Infants' emerging ability to move independently by crawling is associated with changes in multiple domains, including an increase in expressions of anger in situations that block infants' goals, but it is unknown whether increased anger is specifically because of experience with being able to move autonomously or simply related to age. To examine…

The literature reports some contradictory results on the degree of phonological specificity of infants' early lexical representations in the Romance language, French, and Germanic languages. It is not clear whether these discrepancies are because of differences in method, in language characteristics, or in participants' age. In this study, we…

Three laboratory experiments on social referencing examined whether infants' tendencies to look at and use positive information from the experimenter could be interpreted from a perspective of novelty or expertise. In Study 1, novelty was manipulated. Forty-eight 12-month-old infants participated. In a between-subject design, a more novel or a…

A microgenetic research design with a multiple case study method and a combination of quantitative and qualitative analyses was used to investigate interdyad differences in real-time dynamics and developmental change processes in mother-infant face-to-face communication over the first 3 months of life. Weekly observations of 24 mother-infant dyads…

Warning others is a paradigm case of communicative helping and prospective action understanding. The current study addressed the ontogeny of warning in infants' gestural communication. We found that 12- and 18-month-olds ("n" = 84) spontaneously warned an adult by pointing out to her an aversive object hidden in her way…

When face processing studies find sex differences, male infants appear better at face recognition than female infants, whereas female adults appear better at face recognition than male adults. Both female infants and adults, however, discriminate emotional expressions better than males. To investigate if sex and age differences in facial scanning…

Objective: Maternal antenatal anxiety is associated with an increased risk of behavioral disturbances in offspring. Recent work has suggested that the effect of maternal antenatal anxiety on infant temperament at 6 months is moderated by the serotonin transporter polymorphism 5-HTTLPR, with carriers of the short allele more susceptible to the…

In the present study, we investigated whether infants' own visual experiences affected their perception of the visual status of others engaging in goal-directed actions. In Experiment 1, infants viewed video clips of successful and failed goal-directed actions performed by a blindfolded adult, with half the infants having previously experienced…

A perturbation paradigm was employed to assess 3- and 6-month-old infants' and their mothers' sensitivity to a 3-s temporal delay implemented in an ongoing televised interaction. At both ages, the temporal delay affected infant but not maternal behavior and only when implementing the temporal delay in maternal (Experiment 1, N = 64) but not infant…

Prosocial behaviors are a diverse group of actions that are integral to human social life. In this study, we examined the ability of 18- and 24-month-old infants to engage in three types of other-oriented behaviors, specifically helping, sharing, and comforting. Infants in both age groups engaged in more prosocial behavior on trials in which an…

Using both traditional composites and novel profiles of anger, we examined associations between infant anger and preschool behavior problems in a large, longitudinal data set (N = 966). We also tested the role of life stress as a moderator of the link between early anger and the development of behavior problems. Although traditional measures of…

This study describes the development and psychometric properties of the Counseling Supervisor's Behavior Questionnaire, designed to assess the specific behaviors of supervisors, which can be observed by supervisees during supervision sessions. Factor structure, construct and concurrent validity, and internal consistency reliability of the…

This study explored variation in affective and behavioral components of infants' jealousy protests during an eliciting condition in which mother and an experimenter directed differential attention exclusively toward a rival. Variation was examined in relation to child temperamental emotionality, maternal interaction style, and attachment security.…

A behaviorally inhibited temperament in early childhood has been identified as a potential risk factor for anxiety disorders in children and adolescents. The purpose of our investigation was the development and evaluation of the factor structure, reliability and validity of the first retrospective parent report measure to assess behavioral…

Two studies with 9-, 11- and 13-month-old infants were conducted to investigate infants' ability to use an object's material properties to guide their object-directed actions. In study 1, 9- and 11-month-old infants played in an exploration phase with two objects made of different materials, one very heavy and the other one light and playable.…