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Socioemotional and referential communication are primary expressions of interpersonal engagement in infancy and beyond. Early socioemotional communication in dyadic interactions may form a foundation for triadic referential communication and gesture production, yet the role of temperament in moderating their association has not been examined. We investigated whether early socioemotional communication behaviors, and infant temperamental reactivity, were associated with later pointing production. Participants were 51 infants (45% girls) and both their parents (86.5% Dutch). Early infant socioemotional communication (production of smile, vocalizations, and gaze) was observed during separate home-based face-to-face interactions with mothers, fathers, and strangers at 4 and 8 months. At both ages, mothers and fathers reported on infant temperamental surgency and negative affectivity, and overall means were calculated. Referential communication (declarative pointing) was measured during structured lab-based observations at 12 and 15 months. Socioemotional and referential communication behaviors were microanalytically coded second by second. Poisson multilevel regression analyses indicated interaction effects between temperament and smile, vocalizations, and gazes to the adult's face with each partner in predicting pointing. High levels of infant temperamental surgency tended to enhance positive associations between early socioemotional communication behaviors with mothers and fathers and pointing. By contrast, high levels of negative affectivity tended to dampen associations between early communication behaviors with strangers and pointing. Results highlight the importance of infant socioemotional communication with diverse partners and the moderating role of temperamental reactivity in predicting referential communication. Public Significance Statement: Infant referential communication (e.g., the pointing gesture) is a foundation of early social cognition and language development, yet documented behavioral precursors of pointing are scant. This study indicates that in interaction with temperamental reactivity, early behavioral patterns of infant socioemotional communication (smile, vocalizations, gaze) with diverse partners (mother, father, stranger) predict pointing. High levels of temperamental surgency tended to enhance positive associations between early socioemotional communication behaviors with mothers and fathers and pointing, while high levels of negative affectivity dampened associations between early communication behaviors with strangers and pointing. [ABSTRACT FROM AUTHOR]

This article examines the patterns, and consequences, of infant temperamental reactivity to novel sensory input in a large (N = 357; 271 in current analysis) and diverse longitudinal sample through two approaches. First, we examined profiles of reactivity in 4-month-old infants using the traditional theory-driven analytic approach laid out by Jerome Kagan and colleagues, and derived groups characterized by extreme patterns of negative reactivity and positive reactivity. We then used a theory-neutral, data-driven approach to create latent profiles of reactivity from the same infants. Despite differences in sample characteristics and recruitment strategy, we noted similar reactivity groups relative to prior cohorts. The current data-driven approach found four profiles: high positive, high negative, high motor, and low reactive. Follow-up analyses found differential predictions of internalizing, externalizing, dysregulation, and competence trajectories across 12, 18, and 24 months of life based on 4-month reactivity profiles. Findings are discussed in light of the initial formulation of early reactivity by Kagan and the four decades of research that has followed to refine, bolster, and expand on this approach to child-centered individual differences. Public Significance Statement: This study provides insights into the patterns and consequences of infant temperamental reactivity to novel sensory input, using both theory-driven and data-driven approaches. The findings demonstrate the predictive power of infant reactivity profiles in understanding socioemotional trajectories across the first 2 years of life. These results could inform early identification and intervention efforts aimed at optimizing child well-being in diverse populations. [ABSTRACT FROM AUTHOR]

Human interpersonal capacities emerge from coordinated neural, biological, and behavioral activity unfolding within and between people. However, developmental research to date has allocated comparatively little focus to the dynamic processes of how social interactions emerge across these levels of analysis. Second-person neuroscience and dynamic systems approach together to offer an integrative framework for addressing these questions. This study quantified respiratory sinus arrhythmia and social behavior (∼360 observations per system) from 44 mothers and typically developing 9-month-old infants during a novel modified "still-face" (text message perturbation) task. Stochastic autoregression models indicate that the infant parasympathetic nervous system is coupled within and between people second by second and is sensitive to social context. Intraindividual, we found positive coupling between infants' parasympathetic nervous system activity and their social behavior in the subsequent second, but only during the moments and periods of active caregiver engagement. Between people, we found a bidirectional coregulatory feedback loop: Mothers' parasympathetic activity positively predicted that of their infant in the subsequent second, a form of synchrony that decreased during the text message perturbation and did not fully recover. Conversely, infant parasympathetic activity negatively predicted that of their mother at the subsequent second, a form of synchrony that was invariant over social context. Findings reveal unidirectional parasympathetic coupling within infants and a complementary allostatic feedback loop between mother and infant parasympathetic systems. They offer novel evidence of a dynamic, socially embedded parasympathetic system at previously undocumented timescales, contributing to both basic science and potential clinical targets to better support adaptive, multisystem social development. Public Significance Statement: This study investigated how the subconscious, "rest and digest" parasympathetic nervous system supports babies' abilities to interact with others. Results suggest that the parasympathetic system changes in real-time to help babies regulate their bodies to engage socially and that parasympathetic activity is synchronized between mothers and babies in a coregulatory fashion. Findings improve scientific knowledge and may, in the future, aid clinical efforts to support children's development. [ABSTRACT FROM AUTHOR]

