Scientists have identified for the first time a particular gene's link to optimism, self-esteem and "mastery," the belief that one has control over one's own life — three critical psychological resources for coping well with stress and depression.
Extraversion does not just explain differences between how people act at social events. How extraverted you are may influence how the brain makes choices -- specifically whether you choose an immediate or delayed reward, according to a study.
In contrast to "every man for himself" interpretations of Charles Darwin's theory of evolution by natural selection, social scientists are building the case that humans are successful as a species precisely because of our nurturing, altruistic and compassionate traits.