Children raised in chaotic households show affect dysregulation during later childhood. To understand why, we took day-long home recordings using microphones and autonomic monitors from 74 12-month-old infant-caregiver dyads (40% male, 60% white, data collected between 2018 and 2021). Caregivers in low-Confusion Hubbub And Order Scale (chaos)…

Does knowledge of other people's minds grow from concrete experience to abstract concepts? Cognitive scientists have hypothesized that infants' first-person experience, acting on their own goals, leads them to understand others' actions and goals. Indeed, classic developmental research suggests that before infants reach for objects, they do not…

Research with Western samples has uncovered the rapid development of infants' visual attention. This study evaluated spatial attention in 6- to 9-month-old infants living in rural Malawi (N = 511; n[subscript Boys] = 255, n[subscript Yao] = 427) or suburban California, United States (N = 57, n[subscript Boys] = 29, n[subscript White] = 37) in…

Joint attention (JA) is the purposeful coordination of an individual's focus of attention with that of another and begins to develop within the first year of life. Delayed, or atypically developing, JA is an early behavioural sign of many developmental disabilities and so assessing JA in infancy can improve our understanding of trajectories of…

New motor skills can shape how infants communicate with their caregivers. For example, learning to walk allows infants to move faster and farther than they previously could, in turn allowing them to approach their caregivers more frequently to gesture or vocalize. Does the link between walking and communication differ for infants later diagnosed…

It is known that infant-directed speech (IDS) plays a key role in language development. Previous research, however, has also identified significant variability across societies in terms of how often IDS occurs. For example, some studies report very little IDS in non-western, small-scale societies -- including children growing up in small-scale…

Executive functions (EFs) embrace a range of cognitive control processes that allow us to control and direct our own behavior, thoughts, and emotions and to develop complex responses to difficulties. Standardized tasks commonly used to investigate EFs are reviewed. Here, a study is reported of the first challenges that children set for themselves…

The current study is the first to examine the role of exploration in play milestones development using a multi-measure micro-analytic approach. Fifteen infants, between the ages of 8 and 17 months, were observed in their natural home environment once a month for a one--hour session; their spontaneous mouthing and fingering and their play level…

A growing body of literature has established longitudinal associations between key social cognitive capacities emerging in infancy and children's subsequent theory of mind. However, existing work is limited by modest sample sizes, narrow infant measures, and theory of mind assessments with restricted variability and generalizability. The current…

What are the vocal experiences of children growing up on Malakula island, Vanuatu, where multilingualism is the norm? Long-form audio-recordings captured spontaneous speech behavior by, and around, 38 children (5-33 months, 23 girls) from 11 villages. Automated analyses revealed most children's vocal input came from female adults and other…

This study explores vocal development as an early marker of autism, focusing on canonical babbling rate and onset, typically established by 7 months. Previous reports suggested delayed or reduced canonical babbling in infants later diagnosed with autism, but the story may be complicated. We present a prospective study on 44 infants later diagnosed…

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.…

This study examined the extent to which the quality of teacher-infant interactions varies across play and routine care activities. In addition, the effects of the quantity of adult involvement in the quality of teacher-infant interactions were investigated. Participants were teachers and infants from 90 infant classrooms in Portugal. Classrooms…

Presenting pictures of faces side by side is a common paradigm to assess infants' attentional biases according to social categories, such as gender, race, and language. However, seeing static faces does not represent infants' typical experience of the social world, which involves people in motion and performing actions. Here, we assessed infants'…