Learning to descend stairs requires motor and cognitive capacities on the part of infants and opportunities for practice and assurance of safety offered by caregivers. The American Academy of Pediatrics prescribes the age strategy to teach toddlers to safely descend stairs but without much consideration for individual differences in infants' skills or caregivers' techniques. The purpose of this study was to observe the natural ways in which caregivers teach infants to descend stairs at home and the extent to which infants abide. Of particular interest was to examine the dynamic nature of caregivers' teaching and infants' learning over the session with attention to individual differences. Dyads (N = 59) were videorecorded on Zoom for 10 min interacting on stairs at home in the United States, Brazil, Canada, Italy, and Spain. Infants (n = 30 girls, 29 boys; 13-month-olds ± 1 week) were novice walkers (M = 2.04 months walking experience). Caregivers used a variety of teaching strategies and focused on "backing" and "scooting." Infants were more likely to heed caregivers' guidance when caregivers provided hands-on support and verbal encouragement suggesting infants were engaged and responsive to caregivers' overtures. Infants' walking experience predicted change in descent strategy over the session. Although infants did not show evidence of learning over the session, consistent caregiver instruction suggested caregivers were persistent, if not effective, teachers. Teaching and learning motor skills in a potentially risky task creates a unique opportunity for interaction, allowing infants and caregivers to learn from one another. Public Significance Statement: This work contributes to the general body of knowledge regarding infant motor development and problem solving in specific contexts. This study is one of the first to explore the nature of caregiver-infant interaction on stairs and identifies caregiver teaching strategies and infant motor characteristics that are associated with safe infant stair descent. By doing so, we hope to encourage further investigation of infant behavior in this context, upon which recommendations to caregivers for safe infant descent may be based. [ABSTRACT FROM AUTHOR]

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. Parents of infants aged 0-24 months (N = 278, 82.7% White, 84.5% in the United States, 46.0% of household incomes ≥ $100,000) were surveyed regarding their child's current and earliest dance behavior (movement by the child, during music, that the parent considered dance), motor development, and their own infant-directed dance. We found that dance begins early: 90% of infants produced recognizable dance by 12.8 months, and the age of onset was not solely a function of motor development. Infants who produced dance did so often, on average almost every day. We also found that dance shows qualitative developmental change over the first 2 years, rather than remaining stable. With motor development, age, and more time dancing, infants used a greater variety of movements in dance, and began to incorporate learned, imitated gestures (80% of infants by 17.9 months). 99.8% of parents reported dancing for or with their infants, raising questions about the role of infant-directed dance. These findings provide evidence that the motivation and tendency to move to music appears extremely early and that both learning and maturation lead to qualitative change in dance behavior during the first 2 years, informing broad questions about the origins of human musicality. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

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 January 31, 1992, and December 10, 2021. Parents originally reported milestone onsets in interviews and by using diaries. For each motor milestone, a linear regression model predicted the onset age using birth date. Segmented regression analyses inspected changes in slopes over time. Covariates included rural/urban housing, gestation age, season of birth, and birth weight. Infants' average crawling, cruising, and walking onset ages changed over time. After controlling for the covariates, infants' crawling onset age steadily increased until 2012, after which crawling onset age decreased. Infants' cruising onset age increased from 1991 to 2001, after which cruising onset age remained stable. After controlling for the covariates, infants' walking onset increased until 2015, after which walking onset age decreased. Thus, when infants were born explained a small but significant amount of variability in infant motor skill onset. While the current study showed that motor development changed over the years, motor development is just a model system for development more generally: Cohort effects may be pervasive across developmental domains. Using motor development as a model system for studying change suggests that generational effects due to a changing society may be pervasive across developmental domains. Public Significance Statement: From 1992 to 2021, on average infants learned to crawl, cruise, and walk at later ages. Trajectories of infant and child development are susceptible to broad social and cultural changes. Updating developmental norms to account for within-culture and cohort-level changes may be necessary. [ABSTRACT FROM AUTHOR]

