The modem history of temperament research began in the late 1950s with the New York Longitudinal Study conducted by Alexander Thomas, Stella Chess, and their colleagues. Twenty-five years later, temperament has become a major focus of research on early-developing emotional and social traits. For example, a computer search of Psychological Abstracts shows that since 1970 the number of articles on temperament has increased by 50% each 5 years. From 1970 through 1974, 26 articles with the word temperament in the title or abstract were published per year on the average. During the second half of that decade, approximately 42 articles appeared each year. The rising trend continues in the 1980s: From 1980 to 1983, 62 articles on temperament were published on average each year.

The impetus for this growth in temperament research stems from the merging of several shifts in child development research: from a view of the child as passive to a model of the child as an active, transacting partner with the environment; increasing interest in individual differences in development; an expansion of research on emotional and social development; and a clear change from an exclusive reliance on environmental explanations of developmental differences to a more balanced perspective that recognizes the possibility of biological as well as environmental influences. Most stimulating is the multidisciplinary flavor of temperament research-clinicians, infancy researchers, cultural anthropologists, and behavioral geneticists have, each for their own reasons, been drawn to the study of temperament.