Although the importance of the construct is well established, unresolved conceptual issues and problems with measurement limit the applicability of this knowledge by practitioners. The many choices of dimensions identified as separate elements, how they should be combined, and their proper measurement given these choices constitute a continuing debate. Nevertheless, increasing use of temperament scales call for research to elaborate and refine conceptualizations to develop improved measures, and to incorporate temperament constructs in theories of personality as well as in the design of prevention and intervention strategies. However, substantial overlap found among some of these dimensions has led to questions about their validity as separate constructs. The five robust dimensions emerging from the factor analytic study of childhood temperament resemble the Big Five factors identified in the study of adult personality and suggest a temperamental underpinning to personality.
Reactivity refers to the activation of motor, affective, autonomic, and endocrine systems.
This framework broadens the possibility of identifying temperament dimensions to include those that do not appear within the first years of life. Furthermore, this approach promotes the application of research in areas such as emotion and cognition to refine temperament dimensions. One problem in the assessment of temperament is that measures for older children have been either upward extensions of temperament constructs and scales derived from observations on infants and toddlers or based on biological models without regard to development. An emphasis on early appearing traits precludes the consideration of characteristics that may be genetically programmed to emerge later in time and disregard of developmental processes excludes from consideration age-related variation in the expression of temperament. Developmental changes in the elicitors of temperamental responses such as fear or pleasure have been studied in the early years through contrived laboratory situations, but such prototypical situations at later ages remain to be determined.