Culture is a key determinant of children's development both in its own right and as a measure of generalizability of developmental phenomena. Studying the role of culture in development requires information about participants' demographic backgrounds. However, both reporting and treatment of demographic data are limited and inconsistent in child development research. A barrier to reporting demographic data in a consistent fashion is that no standardized tool currently exists to collect these data. Variation in cultural expectations, family structures, and life circumstances across communities make the creation of a unifying instrument challenging. Here, we present a framework to standardize demographic reporting for early child development (birth to 3 years of age), focusing on six core sociodemographic construct categories: biological information, gestational status, health status, community of descent, caregiving environment, and socioeconomic status. For each category, we discuss potential constructs and measurement items and provide guidance for their use and adaptation to diverse contexts. These items are stored in an open repository of context-adapted questionnaires that provide a consistent approach to obtaining and reporting demographic information so that these data can be archived and shared in a more standardized format. Public Significance Statement: The public significance of this work is to facilitate identification and diversification of samples within developmental psychology by providing a framework for capturing demographic diversity. [ABSTRACT FROM AUTHOR]

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' looking preferences for native over foreign language speakers in two social contexts: the presentation of static faces and the presentation of people performing instrumental actions. In addition, we tested infants' preferential looking at 5 and 9 months of age to assess whether their pattern of preferential looking changes across development. The results of 5-month-old infants replicated and extended previous findings by showing that, at this age, infants typically look longer at people who previously spoke their native language. As found for other social categories such as race and gender, this familiarity-based looking preference was not evident at 9 months of age when infants were presented with static faces. However, when presented with more informative dynamic events, 9-month-old infants showed a temporally aligned preference for the native over the foreign language speaker. Specifically, infants' looking preference was time-locked to the completion of the action goal: when speakers grasped and lifted a toy. These results suggest potentially a familiarity-based preference toward native language speakers around 5 months of age, which may later develop into a more strategic selective response in service of information-seeking. Public Significance Statement: This study suggests that babies are prone to look at speakers of their native language over speakers of a foreign language. At 5 months of age, this tendency may be driven by a generic preference to look at people with more familiar attributes, but at 9 months, our results suggest infants go beyond generic preference and expect that the actions of native language speakers will carry more relevant information. [ABSTRACT FROM AUTHOR]

During infancy and toddlerhood, parents show large individual differences in the extent to which they are able to tailor their parenting behaviors to their children's swiftly changing developmental needs. The first aim of our study was, therefore, to distinguish parenting profiles at three time points during infancy and toddlerhood (i.e., 5, 10, and 36 months) based on mothers' supportive presence, structure and limit-setting, and quality of instruction, as well as to examine the stability of profile structure and profile membership across time. The second aim was to examine how profile membership and profile transitions at each time point are associated with relevant parental, contextual, and child-specific factors. Data from 244 Dutch mother–child dyads were collected at three waves: when children were approximately 5 months (n = 203), 10 months (n = 181), and 3 years of age (n = 178). We found three types of parenting profiles at each wave: a competent profile, a sufficient profile, and a maladaptive profile. Only the competent parenting profile was found to have a stable structure across all three waves. In general, profile membership was least stable for the maladaptive profile. Results also showed that maternal agreeableness and a higher educational level increased the likelihood to exhibit a more competent parenting profile. Our findings advance our understanding of how parenting profiles might change due to children's swiftly changing needs and inform efforts to tailor parenting interventions to individual parents. Public Significance Statement: This study advances our understanding of which subgroups of parents exist during infancy and toddlerhood based on their parenting behaviors and how these subgroups change across time. Our findings inform efforts to tailor parenting interventions to parents of infants and toddlers. [ABSTRACT FROM AUTHOR]

