Contemporary attachment research is based on the assumption that at least three types of infant attachment patterns exist: secure, avoidant, and resistant. It is not known, however, whether individual differences in attachment organization are more consistent with a continuous or a categorical model. The authors addressed this issue by applying P. E. Meehl's (1973, 1992) taxometric techniques for distinguishing latent types (i.e., classes, natural kinds) from latent continua (i.e., dimensions) to Strange Situation data on 1,139 fifteen-month-old children from the NICHD Study of Early Child Care. The results indicate that variation in attachment patterns is largely continuous, not categorical. The discussion focuses on the implications of dimensional models of individual differences for attachment theory and research.

The speech of 6 mothers to their healthy infants was examined longitudinally during the neonatal period and at 4, 12, and 24 months in a semi-naturalistic setting. Features of speech analysed were: contour of fundamental frequency, repetitiveness, timing (durations of vocalizations and pauses), tempo and MLU. The neonatal period was characterized by elongated pauses. During the 4-month period the extent of pitch contouring and repetitiveness was greater than at earlier or later ages. By 24 months, the duration of vocalizations and length of MLU became markedly greater. The period of intense face-to-face interaction around the fourth month proved to involve more changes in certain prosodic features. Some of the possible functions of these changes during this phase are discussed.

Results highlight links between different patterns (stable or decreasing) and levels (high, moderate, low, very low) of aggression across childhood and children's later adjustment. For example, even quite low aggression that is stable appears to be a risk factor for some social problems; in contrast, moderate aggression that decreases sharply to no aggression by school entry is associated with good adjustment at age 12.