Washington State recreational marijuana legalization: parent and adolescent perceptions, knowledge, and discussions in a sample of low-income families

BACKGROUND

In November 2012, Washington State and Colorado became the first states in the United States to legalize recreational marijuana use for adults, and Uruguay became the first country to allow the cultivation, distribution, possession, and use of marijuana. One possible consequence of these changes is increased adolescent marijuana use. Parents may mitigate this adverse consequence; however, whether parents and adolescents have accurate knowledge about the laws and are discussing marijuana use in light of the law changes is unknown.

OBJECTIVE

We examine perceptions, knowledge, and parent-child discussions about Washington State's recreational marijuana law in a sample of low-income families.

METHODS

Participants were a subset of families (n = 115) in an ongoing study that originally recruited parents and adolescents from middle schools in Tacoma, Washington. In summer 2013, when students were entering the 11(th) grade, students and their parents were asked questions about the recreational marijuana law.

RESULTS

Participants perceived that their marijuana-related attitudes and behaviors changed little as a result of the law, and displayed uncertainty about what is legal and illegal. Most parents reported discussing the new law with their children but only occasionally, and conversations emphasized household rules, particularly among parent lifetime marijuana users compared to non-users. Conclusions/Importance: Results suggest that there should be a public health campaign focused on families that provides clear information about the recreational marijuana laws.

Neonatal amygdala lesions alter responsiveness to objects in juvenile macaques

The amygdala is widely recognized to play a central role in emotional processing. In nonhuman primates, the amygdala appears to be critical for generating appropriate behavioral responses in emotionally salient contexts. One common finding is that macaque monkeys that receive amygdala lesions as adults are behaviorally uninhibited in the presence of potentially dangerous objects. While control animals avoid these objects, amygdala-lesioned animals readily interact with them. Despite a large literature documenting the role of the amygdala in emotional processing in adult rhesus macaques, little research has assessed the role of the amygdala across the macaque neurodevelopmental trajectory. We assessed the behavioral responses of 3-year-old (juvenile) rhesus macaques that received bilateral ibotenic acid lesions of the amygdala or hippocampus at 2 weeks of age. Animals were presented with salient objects known to produce robust fear-related responses in macaques (e.g., snakes and reptile-like objects), mammal-like objects that included animal-like features (e.g., eyes and mouths) but not reptile-like features (e.g., scales), and non-animal objects. The visual complexity of objects was scaled to vary the objects' salience. In contrast to control and hippocampus-lesioned animals, amygdala-lesioned animals were uninhibited in the presence of potentially dangerous objects. They readily retrieved food rewards placed near these objects and physically explored the objects. Furthermore, while control and hippocampus-lesioned animals differentiated between levels of object complexity, amygdala-lesioned animals did not. Taken together, these findings suggest that early damage to the amygdala, like damage sustained during adulthood, permanently compromises emotional processing.

Intranasal vasopressin affects pair bonding and peripheral gene expression in male Callicebus cupreus

Arginine vasopressin (AVP) is a neuropeptide hormone and neurotransmitter that has peripheral functions in water regulation, and central functions in the stress response and social bonding in male rodents. In this study, we investigated the role of AVP in partner preference behavior in a monogamous primate, the coppery titi monkey (Callicebus cupreus). Seven titi males each received three intranasal treatments: saline, low AVP (40 IU) and high AVP (80 IU) in random order, 1 week apart. They experienced a series of stimulus exposures to their female partner, a female stranger and an empty cage. Males were more likely to contact the stimulus and do so faster when either female stimulus was present. When pretreated with saline, males contacted the stranger more frequently than their partner; when pretreated with the high dosage of AVP, males contacted their partner more frequently than the stranger. We used microarray to measure peripheral changes in gene expression associated with intranasal AVP and found reduced expression of several genes coding for proinflammatory cytokines. The data presented here suggest that intranasally administered AVP has both central influences on social behavior and peripheral influences on inflammation in a nonhuman primate.