Adults and children easily distinguish between fine-grained variations in trustworthiness intensity based on facial appearance, but the developmental origins of this fundamental social skill are still debated. Using a fast periodic visual stimulation (FPVS) oddball paradigm coupled with electroencephalographic (EEG) recording, we investigated neural discrimination of morphed faces that adults perceive as low- and high-trustworthy in a sample of 6-month-old infants (N = 29; 56% male; Mage = 196.8 days; all White) and young adults (N = 21; 40% male; Mage = 24.61 years; all White) recruited in Italy. Stimulus sequences were presented at 6 Hz with deviant faces interleaved every fifth stimulus (i.e., 1.2 Hz); oddball category (high/low trustworthiness) was varied within subjects. FPVS responses were analyzed at both frequencies of interest and their harmonics as a function of deviant type (high- vs. low-trustworthy) over occipital and occipitolateral electrode clusters. For both infants and adults, the baseline response did not differ between trustworthiness conditions. Significant responses were centered on the right parietal electrodes in infants, and on the occipital and left occipitotemporal clusters in adults. Oddball responses were significant for both infants and adults, with cross-age differences in the topographical localization of the response on the scalp. Overall, results suggest that, by the age of 6 months, infants discriminate between faces that adults rate as high and low in trustworthiness, extending prior evidence of early sensitivity to this face dimension in humans. Public Significance Statement: The current study provides novel evidence that the human brain discriminates between faces that adults rate as high or low in trustworthiness, suggesting that sensitive responding to facial cues associated with trustworthiness is an early emerging and foundational feature of human social competences. Additionally, it demonstrates that the fast periodic visual stimulation paradigm is an effective tool for elucidating the ontogenetic roots of this sensitivity in early infancy. [ABSTRACT FROM AUTHOR]

Process praise (i.e., praise for effort) facilitates childhood persistence. However, less is known about the mechanism by which process praise influences persistence in infancy. Here, we propose that well-timed process praise reinforces the link between effort and success, thus promoting persistence in young children. In Experiment 1, U.S. infants aged 17–18 months old (N = 29; 13 females; Mage = 18 months, 3 days; 76% White) and in Experiment 2, Canadian toddlers aged 17–31 months old (N = 60; 34 females; Mage = 22 months, 17 days; 40% White) participated with caregivers. Across experiments, caregiver process and general praise overlapping temporally with both trying and success related to greater persistence during a dyadic task, while praise offered only during trying or success was not. However, the effects of temporally aligned process praise were more robust than the effects of general praise. Furthermore, process praise which did not correspond to children's actions (i.e., high-volume or randomly dispersed process praise) negatively related to persistence. Thus, these findings demonstrate that young children are responsive to temporal alignment in praise and further suggest that temporal alignment especially in process praise may help form the basis for later mindset models. Public Significance Statement: The way caregivers talk to children helps them persist more on challenging problems. Here, we saw that when caregivers timed their praise to highlight moments when their infants' trying turned into success, infants kept trying for longer both in the laboratory and in their own homes. This timing might help infants begin to develop a positive mindset toward persistence which will be increasingly important as they grow. [ABSTRACT FROM AUTHOR]

We extend decades of research on infants' visual processing by examining their eye gaze during viewing of natural scenes. We examined the eye movements of a racially diverse group of 4- to 12-month-old infants (N = 54; 27 boys; 24 infants were White and not Hispanic, 30 infants were African American, Asian American, mixed race and/or Hispanic) as they viewed images selected from the MIT Saliency Benchmark Project. In general, across this age range infants' fixation distributions became more consistent and more adult-like, suggesting that infants' fixations in natural scenes become increasingly more systematic. Evaluation of infants' fixation patterns with saliency maps generated by different models of physical salience revealed that although over this age range there was an increase in the correlations between infants' fixations and saliency, the amount of variance accounted for by salience actually decreased. At the youngest age, the amount of variance accounted for by salience was very similar to the consistency between infants' fixations, suggesting that the systematicity in these youngest infants' fixations was explained by their attention to physically salient regions. By 12 months, in contrast, the consistency between infants was greater than the variance accounted for by salience, suggesting that the systematicity in older infants' fixations reflected more than their attention to physically salient regions. Together these results show that infants' fixations when viewing natural scenes becomes more systematic and predictable, and that predictability is due to their attention to features other than physical salience. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Infants' ability to perform visual short-term memory (VSTM) tasks develops rapidly between 6 and 8 months. Here we tested the hypothesis that infants' VSTM performance is influenced by their ability to individuate simultaneously presented objects. We used a one-shot change detection task to ask whether 6-month-old infants (N = 47) would detect a change in the color of 1 item in a 2-item array when the stimulus context facilitated individuation of the items. In Experiment 1 the 2 items in the display differed in shape and color and in Experiment 2 the onset and offset times of the 2 items differed. In both experiments, 6-month-old infants detected a change, contrasting with previous results. Thus, young infants' encoding of information about individual items in multiple-item arrays is related to their ability to individuate those items. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

