This study investigated whether behavioral inhibition is best conceptualized as a continuous variable or as a distinct typology with two or more subcategories. The following data were gathered on 58 infants at 5, 7, 10, and 13 months of age; physiological functioning (cardiovascular activity and salivary cortisol); emotional expressivity in response to several stimuli; maternal perception of the infant's temperament; mother-infant interaction; and, at 13 months, behavioral inhibition, attachment security, and dependency. Scatter-plots were used to determine whether the correlation between variables was produced by extreme groups or whether it appeared similar over the range of scores. Largely similar correlation patterns and few if any mean differences would suggest that inhibition is not a categorical dimension. Results revealed very little evidence supporting a discrete perspective on behavioral inhibition as measured by the laboratory procedure; rather, most evidence appeared to be compatible with a continuous perspective. (MM)