Interest in infants by female rhesus monkeys with neonatal lesions of the amygdala or hippocampus

Previous research in our laboratory has shown that damage to the amygdala in neonatal rhesus monkeys profoundly alters behaviors associated with fear processing, while leaving many aspects of social development intact. Little is known, however, about the impact of neonatal lesions of the amygdala on later developing aspects of social behavior. A well-defined phenomenon in the development of young female rhesus monkeys is an intense interest in infants that is typically characterized by initiating proximity or attempting to hold them. The extent to which young females are interested in infants may have important consequences for the development of species-typical maternal behavior. Here we report the results of a study that was designed to assess interest in infants by female rhesus monkeys that received neonatal lesions to the amygdala, hippocampus or a sham surgical procedure. Subjects were first paired with pregnant "stimulus" females to assess social interactions with them prior to the birth of the infants. There were few behavioral differences between lesion groups when interacting with the pregnant females. However, following the birth of the infants, the amygdala-lesioned females showed significantly less interest in the infants than did control or hippocampus-lesioned females. They directed fewer affiliative vocalizations and facial expressions to the mother-infant pair compared to the hippocampus-lesioned and control females. These findings suggest that neonatal damage to the amygdala, but not the hippocampus, impairs important precursors of non-human primate maternal behavior.

Serotonin transporter expression is predicted by early life stress and is associated with disinhibited behavior in infant rhesus macaques

Serotonin transporter (5-HTT) expression patterns may contribute to the risk for adverse psychological outcomes following early life stress. The present study investigated whether two types of early life stress, maternal and social aggression, and a serotonin transporter gene promoter polymorphism (rh5-HTTLPR) predicted lower post-stressor peripheral blood mononuclear cell (PBMC) 5-HTT expression in infant rhesus macaques. We further probed the relationships among these factors and infant behavioral disinhibition within a stressful situation. Fifty-three infants residing with mothers in large, complex social groups were observed over the first 12 postnatal weeks, during which time the rate of aggression received by the infant from their mothers and social group members was recorded. At 90-120 days of age, infants underwent a 25-h maternal separation/biobehavioral assessment, which included standardized behavioral assessments and blood sampling. Infants' rh5-HTTLPR genotypes were determined, and infant 5-HTT expression was quantified from PBMCs collected 8 h after separation. Receipt of aggression from the mother, but not from social group members, was associated with lower post-stressor 5-HTT expression. Lower post-stressor 5-HTT expression, but not receipt of aggression, was associated with disinhibited behavior during assessment. Rh5-HTTLPR genotype was unrelated to any measure. We conclude that 5-HTT regulation is linked with specific, presumably stressful early experiences in infant rhesus macaques. Further, 5-HTT expression predicted behavioral disinhibition, presumably via parallel processes that operate in the brain.

Emergence of stereotypies in juvenile monkeys (Macaca mulatta) with neonatal amygdala or hippocampus lesions

The emergence of stereotypies was examined in juvenile rhesus monkeys (Macaca mulatta) who, at 2 weeks of postnatal age, received selective bilateral ibotenic acid lesions of the amygdala (N = 8) or hippocampus (N = 8). The lesion groups were compared to age-matched control subjects that received a sham surgical procedure (N = 8). All subjects were maternally reared for the first 6 months and provided access to social groups throughout development. Pronounced stereotypies were not observed in any of the experimental groups during the first year of life. However, between 1 to 2 years of age, both amygdala- and hippocampus-lesioned subjects began to exhibit stereotypies. When observed as juveniles, both amygdala- and hippocampus-lesioned subjects consistently produced more stereotypies than the control subjects in a variety of contexts. More interesting, neonatal lesions of either the amygdala or hippocampus resulted in unique repertoires of repetitive behaviors. Amygdala-lesioned subjects exhibited more self-directed stereotypies and the hippocampus-lesioned subjects displayed more head-twisting. We discuss these results in relation to the neurobiological basis of repetitive stereotypies in neurodevelopmental disorders, such as autism.