We tested 6- and 8-month-old White and non-White infants (N = 53 total, 28 girls) from Northern California in a visual search task to determine whether a unique item in an otherwise homogeneous display (a singleton) attracts attention because it is a unique singleton and "pops out" in a categorical manner, or whether attention instead varies in a graded manner on the basis of quantitative differences in physical salience. Infants viewed arrays of four or six items; one item was a singleton and the other items were identical distractors (e.g., a single cookie and three identical toy cars). At both ages, infants looked to the singletons first more often, were faster to look at singletons, and looked longer at singletons. However, when a computational model was used to quantify the relative salience of the singleton in each display—which varied widely among the different singleton-distractor combinations—we found a strong, graded effect of physical salience on attention and no evidence that singleton status per se influenced attention. In addition, consistent with other research on attention in infancy, the effect of salience was stronger for 6-month-old infants than for 8-month-old infants. Taken together, these results show that attention-getting and attention-holding in infancy vary continuously with quantitative variations in physical salience rather than depending in a categorical manner on whether an item is unique. Public Significance Statement: This study shows that how infants focus their attention is influenced by several different factors, including the infants' age and the characteristics of images (such as color and brightness). These results help us understand how infants process visual information. [ABSTRACT FROM AUTHOR]

Developmental theories suggest affect-biased attention, preferential attention to emotionally salient stimuli, emerges during infancy through coordinating individual differences. Here we examined bidirectional relations between infant affect-biased attention, temperamental negative affect, and maternal anxiety symptoms using a Random Intercepts Cross-Lagged Panel model (RI-CLPM). Infant–mother pairs from Central Pennsylvania and Northern New Jersey (N = 342; 52% White; 50% reported as assigned female at birth) participated when infants were 4, 8, 12, 18 and 24 months of age. Infants completed the overlap task while eye-tracking data were collected. Mothers reported their infant's negative affect and their own anxiety symptoms. In an RI-CLPM, after accounting for between-person variance (random intercepts representing the latent average of a construct), it is possible to assess within-person variance (individual deviations from the latent average of a construct). Positive relations represent stability in constructs (smaller within-person deviations). Negative relations represent fluctuation in constructs (larger within-person deviations). At the between-person level (random intercepts), mothers with greater anxiety symptoms had infants with greater affect-biased attention. However, at the within-person level (deviations), greater fluctuation in maternal anxiety symptoms at 12- and 18 months prospectively related to greater stability in attention to angry facial configurations. Additionally, greater fluctuation in maternal anxiety symptoms at 18 months prospectively related to greater stability in attention to happy facial configurations. Finally, greater fluctuation in maternal anxiety symptoms at 4- and 12 months prospectively related to greater stability in infant negative affect. These results suggest that environmental uncertainty, linked to fluctuating maternal anxiety, may shape early socioemotional development. Public Significance Statement: The current study capitalizes on a multisite, longitudinal data set to assess individual differences associated with affect-biased attention development and early anxiety risk. We found that although overall mothers with higher levels of anxiety symptoms have infants that exhibit greater affect-biased attention, over time, infants with mothers who fluctuate more in maternal anxiety symptoms exhibit more stable affect-biased attention. Environmental uncertainty, linked to fluctuating maternal anxiety, may shape early socioemotional development. [ABSTRACT FROM AUTHOR]

Can well-documented gender differences in evaluations of prosocial versus antisocial actions found in childhood and adulthood be traced to sex differences in basic sociomoral preferences in infancy? We provide an answer to this question by meta-analyzing sex differences in preference for prosocial over antisocial agents in a set of 53 samples of American and European infants and toddlers aged between 4 and 32 months (N = 1,094). Although the original studies were agnostic to sex differences, we were able to retrieve the original data sets and estimate the effect of infants' and toddlers' sex on sociomoral preferences. Employing both a standard frequentist and a Bayesian approach to meta-analysis, we found strong evidence supporting the absence of sex differences in sociomoral preferences among infants and toddlers. We discuss the relevance of this finding for theories and descriptions of the emergence and developmental trajectory of gender differences in morality. Public Significance Statement: We found strong evidence that, within the first 3 years of life, males and females do not differ in their tendency to prefer prosocial agents over antisocial agents, a tendency that is considered by many to be a building block of adult moral cognition. The present meta-analysis gives evidence to evaluate theories and hypotheses about the development of gender differences in moral judgment. [ABSTRACT FROM AUTHOR]

