/113)”

“It is also apparent from the studies…that the behavioral outcome of lesions to these neural areas will vary according to the environmental setting in which the subject is evaluated.  For example, when housed in small laboratory cages or enclosures, as dyads or small social groups, lesioned monkeys may show fear of normal cage mates and be subordinate to them, but they may not differ from their normal cage mates in frequencies of social exploration (i.e. grooming, clasping, touching) or social play (Thompson & Towfighi, 1976).  In large enclosures or free-ranging settings, where adequate spatial separation becomes possible, subjects with similar lesions tend to separate from normal group members, form a subgroup, or become social isolates.  (Steklis/na/113)”

I’m not sure what function these parts of the brain they are talking about have, but I wonder for those of us whose brains didn’t develop right, given enough space and a “different” world if we wouldn’t find each other in this same wa.


“…mesolimbic dopaminergic system and schizophrenia…  (Steklis/na/119)”

“Among the highest dopamine concentrations in cerebral cortex are found in orbital-frontal and anterior temporal cortex (Brown, Crane, & Goldman, 1979), and the latter also contains high concentrations of noradrenaline and serotonin….  Serotonin and dopamine appear to be found in high concentrations in those cortical and subcortical areas related so social-affiliative behavior.  (Steklis/na/119)”

“…low levels of brain dopaminergic activity are related to general social initiative, whereas high levels contribute to social withdrawal….further studies are needed to examine the relationship between peripheral and brain MAO activity on the one hand and the relationship between brain dopaminergic activity and social-affiliative behaviors on the other.  (Steklis/na/123)”



“The amygdala, especially the central and medial nuclei, stands out as an area particularly rich in concentrations of cells, terminals, and receptors associated with various peptides….  Many of these peptides are found in both gut and brain, but their specific functional contribution to brain and behavior is still unknown.  (Steklis/na/124”  (1985)

“The amygdala also contains receptors for the steroid hormones cortisol, dihydrotestosterone, and estradiol (Stumpf & Sar, 1978), suggesting a role in neuroendocrine mechanisms and sexually differentiated behavioral function….  (Steklis/na/124)”

“Particularly exciting has been the discovery of several opiate-like peptides, or endorphins, in brain tissue, which have been linked to a wide variety of behavioral functions…  (Steklis/na/124)”

“The role of endorphins in social-affiliative behavior among primates is at present relatively unexplored.  The few existing studies, however, do suggest that endorphins contribute to the formation and maintenance of social attachments in mammals.  (Steklis/na/125)”

“…one of the major behavioral functions of the amygdala is to respond selectively to sensory stimuli on the basis of their significance to the animal.  It bears repeating that some amygdala cells selectively respond to complex social stimuli (e.g., monkey faces), which may form part of a specialized neural system for the processing of social stimuli.  (Steklis/na/129)”


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