Temperament refers to stable individual differences in the quality and intensity of emotional reaction, activity level, attention, and emotional self-regulation (Rothbart & Bates, 1998). Stable individual differences are the basis of temperament, but many studies have shown stability in temperament is not often found in early childhood.

Developmental milestones such as smiling, laughter, and complex emotions (e.g., guilt, shame) make it difficult to have stable measures of temperament, especially in the first year of life. It is also difficult to measure temperament because the definition and means of measuring dimensions of temperament are not universally accepted.

Thomas and Chess define temperament in terms of activity level, rhythmicity, distractibility, approach/withdrawal, adaptability, attention span and persistence, intensity of reaction, threshold of responsiveness, and quality of mood (Thomas & Chess, 1977). Rothbart defines temperament in terms of activity level, soothability, attention span/persistence, fearful distress, irritable distress, and positive affect (Rothbart, Ahadi, & Evans, 2000).

Many studies combine dimensions in their measures of temperament differently, leading to problems when comparing one study to another. Labeling children as having a “difficult temperament”, or having an “easy temperament” combines many dimensions of temperament. Difficult temperament most often refers to low soothablilty, short attention span, high irritability and may include other aspects of temperament as well.

Easy temperament usually refers to being easily soothed, high attention, low irritability and also may include other aspects of temperament. Each of the established measurement approaches (e.g., lab observations, parent-report questionnaires) has documented strengths and weaknesses. Thus, utilizing multiple approaches simultaneously is advantageous, and has been recommended by leading researchers in the field. During your time in the Infant Temperament Lab you will be able to experience multimethod data collection. You will be involved in laboratory procedures, questionnaires, and a comparison of the results of both.

“If temperament is as important as its prominence in the literature would suggest, then understanding the nature of its development should be a high priority. Such an understanding can be pursued in many ways, some of which involve collection multimethod data about other aspect of emotion, personality, and cognition in conjunction with temperament” (Lemery, K.S., Goldsmith, H., Klinnert, M., Mrazek, D., 1999).