Used multilevel analyses to examined the amounts of time infants spent asleep, awake, content, feeding, fussing, and crying at 2, 6, 12, and 40 weeks of age. Found that day-to-day fluctuations accounted for between 44 and 53% of the variance in amounts of time sleeping, fussing, and crying. (MDM)

Discusses Adolph's research on locomotion with regard to the requirements of an ecological psychology, especially the use of control laws; her examination of individual styles and normative patterns as it reflects a dynamic systems perspective; and her use of cognitive processes of decision making in explaining why infants approach or avoid a…

Examined whether early individual differences in look duration were related to general mechanisms of the infant nervous system combining attention and emotion. Found significant positive correlations between attention measures and duration of facial expressions of pain/distress after vaccinations at 3, 5, and 11 months. Concluded that individual…

Explored genetic and environmental underpinnings of temperamental differences in 3- to 16-month-old twins and their parents. Found that additive genetic and shared environmental effects best represented smiling, laughter, and duration of orienting. Shared environmental effects fully accounted for co-twin similarity for soothability. Additive…

Examined 8- to 10-month-olds' responses to standard procedures eliciting joy, fear, anger, and discomfort. Found that response parameters to standard procedures cohered strongly within each episode. Responses cohered across same-emotion episodes, except for anger. Responses and father-reported temperament related to infant's emotional tone in…

Investigated whether individual and developmental differences in look duration were correlated with latency to disengage fixation from a visual stimulus for 3- and 4-month olds. Found that look duration was correlated with disengagement latency. Three-month olds showed slower latencies than 4-month olds. Long-looking infants showed greater…

This paper discusses the development of instruments to measure individual differences in behavior during infancy. The Infant Temperament Questionnaire (ITQ), which was designed to measure the temperament dimensions identified by the New York Longitudinal Study (NYLS), constituted the methodological starting point in the search for a dimensional…

Focusing on infants' physical attractiveness and behavior, this study explores reasons some infants receive greater amounts and different types of attention from adults than do others. Subjects were observed in 21 groups of three, consisting of one adult and two same-sex infants. Adult subjects were unmarried, childless undergraduate women…

Disputes claims concerning the association between strange-situation behavior around 12-20 months of age and subsequent child performance. Maintains studies have precluded causal inferences about the direction and nature of effects, finding associations only when the quality of care received was stable, thus, precluding inferences about the…

Study of children aged 21 to 31 months tentatively concludes: (1)behavioral tendency to be inhibited or uninhibited with unfamiliar people or during unfamiliar events is moderately stable across time and context; and (2)moderately negative relationship exists between behavioral inhibition and heart rate variability, and positive relationship…

Combinatorial abilities in language and elicited symbolic play were compared in a longitudinal study of 30 children at 20 and 28 months. In addition, multivariate analyses were used to assess the stability of individual differences. Generally, different symbolic play variables contributed unique explained variance to different language variables.…

Twenty-five infants were tested every two weeks on the AB Object Permanence Task, from the time they first reached for a hidden object until they were 12 months old. Results indicate that the AB provides an index of the ability to carry out an intention based on stored information despite a conflicting habitual tendency. (Author/RH)

Author discusses the different contexts in which the concept of state is used, drawing on examples from her own research with newborns. (MB)

Examines strategies for studying individual differences in infant behavior from the standpoints of the distinction between individual differences and developmental function and the need to study change with multivariate techniques. These themes are applied to the study of mental development, behavior genetics, temperament, and attachment. (RJC)