Dimensions of response to novelty are associated with social engagement and aggression in adult male rhesus macaques (Macaca mulatta)

In this study, the authors tested the hypothesis that behavioral response across social and nonsocial, novel and familiar conditions may be guided by the same trait(s) related to impulsivity in adult male rhesus macaques. The authors assessed 23 individuals' behavioral response to a series of nonsocial novel scenarios, as well as aggression and sociality within familiar and novel social contexts. Factor analysis of responses to nonsocial novelty identified two factors: Caution, which reflected latency to engage different novel situations, and Interest in Novelty, which consisted of duration and quality of exploration. Each dimension was associated with different social manifestations. Caution was negatively correlated with social aggression in novel and familiar social circumstances; Interest in Novelty was positively associated with social engagement in familiar, but not novel, social circumstances. The authors conclude that traits influencing impulsive response to novelty contribute to risky and normal social behavior across social contexts.

The expression of social dominance following neonatal lesions of the amygdala or hippocampus in rhesus monkeys (Macaca mulatta)

As part of ongoing studies on the neurobiology of socioemotional behavior in the nonhuman primate, the authors examined the social dominance hierarchy of juvenile macaque monkeys (Macaca mulatta) that received bilateral ibotenic acid lesions of the amygdala or the hippocampus or a sham surgical procedure at 2 weeks of age. The subjects were reared by their mothers with daily access to large social groups. Behavioral observations were conducted while monkeys were given access to a limited preferred food. This testing situation reliably elicited numerous species-typical dominance behaviors. All subjects were motivated to retrieve the food when tested individually. However, when a group of 6 monkeys was given access to only 1 container of the preferred food, the amygdala-lesioned monkeys had less frequent initial access to the food, had longer latencies to obtain the food, and demonstrated fewer species-typical aggressive behaviors. They were thus lower ranking on all indices of social dominance. The authors discuss these findings in relation to the role of the amygdala in the establishment of social rank and the regulation of aggression and fear.

The development of social behavior following neonatal amygdala lesions in rhesus monkeys

We examined the role of the amygdala in the development of nonhuman primate social behavior. Twenty-four rhesus monkeys received bilateral ibotenic acid lesions of either the amygdala or the hippocampus or received a sham surgical procedure at 2 weeks of age. Subjects were reared with their mothers and were provided daily access to social rearing cohorts. The subjects were weaned at 6 months of age and then observed while paired with familiar conspecifics at 6 and 9 months of age and with unfamiliar conspecifics at 1 year of age. The subjects were also observed during daily cohort socialization periods. Neither amygdala nor hippocampus lesions altered fundamental aspects of social behavior development. All subjects, regardless of lesion condition, developed a species-typical repertoire of social behavior and displayed interest in conspecifics during social encounters. The amygdala lesions, however, clearly affected behaviors related to fear processing. The amygdala-lesioned subjects produced more fear behaviors during social encounters than did control or hippocampus-lesioned subjects. Although the heightened fear response of the amygdala-lesioned subjects was consistent across different testing paradigms and was observed with both familiar and novel partners, it did not preclude social interactions. In fact, the amygdala-lesioned subjects displayed particular social behaviors, such as following, cooing, grunting, presenting to be groomed, and presenting to be mounted more frequently than either control or hippocampus-lesioned subjects. These findings are consistent with the view that the amygdala is not needed to develop fundamental aspects of social behavior and may be more related to the detection and avoidance of environmental dangers.

Behavioral and physiological adaptation to repeated chair restraint in rhesus macaques

Physical restraint is a commonly used procedure when working closely with nonhuman primates. Nonhuman primates show rapid behavioral changes when learning the restraint procedure, and these changes have been taken to reflect behavioral and physiological habituation to the procedure. This study examined the behavioral and adrenocortical responses to repeated physical restraint in a large sample of adult male rhesus monkeys. Subjects showed a decline in behavioral agitation and cortisol concentrations across seven consecutive days of restraint. The changes in adrenocortical responsiveness were also coincident with an increased sensitivity to dexamethasone and a change in early morning basal cortisol secretion. The subjects were restrained for a single session 6 months later, and while the reduction in behavioral agitation was still present, the majority of changes in adrenocortical responsiveness were no longer present. These data show that behavior is not necessarily an indicator of underlying physiological processes and that the reduction of hypothalamic-pituitary-adrenal (HPA) activity with repeated restraint is due to physiological adaptation to high glucocorticoid concentrations and not to psychological habituation to the restraint procedures.

