Personality traits denote enduring individual differences among people that explain why humans are motivated differently. All traits are heritable, which means they are partly determined by genes with greater genetic similarity associated with greater trait similarity. Heritability applies to the big five personality traits of openness-to-experience, conscientiousness, extraversion, agreeableness, neuroticism, and the traits of sensation seeking, grit, and self-control plus its opposite of impulsiveness. According to the concept of trait-environment interaction because of differences in personality, people react to situations differently and are thus motivated differently. According to trait-environment correlation because of differences in personality, people select, create, or alter their situations to fit their dominant traits. These environments, in turn, also influence motivation. Furthermore, people's dominant personality traits can affect motivation over a lifetime.