An individual's temperament is his or her style; temperament describes the way in which an individual behaves or does something, not the action he or she carries out. Thomas and Chess (1977), described nine factors that compose temperament: activity level, adaptability, approach/withdrawal, attention span and persistence, distractibility, intensity of reaction, quality of mood, regularity, and threshold of responsiveness.

The biological view of temperament was given greater impetus by Buss and Plomin (1984), who argued that to be considered a temperament, a behavioral predisposition must be present in adults, and must be developmentally stable, adaptive, and have a genetic component. Emotionality, activity, sociability, and impulsivity, then, are dimensions of temperament. Temperament is the dimensions of an individual's personality that are largely present at birth, exist in most historical ages and most societies, are consistent across settings, and are stable as the individual develops (Plomin, 1983). Temperament is an individual variation that is biological or constitutional, remains with the individual, and is linked to differences in behavioral or expressive style.

Temperament, as an individual variation, can be a significant factor in identification as having an emotional/behavioral disorder. Thomas and Chess (1977) suggest that the "goodness of fit" of the individual's temperament and the environment can be a major factor in problem behavior. Temperament may also affect a child's learning by determining the ease and speed with which attention and activity may be modulated and directed.

According to Martin (1992a), there is a limited, though significant, body of research on the relationship between child characteristics in the social, emotional, and attentional domains, collectively referred to as "temperamental characteristics," and the educational process and outcomes for learners with disabilities. He reviews the research in the relationships between temperament and the characteristics of learners with disabilities such as Down syndrome, neurological disabilities, learning disabilities, hyperactivity, and behavior problems; family interactions; teachability, or teacher attitudes toward learners; teacher decision making; and classroom interaction. Martin presents a model of the effects of temperament on educational outcome, mediated by their effects on parents, peers, and teachers.

In Martin's model, temperament is one of the factors that functions across home and school settings and affects learning and school behavior. A child's temperament, he suggests, is manifest in classroom behavior, which affects peer attitudes and behavior, which in turn have an additional impact on the child's educational outcome. These peer attitudes and behavior toward a learner identified as emotionally/behaviorally disordered may have additional impact because of the increased risk for social rejection (Janke & Lee, 1991). Children who are perceived to have a "difficult temperament" are particularly at risk for social relationship problems (Martin, 1992a).

Although there may be a relationship between the temperament of parent and child, Martin (1992b) suggests that parents and their children will always differ in temperament in that they are at different developmental stages, share only half of their genetic material, and are responding to different demands. The goodness of fit between the temperaments of parent and child is an important determiner of the child's development.