The development of mother-infant interactions after neonatal amygdala lesions in rhesus monkeys

As part of ongoing studies on the neurobiology of socioemotional behavior in the nonhuman primate, we examined the development of mother-infant interactions in 24 macaque monkeys who received either bilateral amygdala or hippocampus ibotenic acid lesions, or a sham surgical procedure at 2 weeks of age. After surgery, the infants were returned to their mothers and reared with daily access to small social groups. Behavioral observations of the infants in dyads (mother-infant pairs alone), tetrads (two mother-infant pairs), and social groups (six mother-infant pairs and one adult male) revealed species-typical mother-infant interactions for all lesion conditions, with the exception of increased physical contact time between the amygdala-lesioned infants and their mothers. Immediately after permanent separation from their mothers at 6 months of age, the infants were tested in a mother preference test that allowed the infants to choose between their mother and another familiar adult female. Unlike control and hippocampus-lesioned infants, the amygdala-lesioned infants did not preferentially seek proximity to their mother, nor did they produce distress vocalizations. Given the normal development of mother-infant interactions observed before weaning, we attribute the behavior of the amygdala-lesioned infants during the preference test to an impaired ability to perceive potential danger (i.e., separation from their mother in a novel environment), rather than to a disruption of the mother-infant relationship. These results are consistent with the view that the amygdala is not essential for fundamental aspects of social behavior but is necessary to evaluate potentially dangerous situations and to coordinate appropriate behavioral responses.

Developmental changes in responsiveness to parents and unfamiliar adults in a monogamous monkey (Callicebus moloch)

Titi monkeys (Callicebus moloch) are monogamous New World primates that are characteristically found in family-type groups consisting of a mated adult pair and one or two young. The factors maintaining the small size of these groups are not known. Based on observations of free-ranging and captive families, parental aggression toward older offspring seems unlikely to play a significant role. Maturing individuals themselves, however, could undergo behavioral changes that weaken ties to their natal group. These might include waning of affiliative relations with parents, or subtle forms of aversion. Independent of such changes, increasing interest in unfamiliar conspecifics could be a factor. We examined these possibilities in the present study by assessing changes in social behavior and social preferences from initial ambulatory independence (6 months) through reproductive maturity (24 months) in a combined cross-sectional/longitudinal study of 21 captive titi monkeys living with their parents. Responses to both parents and to an unfamiliar adult heterosexual pair, a single unfamiliar adult male, and a single unfamiliar adult female were observed when subjects were given a choice between parents and strangers presented simultaneously or as the only social incentive. Social stimuli were at opposite ends of a 16.8-m-long test corridor. Subjects could move freely about the corridor for 5 min with each configuration of social stimuli. They stayed closer to parents than to strangers at all ages. Responsiveness to strangers increased with age and suggested growing ambivalence, particularly toward the male stranger. As they approached 24 months of age, male subjects showed a dramatic increase in the frequency and intensity of agonistic behaviors toward male strangers, behaviors that were rarely directed toward female strangers or parents. Waning of attraction to parents may be less important in dispersal from the natal group than changing reactions to strangers.

