5) Manke, B., Saudino, K.J., & Grant J.D. (2001). Extremes Analyses of Observed Temperament Dimensions. In R. Emde & J. Hewitt (Eds.), Infancy to Early Childhood: Genetic and Environmental Influences on Developmental Change (pp 52-72). Oxford University Press: New York, New York.

This chapter examines the origins of membership in extreme high and low temperament groups, as defined by scores on observational measures of shyness, activity, affect-extraversion, task orientation and behavioral inhibition at 14, 20, and 24 months of age. Examining temperament from an extremes approach may be valuable to the study of psychopathology, which can be characterized as extreme or pathological manifestations of normal personality. In this study, researchers found that the causes of extreme group membership (both high and low) across several dimensions of temperament are not quantitatively, but rather qualitatively different than factors that influence individual differences in the population. One notable exception was the origin of low behavioral inhibition at 14 months of age.