Infant motor development is affected by the sociocultural context in which it takes place. Because societal and cultural practices are dynamic, this exploratory study examined whether the ages at which infants typically learned to crawl, cruise, and walk changed over the past 3 decades. We compiled archival data from 1,306 infants born between…

How do age and the acquisition of independent walking relate to changes in infants' everyday experiences? We used a novel ecological momentary assessment (EMA) method to gather caregiver reports of infants' restraint, body position, and object holding via text messages sparsely sampled across multiple days of home life at 10, 11, 12, and 13 months…

Early exploratory behaviors have been proposed to facilitate children's learning, impacting motor, cognitive, language, and social development. This study related the performance of behaviors used to explore oneself to behaviors used to explore objects, and then related both types of exploratory behaviors to motor, language, and cognitive measures…

Dysregulation of diurnalcortisol rhythms is often seen among children exposed to early adversity and has been associated with a variety of negative physical and mental health outcomes. The present study examined whether two indicators of deprivation, sociodemographic burden and observed parental insensitivity, were associated with child diurnal…

The present study examined genetic, prenatal, and postnatal environmental pathways in the intergenerational transmission of anxiety and depressive symptoms from parents to early adolescents (when these symptoms start to increase), while considering timing effects of exposure to parent anxiety and depressive symptoms postnatally. The sample was…

We assessed whether the negative association between maternal postpartum depression (PPD) and infants' development of joint attention (gaze following) generalizes from WEIRD (Western, Educated, Industrialized, Rich, and Democratic) to Majority World contexts. The study was conducted in Bhutan (N = 105, M = 278 days, 52% males) but also draws from…

Dance is a universal human behavior and a crucial component of human musicality. When and how does the motivation and tendency to move to music develop? How does this behavior change as a process of maturation and learning? We characterize infants' earliest dance behavior, leveraging parents' extensive at-home observations of their children.…

The second year of life is a time of formative developmental change as basic behavioral systems undergo rapid integration and expansion. This study examined the developmental trajectories of social-emotional (SoE) outcomes and the effects of infant sex and household chaos (HC) on the development of SoE outcomes across the second year of life. The…

Recent years have seen a rise in the popularity of eye-tracking methods to evaluate infant and toddler interpretation of visual stimuli. The application of these methods makes it increasingly important to understand the development of infant sensitivity to the perceptual properties implicated in such methods. In light of recent studies that…

New motor skills supply infants with new possibilities for action and have consequences for development in unexpected places. For example, the transition from crawling to walking is accompanied by gains in other abilities--better ways to move, see the world, and engage in social interactions (e.g., Adolph & Tamis-LeMonda, 2014). Do the…

Infants can help and share in the second year of life. However, there is limited knowledge as to variability in these behaviors as a function of target (e.g., caregiver vs. unfamiliar adult) and the influence of caregiver support on infant prosocial behavior. Infants (N = 268, 124 female) at 1-2 years of age (M = 1.47, SD = 0.27) and again at 2-3…

As they develop into mature speakers of their native language, infants must not only learn words but also the sounds that make up those words. To do so, they must strike a balance between accepting speaker-dependent variation (e.g., mood, voice, accent) but appropriately rejecting variation when it (potentially) changes a word's meaning (e.g., cat…

Emotions remain something of a mystery for most of us even when we accept their centrality to development in general and to infancy in particular. I make 2 arguments in this paper. One: that the most crucial thing about emotions is that they allow mutuality of engagement with other emotional beings--not only evoking responses, but also provoking…

Early mother-infant coordinated interactions play a critical role in infant development. The present study describes the development of the dyadic coordination of vocalization and gaze behavior between mothers and infants over the first year of life. In addition to describing developmental trajectories of behavior, the study contributes to our…

Past research has shown a discrepancy in young infants' use of height information in occlusion and containment events--a pattern typically accounted for by event categorization and rule learning. Broadening these theories, the present experiment examined the role of comparison in young infants' reasoning about physical events. We rotated a typical…