Increased social fear and decreased fear of objects in monkeys with neonatal amygdala lesions

The amygdala has been implicated in the mediation of emotional and species-specific social behavior (Kling et al., 1970; Kling and Brothers, 1992; Kluver and Bucy, 1939; Rosvold et al., 1954). Humans with bilateral amygdala damage are impaired in judging negative emotion in facial expressions and making accurate judgements of trustworthiness (Adolphs et al., 1998, 1994). Amygdala dysfunction has also been implicated in human disorders ranging from social anxiety (Birbaumer et al., 1998) to depression (Drevets, 2000) to autism (Bachevalier, 1994; Baron-Cohen et al., 2000; Bauman and Kemper, 1993). We produced selective amygdala lesions in 2-week-old macaque monkeys who were returned to their mothers for rearing. At 6-8 months of age, the lesioned animals demonstrated less fear of novel objects such as rubber snakes than age-matched controls. However, they displayed substantially more fear behavior than controls during dyadic social interactions. These results suggest that neonatal amygdala lesions dissociate a system that mediates social fear from one that mediates fear of inanimate objects. Furthermore, much of the age-appropriate repertoire of social behavior was present in amygdala-lesioned infants indicating that these lesions do not produce autistic-like behavior in monkeys. Finally, amygdala lesions early in development have different effects on social behavior than lesions produced in adulthood.

The effects of bilateral lesions of the amygdala on dyadic social interactions in rhesus monkeys (Macaca mulatta)

The role of the amygdala in dyadic social interactions of adult rhesus monkeys (Macaca mulatta) was assessed after bilateral ibotenic acid lesions. Social, nonsocial, and spatial behaviors of amygdalectomized and control monkeys were assessed in 3 dyadic experiments: constrained, unconstrained, and round robin. Lesions produced extensive bilateral damage to the amygdala. Across all experiments, the amygdalectomized monkeys demonstrated increased social affiliation, decreased anxiety, and increased confidence compared with control monkeys, particularly during early encounters. Normal subjects also demonstrated increased social affiliation toward the amygdalectomized subjects. These results indicate that amygdala lesions in adult monkeys lead to a decrease in the species-normal reluctance to immediately engage a novel conspecific in social behavior. The altered behavior of the amygdalectomized monkeys may have induced the increased social interactions from their normal companions. This is contrary to the idea that amygdalectomy produces a decrease in social interaction and increased aggression from conspecifics.

Family, religious, school and peer influences on adolescent alcohol use: a longitudinal study

OBJECTIVE

In this study, the cross-temporal relationship between family social support and adolescent alcohol use was examined. A primary aim was to investigate the mechanisms through which family social support affects drinking among youth. Another aim was to examine reciprocal relationships among the study variables.

METHOD

Four-wave (with 6-month intervals) panel survey data collected from 840 middle adolescent boys (n = 443) and girls (n = 397) attending a suburban school district in western New York were analyzed using structural equation modeling with maximum likelihood estimation.

RESULTS

Analyses revealed that family social support was indirectly associated with decreased alcohol consumption among the respondents, primarily through variables measuring religiosity, school grades and peer alcohol use. In addition, adolescent alcohol use was directly associated with subsequent increases in peer alcohol use and later decreases in school performance. Results also showed that receiving good grades in school predicted moderate increases in family social support.

CONCLUSIONS

The findings of this study are discussed in terms of the interrelationships that exist among multiple socializing influences and alcohol use among adolescents.

Annual physiological changes in individually housed squirrel monkeys (Saimiri sciureus)

This study investigated whether annual changes in physiology occur in individually housed squirrel monkeys (Saimiri sciureus). Physiological measures were monitored for 20 months. Over the course of the study, all individually housed males and females exhibited clear annual changes in gonadal and adrenal hormone levels, and males exhibited species-typical changes in body weight. Females exhibited a typical pattern of hormonal changes, with elevations in gonadal steroids occurring during the same months as elevations in cortisol. Males, however, exhibited an atypical pattern, as elevations in hormone levels were not synchronized with each other; rather, elevations in testosterone occurred out of phase with changes in cortisol and body weight. The timing of annual events in individually housed subjects was compared to that in nearby social groups, in which the timing of the breeding season from year to year was determined by social group formations and was outside the naturally occurring breeding season. Elevations of ovarian and adrenocortical hormones in individually housed females were synchronized with indices of breeding in heterosexual social groups. Similarly, weight gain in males was associated with elevations in cortisol and, as with socially housed males, tended to precede seasonal breeding in the social groups. In contrast, annual testosterone elevations for individually housed males were not synchronized with breeding in nearby social groups. We conclude that direct physical interaction is not required for the annual expression of breeding readiness. Synchrony of seasonality among squirrel monkeys may be accomplished by distant social cues in females, but males may require physical interaction for complete synchrony of annual physiological changes.

