Kagan, Jerome2019-01-101997-02Kagan, Jerome. 1997. “Temperament and the Reactions to Unfamiliarity.” Child Development 68 (1): 139. https://doi.org/10.2307/1131931.0009-3920http://nrs.harvard.edu/urn-3:HUL.InstRepos:37980692The behavioral reactions to unfamiliar events are basic phenomena in all vertebrates. Four-month-old infants who show a low threshold to become distressed and motorically aroused to unfamiliar stimuli are more likely than others to become fearful and subdued during early childhood, whereas infants who show a high arousal threshold are more likely to become bold and sociable. After presenting some developmental correlates and trajectories of these 2 temperamental biases, I consider their implications for psychopathology and the relation between propositions containing psychological and biological concepts.en-USJournal Article2019-01-1010.2307/1131931