Scientific American, pp 102-109, 1970
by Alexander Thomas, Stella Chess and Herbert G. Birch
TABLE I (abbreviated): Temperament of a child allows him to be classified as "easy", "slow to warm up", or "difficult" according to how he rates in certain categories in the authors' nine-point personality index. The categories areonly a general guide to temperament. Of the 141 subjects 65 percent could be categorized, but 35 percent displayed a mixture of traits. Such a child might for example be rated "easy" in some ways and "difficult" in others.
[Addition by J. Gruber:
||ADAPTABILITY||INTENSITY OF REACTION||QUALITY OF MOOD|
|The proportion of active periods to inactive ones||Regularity of hunger, excretion, sleep and wakefulness||The response to a new object or person||The ease with which a child adapts to changes in his environment||The energy of response regardless of its quality or direction||The amount of friendly, pleasant, joyful behavior as contrasted with unpleasant, unfriendly behavior|
|"EASY"||VARIES||VERY REGULAR||POSITIVE APPROACH||VERY ADAPTABLE||LOW OR MILD||POSITIVE|
|"SLOW TO WARM UP"||LOW TO MODERATE||VARIES||INITIAL WITHDRAWAL||SLOWLY ADAPTABLE||MILD||SLIGHTLY NEGATIVE|