Temperament

While researchers tend to agree on the basic definition of temperament, they differ on the types of temperament styles they investigate. According to McCall, most temperament studies focus on four dimensions: activity, reactivity, emotionality, and sociability. Activity is the intensity and rate of a child's movement and speech. How much does the child move around during play or at her desk at school? Reactivity is the intensity of a child's approach or withdrawal from a situation and how long the child is interested in and stays in the situation. How much does a child withdraw from novel toys or new situations? Emotionality is the degree to which a child expresses negative or positive emotions and how often she expresses them. Does a child get upset easily or become angry quickly? Sociability is the tendency to initiate social contact and the preference to be with others. Is the child friendly?

Not all temperament characteristics fit neatly into these four dimensions. Shyness, for example, has been investigated as an aspect of reactivity (i.e., the tendency to withdraw from new social situations) and as the opposite end of sociability (i.e., the tendency to not want to be around people). While many researchers have focused on one or more of these dimensions, others have categorized children based on combinations of traits and styles.

Thomas and Chess divided children into three categories based on nine temperament dimensions: activity level, approach-withdrawal in new situations, adaptability, threshold of responsiveness, intensity of reactions, quality of mood, distractibility, persistence, and rhythmicity of biological functions (e.g., sleeping, feeding, needing to be changed). They were interested in the "goodness-of-fit" between the children's characteristics and their social environments. Forty percent of the children in their study were classified as "easy" babies. These children adapted easily to new situations, were sociable and playful, and had regular biological functions. These children were not too reactive or emotional, and so they were easy to parent. Another 15 percent of the babies fell into the "slowto-warm-up" category. These children withdrew from new situations somewhat, took a little longer to adapt to environments, and were less active. They needed more attention and time compared to easy babies, but they adapted to their surroundings without too much trouble. About 10 percent of the infants were classified in the "difficult" temperament category. Children with difficult temperaments were very emotional, had irregular biological functions, and had intense negative reactions to new situations. These children were the most difficult to parent and required a great deal of effort, time, and patience. The remaining children fell into more than one category or could not be classified.

Dimensions of temperament are measured in a variety of ways. Parents are interviewed about their children's behavior at home, and teachers are interviewed about the children's behavior at school. Depending on the dimension being assessed, these adults may be asked about children's reactions to new toys or people (i.e., reactivity) or about their energy levels (i.e., activity). Parent and teacher reports of children's behavior may be limited to that context and influenced by their own perceptions of the world (i.e., they may be biased). So, scientists also use behavioral and observational methods to assess children's temperament. Activity level in infancy, for example, can be measured using a device that measures the number of times a baby's arms and legs move. Most of the time, trained researchers observe the children at home, at school, or in a novel environment (e.g., a playroom in a researcher's laboratory). Coders look for visible signs of the child's underlying temperament style. For example, a child who approaches an unfamiliar student on a school playground and talks to the new child would be coded as high in sociability.

Some dimensions of temperament have to be assessed in specific contexts. Reactivity and shyness, for instance, must be observed in novel situations because the behavior of interest may not appear in familiar contexts or may appear for only some children. For example, children who are withdrawn in unfamiliar situations are considered temperamentally shy. Children who are withdrawn in both familiar and unfamiliar situations, on the other hand, are considered anxious and possibly at risk for developing an anxiety disorder. Sometimes children's behavior is ambiguous, so researchers will measure changes in children's physiology as well. Shy children, for instance, tend to experience a higher heart rate when they are in new situations compared to when they are at home. Children are also asked to report their perceptions of their temperament style after around the age of eight. This is when most children are able to report their own behaviors and preferences in a reliable manner. Few studies, however, include self-report measures because most temperament studies focus on children in infancy and early childhood.