Social Psychology is the scientific study of how people's thoughts, feelings, and behaviours are influenced by the actual, imagined, or implied presence of others. Social psychologists typically explain human behaviour as a result of the interaction of mental states and immediate social situations. In this book, the authors present current research on social psychology including the cultural, social and gender influences on casual sex; allostatic load based on a stress physiology model of illness; conceptualising identity within social psychology; psychological characteristics of heart disease and cancer patients; peer victimization, physical activity and social psychological adjustment in obese youth; and antisocial behaviour in children with ADHD.