Biological Contribution to Social Influences on Alcohol Drinking: Evidence from Animal Models

Social factors have a tremendous influence on instances of heavy drinking and in turn impact public health. However, it is extremely difficult to assess whether this influence is only a cultural phenomenon or has biological underpinnings. Research in non-human primates demonstrates that the way individuals are brought up during early development affects their future predisposition for heavy drinking, and research in rats demonstrates that social isolation, crowding or low social ranking can lead to increased alcohol intake, while social defeat can decrease drinking. Neurotransmitter mechanisms contributing to these effects (i.e., serotonin, GABA, dopamine) have begun to be elucidated. However, these studies do not exclude the possibility that social effects on drinking occur through generalized stress responses to negative social environments. Alcohol intake can also be elevated in positive social situations, for example, in rats following an interaction with an intoxicated peer. Recent studies have also begun to adapt a new rodent species, the prairie vole, to study the role of social environment in alcohol drinking. Prairie voles demonstrate a high degree of social affiliation between individuals, and many of the neurochemical mechanisms involved in regulation of these social behaviors (for example, dopamine, central vasopressin and the corticotropin releasing factor system) are also known to be involved in regulation of alcohol intake. Naltrexone, an opioid receptor antagonist approved as a pharmacotherapy for alcoholic patients, has recently been shown to decrease both partner preference and alcohol preference in voles. These findings strongly suggest that mechanisms by which social factors influence drinking have biological roots, and can be studied using rapidly developing new animal models

Group member prototypicality and intergroup negotiation: How one's standing in the group affects negotiation behaviour

How does a representative's position in the group influence behaviour in intergroup negotiation? Applying insights from the social identity approach (specifically self-categorization theory), the effects of group member prototypicality, accountability and group attractiveness on competitiveness in intergroup bargaining were examined. As representatives of their group, participants engaged in a computer-mediated negotiation with a simulated out-group opponent. In Experiment I (N = 114), representatives with a peripheral status in the group sent more competitive and fewer cooperative messages to the opponent than did prototypical representatives, but only under accountability. Experiment 2 (N = 110) replicated this finding, and showed that, under accountability, peripherals also made higher demands than did prototypicals, but only when group membership was perceived as attractive. Results are discussed in relation to impression management and strategic behaviour