This article attempts to illustrate the value of a psychobiological approach to the study of a particular behavior; in this case, vocalization of infant primates following loss of the mother. (PCB)

Capacity of infant monkeys to mount an antibody response to viral challenge was evaluated after monkeys' removal from their mothers in several social and physical environments. Results indicated that trauma of separation was reduced when infants were familiar with the separation environment or familiar social companions were available. (PCB)

This article reviews the literature and presents data on sensory deprivation stress and supplemental stimulation of the rat pup and the preterm neonate. (PCB)

The Brazelton Neonatal Behavioral Assessment Scale with Kansas Supplement was administered to 60 newborns who were classified as extremely healthy or as having slight perinatal problems. Correlations between behavioral responding on the assessment scale and levels of plasma cortisol (obtained from blood tests) were examined. (PCB)

Longitudinal study of two cohorts of children selected in the second or third year of life as being extremely cautious and shy (inhibited) or fearless and outgoing (uninhibited) in regards to unfamiliar events revealed preservation of these two behavioral qualities through their sixth year. (PCB)

Following a brief consideration of the nature of "stress" as implied in the articles in this special section, the possible role of biological measurements in the study of behavioral development is examined. (PCB)

A neurobehavioral maturity assessment which used data from preterm infants was developed. Eight dimensions of neurobehavioral functioning were found to be stable, nonredundant, and developmentally valid. (PCB)

The behavioral dynamics of three different types of early mother-infant interactions were examined. Mothers were instructed to play with, imitate, and hold the attention of their infants. Frequency of vocalization, gaze direction, and smiling by both interactants, tactile play by the mother, and crying by the infant were recorded. (PCB)

Newborn status, ratings of temperament, and experiential (parenting) antecedents of hyperactivity were evaluated in a longitudinal investigation. Experiential variables included maternal intrusive care, seductive behavior towards child, and overstimulation of child. (PCB)

The relation between resumption of full-time employment by mothers of infants, and subsequent infant-mother and infant-father attachments, was examined. No relation emerged between maternal work status and the quality of infants' attachments to their mothers. (PCB)

Results indicated that the more frequently the children studied expressed emotion, the older the age of language achievements; and the more time spent in neutral affect, the younger the age of language achievements. (PCB)

Changes in children's categorization behavior between 15 and 21 months of age and the relation of these changes to developments in language, object permanence, and means-end understanding are reported. (PCB)

Studies children's inductive inferences in order to investigate the development of the expectation that members of a category share unforeseen properties. Results indicate that preschoolers drew more inferences based on category membership than on perceptual appearances. (PCB)

To investigate the development of function concepts and their relation to mathematical and logical abilities typically acquired during the age period of five to seven years, children were tested on nonnumerical function tasks, numerical tasks, and aspects of logical reasoning. (PCB)

Normally developing and mildly developmentally delayed preschool-age boys were brought together to form playgroups. Videotapes of the groups and peer sociometric ratings indicated that delayed children had a deficit in peer-related social interactions and were seen as less competent and of lower social status by peers. (PCB)