Temperament

Groundwork was laid for research on temperament in childhood by Alexander Thomas, Stella Chess, and their colleagues in the New York Longitudinal Study (Thomas et al. 1963). They analyzed interviews with parents about behaviors of their two-to-six-month-old infants, and identified nine dimensions of temperament: activity level, approach/withdrawal to new situations, adaptability to the desires of the parent, mood (positive versus negative), threshold, intensity, distractability, rhythmicity, and attention span/persistence.

Major revisions to this list have been proposed, based on factor analytic research on children's temperament. Factor analysis examines correlations among items or variables to determine which items or scales cluster together and which are relatively unrelated. The list of temperament dimensions in infancy and early childhood includes activity level, positive affectivity, fearfulness, anger/frustration, and by early childhood, effortful control (Rothbart and Mauro 1990). Effortful control refers to the capacity to inhibit a dominant response, such as opening a present, in order to perform a less dominant response, such as waiting for the appropriate occasion.

Studies of temperament in childhood have identified three broad factors of individual differences (Rothbart and Bates 1998). The first is surgency or extraversion, including activity level, high-intensity pleasure (risk seeking), impulsivity, positive excitement, smiling and laughter, and low shyness. The second is negative emotionality, including discomfort, sadness, anger/frustration, fear, and low soothability. The third is effortful control, including inhibitory control, attention, perceptual sensitivity, and low-intensity pleasure. Data on a large sample of toddlers in the Australian Temperament Project have yielded broad factors of negative emotionality, self-regulation, and sociability (Prior et al. 1989) that are very similar to negative emotionality, effortful control, and extraversion/surgency.