Summary

The author begins with her own story of having to give a speech and resorting to gulping Bailey's Irish Cream in a bathroom stall before going on stage. The author wonders if her personality is a result of nature or nurture. She cites the work of Harvard developmental psychologist Jerome Kagan, who conducted longitudinal studies that found that babies who were "highly reactive" to stimuli grew up to be more introverted, while those who were less reactive as babies grew up to be more extroverted. Kagan's work helped link temperament, which refers to inborn traits, with personality, the constellation of features that arise as someone gets older. The more reactive babies had more active amygdalae, the emotional centers of the brain, while those who grew up to be extroverts showed less reactivity. Therefore, personality was not a result of choice but of biology...