Reproductive biology of female titi monkeys (Callicebus moloch) in captivity

Titi monkeys (Callicebus spp., Cebidae) are monogamous neotropical primates that live in family-like groups typically consisting of an adult monogamous pair and one or two young. Knowledge about the reproductive biology of this genus is scanty. This study investigated the reproductive biology of female dusky titi monkeys (Callicebus moloch). An initial analysis characterized reproductive parameters of 32 females from a captive colony maintained for 23 years at the California Regional Primate Research Center (CRPRC). The colony records provided data on reproductive parameters such as interbirth intervals, seasonality, age at first pregnancy, and reproductive rate in captivity. Changes in urinary levels of estrone conjugates (E1C) and pregnanediol-3alpha-glucuronide (PdG) were used to characterize major reproductive events. Urine samples from eleven females were collected during 17 months. The endocrine data were used to examine changes associated with cycling, conception, and the post-partum period as well as to determine the duration of the ovarian cycle and gestation length. The analysis of colony records indicated that females whose infant survived through weaning gave birth at intervals remarkably close to one year, while those who lost their offspring showed a significantly shorter interval. As long as they lived within the family group, mature female offspring did not breed. The analysis of the endocrine profiles indicated that after giving birth to a viable offspring, females undergo a relatively prolonged period of anovulation (approx. 6.5 months), followed by 1-3 non-conceptive cycles (approx. 1 month), after which they conceive and gestate (4.3 months).

Effects of duration of separation on responses to mates and strangers in the monogamous titi monkey (Callicebus moloch)

Adult male and female titi monkeys form an intense social bond characterized by high levels of affiliative interactions between pairmates and agonistic responses to strangers. In natural settings, separation between mates can vary from brief periods, as when mates drift apart during feeding, to permanent separation, occasioned by desertion or death. In this study we asked how different durations of separation altered the behavior of male and female titi monkeys (Callicebus moloch). We compared the effects of brief separation such as might occur incidentally during feeding (1-2 h) with prolonged separation such as might occur if one partner died or deserted (5 days). Effects were observed during a 30 min reunion of pairmates or during a 30 min encounter with a stranger of the opposite sex. Following brief separation, interactions between mates and between strangers clearly differed in measures of affiliation, but not in behaviors indicative of arousal. Following prolonged separation, measures of arousal increased with both mated pairs and strangers. Females tended to interact more readily with a stranger following prolonged separation than after brief separation, but interactions between mates were essentially unchanged and differed substantially from those between strangers. The data suggest that the pair bond persists in titi monkeys after prolonged social isolation, despite increased interest in interacting with potential new partners.

Cognitive style: problem solving by rhesus macaques (Macaca mulatta) reared with living or inanimate substitute mothers

Cognitive style, reflected in the generation of novel solutions and the use of identifiable response strategies in problem-solving situations, was contrasted in rhesus monkeys (Macaca mulatta) reared individually with either canine companions or inanimate surrogate mothers. Four experiments were conducted over a 5-year period, examining problem solving in relatively unstructured as well as more formal situations. Results indicated that whereas the 2 rearing groups did not differ on most measures of performance, consistent response strategies were identified for the dog-raised monkeys. The results were compared with previously published data from the same monkeys demonstrating rearing group differences in abilities to engage in complex social interaction. The animate nature of the early rearing environment may facilitate-the development of a cognitive style that influences problem-solving abilities in both the social and nonsocial realms.

