Galen's Prophecy

by Jerome Kagan

Nearly two thousand years ago a physician called Galen of Pergamon suggested that much of the variation in human behavior could be explained by an individual's temperament. Since that time, ideas about inborn dispositions have fallen in and out of favor. Based on fifteen years of research, Galen's Prophecy now provides fresh insights into these complex questions, offering startling new evidence to support Galen's ancient classification of melancholic and sanguine adults. Two of the most obvious personality traits in children, as well as adults, are a cautious compared with a spontaneous approach to new people and situations. About 20 percent of healthy infants born to loving families come into the world with a physiology that renders them easily aroused by new experiences and, when aroused, to become distressed. A majority of these high-reactive infants become fearful, cautious children. A larger group, about 40 percent of infants, are born with a different physiology that leads them t