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Genetics, Social Behaviors, Social Environments and Aging

studies of human sociality. Progress in understanding the causes and consequences of human social behavior is advancing through highly integrative science and predicated on the recognition that many social behaviors have a biological basis. Social behaviors, and the environments constructed by such behaviors, are central to the evolution of species. How patterns of social behaviors evolve has long been an intense area of research in its own right. In more recent years a significant literature has emerged documenting that human social environments, ranging from larger sociocultural factors and neighborhoods (Berkman & Kawachi, 2000; House et al., 1988; Marmot, 2006; Wen et al., 2006) to interpersonal relationships (Hawkley et al., 2006; Ryff et al., 2001), influence physical and psychological health throughout life. An extensive array of research has begun to identify biomarkers and elucidate pathways likely to be involved (Hawkley et al., 2006; Kiecolt-Glaser et al., 2005; McDade et al., 2006; Meyer-Lindenberg & Weinberger, 2006; Ryff & Singer, 2005; Uchino et al., 1996). This collection of work suggests that social environments may figure prominently in gene–environment interactions (Hernandez & Blazer, 2006; Ryff & Singer, 2005) and a growing number of studies are confirming this, particularly in the area of psychopathology (Rutter, 2007; Rutter et al., 2006). Bringing cutting-edge behavioral genetics research to bear on questions of social behaviors, social environments and aging marks a high priority area of program development at the Behavioral and Social Research (BSR) program at the National Institute on Aging (NIA). This theme has been explored and promoted through a series of workshops and other activities (Harris, 2005).This special issue entitled Genetics, Social Behaviors, Social Environments and Aging is part of that initiative and features a range of research from various twin and nontwin studies investigating social behaviors and social environments. In very broad strokes, three lines of inquiry are generating findings critical to understanding genes, social behaviors and social environments. First, concerns genetic influences on social behaviors; second, is the interplay between genes with social behaviors and social environments; and third, relies on the integration of biodemography, population genetics and evolution to explore how the social and demographic histories of populations have shaped gene pools and genomic structure. Detailing research in these three areas is beyond the scope of this introduction, but some important findings and directions are highlighted below to help frame how the field is moving forward.