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.
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.