Story of Psychology - Morton Hunt [221]
There are a number of factors that would have to be considered in a full discussion of why so much co-variation is observed, but for most psychologists the explanation has seemed to lie in the fact that Sheldon himself executed both sets of ratings. Consequently, one may reason that implicitly Sheldon’s prior convictions or expectations in this area led him to rate both physique and temperament in a consistent manner, whatever may have existed in reality.71
Supporters of Sheldon’s views sought to repair this shortcoming in later studies; they had the somatotype ratings made from photographs by raters who never met the individuals, and the personality evaluations made by other raters from questionnaire data rather than interviews. These studies confirmed Sheldon’s connections between body type and personality, but with considerably smaller correlations.72 Even these data, however, might not prove a direct link between somatotypes and personality; the link could be indirect and social. Because people expect strong muscular mesomorphs to be leaders, weak skinny ectomorphs to avoid physical competition and rely on their minds, children, sensing what people expect of them, may come to behave accordingly.73
Although the somatotype theory attracted attention and sparked much research during the 1950s, the trenchant criticisms of it, and the fact that the theory was hereditarian and thus out of tune with the prevailing liberalism of the time, caused it to fade in influence. By the 1960s, according to the distinguished historian of American psychology Ernest Hilgard, it had almost vanished from the scene. But stronger evidence of the innateness of personality, or of at least a predisposition toward one pattern or another, has continued to crop up.
In the 1940s, Alexander Thomas and Stella Chess, psychiatrists at the New York University Medical Center, began studying individual temperamental differences in infants and young children. (“Temperament,” a part of personality, is the individual’s characteristic way of reacting emotionally to stimuli and situations.) Thomas and Chess collected data on babies’ behavior starting at birth, partly by personal observation and partly by asking parents specific questions, such as how the infant reacted to the first bath or the first mouthful of cereal. They found good evidence of what every mother of more than one child knows, namely, that infants are temperamentally different from one another from their first hours on.
After years of study, Thomas and Chess specified nine differences that are manifest from the beginning of life. Some babies are more active than others; some have regular rhythms of eating, sleeping, and defecating while others are irregular and unpredictable; some like everything new (they gobble up the first spoonful of new food) while others do not (they spit it out); some adapt quickly to change, while others are distressed by any alteration of their schedules; some react to stimuli strongly, either laughing or howling, while others only smile or whimper; some are happy most of the time, others unhappy; some seem aware of every sight, sound, and touch, while others respond only to some stimuli and ignore others; some can be easily distracted if they are uncomfortable, but others are more single-minded; and some have a good attention span and will play with one toy for a long time, while others shift quickly from one activity to the next.
Summing up, Thomas and Chess found that about two thirds of all babies show a characteristic temperament early in infancy. Four out of ten are “easy” (placid and adaptable),