Twins and friendship.

A growing body of literature asserts the importance of friendships for a child's emotional wellbeing, behavioural adjustment and developmental attainment. However, few studies have examined friendships in the twin situation. This paper examines the literature on friendships among children who are twins and asks two questions: (1) What are the implications of the twin situation for friendship formation? (2) How can the twin situation inform theoretical knowledge concerning friendship formation in the general population? The discussion examines the implications of the twin situation for the size and nature of twin children's friendship pool and questions whether children who are twins are more likely to be adaptive or maladaptive in their social behaviour. The paper argues for the need to study the process and mechanisms in friendship formation among twin children because the findings might inform not only studies of friendship but also behavioural genetic research.     

Addiction: pulling at the neural threads of social behaviors

Addiction coopts the brain's neuronal circuits necessary for insight, reward, motivation, and social behaviors. This functional overlap results in addicted individuals making poor choices despite awareness of the negative consequences; it explains why previously rewarding life situations and the threat of judicial punishment cannot stop drug taking and why a medical rather than a criminal approach is more effective in curtailing addiction.     

Wild chimpanzees can perform social grooming and social play behaviors simultaneously

Reliable evidence was obtained of the simultaneous performance of social grooming and social play behaviors by individuals among wild chimpanzees of the M group in Mahale Mountains National Park. I observed three cases of this performance: in an old female, a young female, and an adult male. While the agent was grooming the back of an adult bimanually, an infant or a juvenile approached the agent. The agent then started playing with the infant/juvenile using only the right hand, while simultaneously grooming the back of the adult with the left hand. In one case, an old female continued the simultaneous performance for about 1 min. Such performances probably occur at low frequency because they are not often required. The similarity in the neurobiological bases and the functions of social grooming and social play behaviors, both of which include repetitive contact with the body of another individual, may facilitate their simultaneous performance.     

German Observational Study of Adult Twins (GOSAT): a multimodal investigation of personality, temperament and cognitive ability.

The German Observational Study of Adult Twins (GOSAT) is the largest population-based observational twin study in Germany to date. Embedded in the Bielefeld Longitudinal Study of Adult Twins (BiLSAT), it addresses the etiology of personality, temperament and cognitive ability in a sample of 300 monozygotic (MZ) and dizygotic (DZ) adult twin pairs between 18 and 70 years of age. A major aim of the GOSAT lies in the utilization of different modes of measurement, (i.e., peer reports and observational data), in addition to self-reports which have been used predominantly in past behavioral genetic research on personality and temperament in adults. Participants completed a full day assessment at the University of Bielefeld including videotaped social interactions and presentations, psychometric intelligence tests and computerized elementary cognitive tasks as well as objective measures and unobtrusive behavior counts. The research design of the GOSAT was devised to reduce the potential impact of systematic rater bias on estimates of genetic and environmental influences to a minimum. In combination with extensive self- and peer report data on key personality and personality related dimensions available from the BiLSAT, the GOSAT provides a rich dataset, which currently includes DNA samples from 80% of its participants.     

Twins, chorionicity and zygosity.

Accurate determination of zygosity and chorionicity is essential in all multiple maternities. The parents and the multiples themselves ask it. It is of medical importance and now considered as a prerequisite in several domains of twin research, especially when perinatal data are analysed. It helps the multiples and their parents and teachers to ascertain identity. The methods are briefly described and a plea is made to obstetricians and paediatricians to use them systematically at the time of birth.     

Minocycline modulates human social decision-making: possible impact of microglia on personality-oriented social behaviors

Background

Microglia, one of the glial cells, play important roles in various brain pathologies including psychiatric disorders. In addition, microglia have recently been proved to monitor synaptic reactions via direct-touching even in normal brain. Human microglia may modulate various social/mental functions, while microglial social/mental roles remain unresolved especially in healthy humans. There is no known drug with the specific effect of modulating microglia. Therefore, using minocycline, a tetracycline antibiotic and the most famous microglial inhibitor, is one of the best alternative approaches to clarify microglial functions on human social/mental activities.

Methodology/Principal Findings

We conducted a double-blind randomized trial of trust game, a monetary decision-making experiment, with ninety-nine human adult males who decided how much to trust an anonymous partner after a four-day administration of minocycline. Our previous pilot trial indicated a positive effect of minocycline, while the underlying mechanisms were not clarified. Therefore, in this trial with larger samples, we additionally measured the effects of anxiety and personality. The monetary score in trust game was significantly lower in the minocycline group. Interestingly, participants’ ways of decision-making were significantly shifted; cooperativeness, one component of personality, proved to be the main modulating factor of decision-making in the placebo group, on the other hand, the minocycline group was mainly modulated by state anxiety and trustworthiness.

Conclusions/Significance

Our results suggest that minocycline led to more situation-oriented decision-making, possibly by suppressing the effects of personality traits, and furthermore that personality and social behaviors might be modulated by microglia. Early-life events may activate human microglia, establish a certain neuro-synaptic connection, and this formation may determine each human’s personality and personality- oriented social behaviors in later life. To explore these mechanisms, further translational research is needed.

