Unique and relatively enduring set of behaviors , feelings, thoughts and motives that characterize and individual. Disposition to behave consistently in a particular way. Directly related to behavior and lower behavior thresholds. Transitory condition of the organism to emotions and mood that vary in intensity and uctuate over time such as anger, panic , depression and boredom. Human personality traits evolved as adaptive behavioral responses to fundamental problems of survival and reproduction. Projective tests:participant is presented with a value stimulus or siuation and asked to interpret it to tell story about what they see. Self report instruments that indicate the extent to which a person agrees or disagrees with a series of statements. Rational method: involves using reason or theory to come up with a question. Empirical method: focuses on questions that characterize the group the questionnaire is intended to distinguish. Study of how living among others in uences thought feeling and behavior.