Generic aspects of primate attachments: parents, offspring and mates

We examine behavioral and physiological aspects of primate emotional attachments in the context of four relationships: infant-to-parent, parent-to-infant, and adult male-to-female and adult female-to-male in a monogamous New World species. Emotional attachments in each of these relationships show striking similarities at a basic functional level. The nature of these similarities suggests that they are produced by the same psychoneuroendocrine core, which appears to be present in all mammals. We also consider the development of each of kind of attachment. In contrast to fundamental similarities in the expression of attachment, their development in each case appears to be based on distinct, species-typical dispositions and constraints.

Sexual and physical abuse among incarcerated youth: implications for sexual behavior, contraceptive use, and teenage pregnancy

OBJECTIVE

In the present study, physical and sexual abuse among incarcerated youth were examined with respect to sexual activity, contraceptive use, and pregnancy.

METHOD

The self-report survey data were collected from 62 females and 334 males who were incarcerated in Nevada youth correctional facilities in the summer of 1994. Of the males, 46.8% (n = 156) reported a history of physical abuse and 9.9% (n = 33) reported sexual abuse. A surprisingly high 73% (n = 46) of the females reported a history of physical abuse and 68.3% (n = 43) reported sexual abuse.

RESULTS

The analyses indicated that females who reported a history of sexual abuse had an earlier mean age of first intercourse than those who reported no sexual abuse. In addition, male and female respondents with a history of physical and/or sexual abuse reported using no method of contraception as compared to youth with no history of abuse.

CONCLUSIONS

Implications of these results for detention-based counseling and prevention programming are discussed.

Words, deeds, and motivations: comment on Maestripieri and Carroll (1998)

A considerable proportion of Old World monkey mothers living in social groups under seemingly benign conditions maltreat their young. This interesting finding is the basis for the suggestion by D. Maestripieri and K. A. Carroll (1998) that monkeys might provide an animal model for investigating child abuse and neglect in the human population. This suggestion tacitly assumes that the phenomena of abuse and neglect in monkeys and humans are based on similar processes. This possibility is more plausible for neglect than for abuse. Child abuse shows such great diversity of forms and causes in human societies that it is unlikely to have a natural counterpart among nonhuman primates. The suggestion that it does may inadvertently lend support to attitudes that are unduly restrictive or actively opposed to animal research in psychology.

Social stress results in altered glucocorticoid regulation and shorter survival in simian acquired immune deficiency syndrome

From early in the AIDS epidemic, psychosocial stressors have been proposed as contributors to the variation in disease course. To test this hypothesis, rhesus macaques were assigned to stable or unstable social conditions and were inoculated with the simian immunodeficiency virus. Animals in the unstable condition displayed more agonism and less affiliation, shorter survival, and lower basal concentrations of plasma cortisol compared with stable animals. Early after inoculation, but before the emergence of group differences in cortisol levels, animals receiving social threats had higher concentrations of simian immunodeficiency virus RNA in plasma, and those engaging in affiliation had lower concentrations. The results indicate that social factors can have a significant impact on the course of immunodeficiency disease. Socially induced changes in pituitary-adrenal hormones may be one mechanism mediating this relationship.

Autonomic balance in Saimiri sciureus and Callicebus moloch: relation to life-style

Previous research has shown heart rate to be substantially higher in squirrel monkeys (Saimiri sciureus) than titi monkeys (Callicebus moloch). In order to evaluate whether species differences in heart rate can be accounted for by contrasting patterns of autonomic activity, heart rate in response to novel test conditions was compared using standard pharmacological agents that selectively block the sympathetic (propranolol) or parasympathetic (atropine) components of the autonomic nervous system. Squirrel monkeys were found to exhibit greater sympathetic response to novelty than titi monkeys. In contrast, sympathetic activity in titi monkeys, but not squirrel monkeys, was quickly counteracted by a strong parasympathetic response. Intrinsic heart rates, estimated by blocking both parasympathetic and sympathetic input to the heart, were within the ranges of values predicted by body weight. Heart rate for titi monkeys stabilizes at intrinsic heart rate, whereas heart rate for squirrel monkeys is maintained well above intrinsic heart rate in a novel environment. The contrast between species in autonomic balance is consistent with and probably contributes to each species characteristic mode of interacting with their social and non-social environment.