Trial Registration

UMIN clinical trial center UMIN000004803     

Toward understanding how early-life social experiences alter oxytocin- and vasopressin-regulated social behaviors

The early-life social environment has profound effects on brain development and subsequent expression of social behavior. Oxytocin and vasopressin are expressed and released in the brain and are important regulators of social behavior. Accordingly, the early social environment may alter social behaviors via changes in the oxytocin and/or vasopressin systems. To test this hypothesis, and to gain mechanistic insights, rodent models mimicking either a deprived (e.g. maternal separation) or enriched (e.g. neonatal handling) early social environment have been utilized. Findings indeed show that differences in the quality of the early social environment are associated with brain region-specific alterations in oxytocin and vasopressin expression and oxytocin receptor and vasopressin 1a receptor binding. Early social environment-induced changes in oxytocin and vasopressin systems were associated with changes in several forms of social behavior, including maternal care, aggression, play-fighting, and social recognition. First studies provide evidence for a causal link between altered vasopressin responsiveness and impairments in social recognition in rats exposed to maternal separation and a role for epigenetic mechanisms to explain persistent increases in vasopressin expression in mice exposed to maternal separation. Overall, initial findings suggest that oxytocin and vasopressin systems may mediate early social environment-induced alterations in social behavior. Additional comprehensive studies will be necessary to advance our understanding to what extent changes in oxytocin and vasopressin underlie early social environment-induced alterations in social behavior. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.     

The co-evolution of individual behaviors and social institutions

We present agent-based simulations of a model of a deme-structured population in which group differences in social institutions are culturally transmitted and individual behaviors are genetically transmitted. We use a standard extended fitness accounting framework to identify the parameter space for which this co-evolutionary process generates high levels of group-beneficial behaviors. We show that intergroup conflicts may explain the evolutionary success of both: (a) altruistic forms of human sociality towards unrelated members of one's group; and (b) group-level institutional structures such as food sharing which have emerged and diffused repeatedly in a wide variety of ecologies during the course of human history. Group-beneficial behaviors may evolve if (a) they inflict sufficient fitness costs on outgroup individuals and (b) group-level institutions limit the individual fitness costs of these behaviors and thereby attenuate within-group selection against these behaviors. Thus, the evolutionary success of individually costly but group-beneficial behaviors in the relevant environments during the first 90,000 years of anatomically modern human existence may have been a consequence of distinctive human capacities in social institution building.     

社会行为发育的行为神经内分泌效应

发育过程中行为神经内分泌环境能够调节解剖和生理的长期变化,产生深远的行为效应,所以神经内分泌环境在幼体发育及其行为生理特征的形成中起重要作用。本文综述了神经垂体激素、类固醇激素及它们的受体在社会行为发育中的行为神经内分泌效应;指出该领域有待解决的问题和进一步研究的方向;希望能使人们重视人类发育过程中双亲行为和激素作用对儿童社会行为及其相关神经内分泌特征的影响。     

Internet-based cognitive behavior therapy vs. cognitive behavioral group therapy for social anxiety disorder: a randomized controlled non-inferiority trial

Background and Aims

Cognitive behavioral group therapy (CBGT) is an effective, well-established, but not widely available treatment for social anxiety disorder (SAD). Internet-based cognitive behavior therapy (ICBT) has the potential to increase availability and facilitate dissemination of therapeutic services for SAD. However, ICBT for SAD has not been directly compared with in-person treatments such as CBGT and few studies investigating ICBT have been conducted in clinical settings. Our aim was to investigate if ICBT is at least as effective as CBGT for SAD when treatments are delivered in a psychiatric setting.

Methods

We conducted a randomized controlled non-inferiority trial with allocation to ICBT (n = 64) or CBGT (n = 62) with blinded assessment immediately following treatment and six months post-treatment. Participants were 126 individuals with SAD who received CBGT or ICBT for a duration of 15 weeks. The Liebowitz Social Anxiety Scale (LSAS) was the main outcome measure. The following non-inferiority margin was set: following treatment, the lower bound of the 95 % confidence interval (CI) of the mean difference between groups should be less than 10 LSAS-points.

Results

Both groups made large improvements. At follow-up, 41 (64%) participants in the ICBT group were classified as responders (95% CI, 52%–76%). In the CBGT group, 28 participants (45%) responded to the treatment (95% CI, 33%–58%). At post-treatment and follow-up respectively, the 95 % CI of the LSAS mean difference was 0.68–17.66 (Cohen’s d between group = 0.41) and −2.51–15.69 (Cohen’s d between group = 0.36) favoring ICBT, which was well within the non-inferiority margin. Mixed effects models analyses showed no significant interaction effect for LSAS, indicating similar improvement across treatments (F = 1.58; df = 2, 219; p = .21).

Conclusions

ICBT delivered in a psychiatric setting can be as effective as CBGT in the treatment of SAD and could be used to increase availability to CBT.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00564967","term_id":"NCT00564967"}}NCT00564967