This study examined the development of caregiver mind-mindedness—defined as the propensity to see one's child as an agent with an independent mind—across the first 1,000 days of life. At four time-points (i.e., third trimester of pregnancy, 4, 14, and 24 months postpartum), 384 first-time mothers (Mage = 32.55, SD = 3.63 years) and fathers (Mage = 33.96, SD = 4.40 years) gave 5-minute speech samples about their infant that were coded for mind-mindedness (Meins & Fernyhough, 2015). Reflecting the local population, the 192 heterosexual couples were highly educated (84.6% of mothers, 77.1% of fathers had a degree) and ethnically homogenous (92.7% of mothers, 94.8% of fathers identified as White British). Results showed significant variability in mind mindedness within both expectant mothers and expectant fathers, with no mean group difference. Auto-regressive models demonstrated modest positive associations between prenatal and postnatal mind-mindedness. Latent change score models showed gains in mean mind-mindedness over time that, on average, were stronger for mothers than for fathers. For fathers, gains in mind-mindedness were positively associated with having an infant daughter and infant surgency. For mothers, higher socioeconomic status and more equal childcare were associated with greater gains in mind-mindedness across toddlerhood. Within-couple associations were evident for changes in mind-mindedness, but not for initial (prenatal) scores. We apply the relational account of mind-mindedness to frame our discussion of these findings that, by highlighting both developmental stability and change in mind-mindedness, suggest fruitful avenues for future research. Public Significance Statement: Parental mind-mindedness—defined as the propensity to see one's child as an agent with an independent mind—has established links with children's social, emotional, cognitive, and behavioral outcomes. Understanding the developmental origins and changes in parental mind-mindedness is important for both theory and practice. In this study of 384 low-risk first-time mothers and fathers, 5-minute speech samples were used to code mind-mindedness at four time points (in the third trimester of pregnancy and at 4, 14, and 24 months postpartum). For both mothers and fathers, individual differences in mind-mindedness were: (a) measurable during pregnancy; and (b) modestly stable across these four time-points. Across the transition to parenthood and the first 2 years of life, parents showed significant gains in mind-mindedness that were (a) similar within couples and associated with (b) having an infant daughter and temperamentally emotionally reactive infant for fathers and (c) equal childcare and higher socioeconomic status for mothers. [ABSTRACT FROM AUTHOR]

The faces and hands of caregivers and other social partners offer a rich source of social and causal information that is likely critical for infants' cognitive and linguistic development. Previous work using manual annotation strategies and cross-sectional data has found systematic changes in the proportion of faces and hands in the egocentric perspective of young infants. Here, we validated the use of a modern convolutional neural network (OpenPose) for the detection of faces and hands in naturalistic egocentric videos. We then applied this model to a longitudinal collection of more than 1.700 head-mounted camera videos from three children ages 6 to 32 months. Using these detections, we confirm and extend prior results from cross-sectional studies. First. we found a moderate decrease in the proportion of faces in children's view across age and a higher proportion of hands in view than previously reported. Second. we found variability in the proportion of faces and hands viewed by different children in different locations (e.g., living room vs. kitchen). suggesting that individual activity contexts may shape the social information that infants experience. Third, we found evidence that children may see closer, larger views of people. hands. and faces earlier in development. These longitudinal analyses provide an additional perspective on the changes in the social information in view across the first few years of life and suggest that pose detection models can successfully be applied to naturalistic egocentric video data sets to extract descriptives about infants' changing social environment. [ABSTRACT FROM AUTHOR]

The ability to map similar sounding words to different meanings alone is far from enough for successful speech processing. To overcome variability in the speech signal, young learners must also recognize words across surface variations. Previous studies have shown that infants at 14 months are able to use variations in word-internal cues (i.e., acoustic cues within the target word) to form phonological categories and to learn words. The present study takes into consideration the fact that talker variability can easily lead to acoustic overlap between phonological categories, in which case reliance on word-external cues (i.e., acoustic cues in the context preceding and/or following the target word, also referred to as contextual cues) as a frame of reference is obligatory for successful talker adaptation. In a series of experiments, the present study examines when infants are able to use word-external cues to tune to different talkers for the benefit of word learning. Cantonese-learning 14-month-old, 18-month-old, and 24-month-old infants (N = 258) were tested on the associative learning of Cantonese Tone 1-Tone 3 contrast. Results showed that talker variability that yielded acoustic overlap between the two tonal categories compromised infants' ability to map the contrast onto word meanings. However, when given speaker-matched contextual cues, infants as young as 14 months of age demonstrated a certain degree of talker adaptation which may have subserved their use of phonetic details in novel word learning. [ABSTRACT FROM AUTHOR]

