If western culture has an effect on amount of sleep/sleep style. Sleep is more influenced by biological clocks rather than situational reasons. Thriving in the 1920"s: psychoanalytic theories prominence, no empirical data, no lasting contribution. Challenge of trait theory b cultural psychologists: traits are an invention of western culture, even stronger effect of situation in non-western cultures, no empirical evidence. Modern research: looking for cultural influences on personality in cross-national comparisons. Within nation studies fail to reveal the influence of culture on personality. Cross national studies can reveal effects of culture on personality. In a cross-cultural study, how much of the variance in personality (big five) is bw nations (vs variation w/n nations): answer:0-20% Culture: common social practices (universal health care, prevalent beliefs, values, norms (love hockey) Most studies compare national averages to study culture. Other studies try to relate cultural variables to personality: individualism. Freedom of choice, following own values more important than tradition.