Brief History of Temperament Concepts
Almost since writing began, authors wrote about characters with different temperaments. To the Greeks, temperament depended on the proportion of 4 bodily fluids (humors): blood (cheerfulness), phlegm (sluggishness or apathy), black bile (gloominess) and yellow bile (anger). In China, temperament traits were described in terms of natural elements: water (flexible, artistic); wood (routine, solid); metal/gold (strong, cool); fire (strong emotions); earth (nurturing).
In the western Middle Ages, explanations of temperament took a more judgmental, religious turn. The depressed, angry, "bilious" child was more likely to be seen as wicked or "possessed." In the more scientific view of the 17th century, individual differences were seen as the result of the environment and sensory experiences. The mind was a blank slate or "tabula raza." People reacted differently because life experiences had created different viewpoints. This belief continued into the 19th century. Freud, having trained in physiology, believed that human behavior was partly motivated by unconscious survival needs. However, his psychoanalytic theory also taught that individual behavior differences were strongly affected by early experiences in life.
In the early 20th century, behavioral psychologists continued to believe that behavior was mainly learned rather than inborn. Children learned behavior patterns according to the positive or negative reactions they received from their surroundings, especially their parents. A variety of events slowly changed this perception. Scientists studying animal behavior found that temperament was hard to ignore. They saw that a number of behavioral styles remained stable across generations of laboratory animals. And clinicians found that "difficult" children often came from "good" families and (even harder to explain) apparently well-adjusted children often came out of very chaotic and difficult conditions.
Drs. Stella Chess and Alexander Thomas are the clinician-researchers who deserve the credit for finally turning the light back onto inborn temperament. Starting in the 1950s, their New York Longitudinal Study followed 131 children from birth into their thirties and confirmed the importance of temperament differences. Particularly important were the ways those differences did or did not "fit" or match well with the child's environment. Since Chess and Thomas, many additional studies in psychology, psychiatry and genetics have confirmed that the interaction between inborn traits and the environment greatly affect the life course of each child.