One of my mother's favorite stories recounts a family trip to Sea World when I was four, and my brother was two and a half. We were walking through the park when suddenly, we were approached by a man dressed in a penguin costume. I jumped behind my mother and hid my face in the folds of her skirt. In the same instant, my brother zoomed forward with his arms outstretched for a hug.
My brother and I were raised by the same parents, in the same household. We both inherited my mother's brown eyes and my father's chin. So why did we have such dissimilar reactions to that penguin?
According to Dr. William B. Carey M.D., the reason is likely due to differences in our temperaments. Carey is an attending physician in the division of General Pediatrics at the Children's Hospital of Philadelphia, and clinical professor of pediatrics at the University of Pennsylvania School of Medicine. Much of the information in this article comes from Carey's best selling book Understanding Your Child's Temperament.