Adults often attribute internal dispositions to other people and down-play situational factors as explanations of behavior. A few studies have addressed the origins of this proclivity, but none has examined emotions, which rank among the more important dispositions that we attribute to others. Two experiments (N = 270) explored 15-month-old…

We assessed developmental stability and context generalizability of temperament in pigtailed macaques ("Macaca nemestrina") from the University of Washington Infant Primate Research Lab. A principal components analysis condensed 6 behavioral measures into 2 components, interpreted as reactivity and boldness. Changes in these measures over the 1st…