The rise of interest in temperamental qualities has raised the consciousness of investigators regarding the best way to conceptualize and to measure this dass of psychological characteristics. The tension surrounding conceptualization turns on the difference between a continuous trait compared with a discrete category. For example, one can regard a temperament al characteristic, like approach-withdrawal, as continuous, and to treat extremely shy and extremely sociable children as belonging on a single dimension. The implication of this assumption is that the processes that mediate a very sociable child are the complements of those that produce a very shy child.