Four experiments examined how faces compete with physically salient stimuli for the control of attention in 4-, 6-, and 8-month-old infants (N = 117 total). Three computational models were used to quantify physical salience. We presented infants with visual search arrays containing a face and familiar object(s), such as shoes and flowers. Six- and 8-month-old infants looked first and longest at faces; their looking was not strongly influenced by physical salience. In contrast, 4-month-old infants showed a visual preference for the face only when the arrays contained 2 items and the competitor was relatively low in salience. When the arrays contained many items or the only competitor was relatively high in salience, 4-month-old infants' looks were more often directed at the most salient item. Thus, over ages of 4 to 8 months, physical salience has a decreasing influence and faces have an increasing influence on where and how long infants look.

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 socialemotional (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 participating families (N = 143) were ethnically homogenous ( 88% Caucasian) but economically diverse (31% low-to-very-low income). Mothers reported on their children's SoE outcomes including externalizing, internalizing, dysregulating problem behaviors as well as SoE competence when infants (54% girls) were 12, 18. and 24 months old. At each age point, HC was assessed through observations during home visits and compliance to the study protocols. Multilevel modeling revealed increasing developmental trajectories in all of the domains of SoE outcomes across the second year of life, reflecting the premise that these behavioral systems continue to form and become increasingly part of the infant's behavioral repertoire as development unfolds. However. compared to infants in less chaotic homes, infants in more chaotic households experienced steeper increases in both externalizing and internalizing problem behaviors across the second year, and girls showed higher levels of internalizing problem behaviors compared to boys. Results emphasize the increasing trajectories of problem behaviors in relation to ongoing chaotic caregiving environment among infants as young as 2 years of age. [ABSTRACT FROM AUTHOR]

Over the last 2 centuries there has been a rapid increase in the proportion of children who grow up in cities. However, relatively little work has explored in detail the physiological and cognitive pathways through which city life may affect early development. To assess this, we observed a cohort of infants growing up in diverse settings across South East England across a 2-day assessment battery. On Visit 1, day-long home recordings were made to monitor infants' physiological stress in real-world settings. On Visit 2, lab batteries were administered to measure infants' cognitive, emotional, and neural reactivity. Infants from more high-density urban environments showed increased physiological stress (decreased parasympathetic nervous system activity) at home. This relationship was independent of socioeconomic status and lifelong stressors. Behaviorally, infants raised in high-density settings showed lower sustained attention in the lab, along with increased behavioral and physiological reactivity during an emotion elicitation task. However, they also showed increased recognition memory for briefly presented stimuli and increased neural engagement with novel stimuli. This pattern is consistent with other research into how elevated physiological stress influences cognition, and with theoretical approaches from adult research that predict that city life is associated with a profile of cognitive strengths as well as weaknesses. Implications for education and developmental psychopathology are discussed. [ABSTRACT FROM AUTHOR]

We extend decades of research on infants' visual processing by examining their eye gaze during viewing of natural scenes. We examined the eye movements of a racially diverse group of 4- to 12-month-old infants (N = 54; 27 boys; 24 infants were White and not Hispanic, 30 infants were African American, Asian American, mixed race and/or Hispanic) as they viewed images selected from the MIT Saliency Benchmark Project. In general, across this age range infants' fixation distributions became more consistent and more adult-like, suggesting that infants' fixations in natural scenes become increasingly more systematic. Evaluation of infants' fixation patterns with saliency maps generated by different models of physical salience revealed that although over this age range there was an increase in the correlations between infants' fixations and saliency, the amount of variance accounted for by salience actually decreased. At the youngest age, the amount of variance accounted for by salience was very similar to the consistency between infants' fixations, suggesting that the systematicity in these youngest infants' fixations was explained by their attention to physically salient regions. By 12 months, in contrast, the consistency between infants was greater than the variance accounted for by salience, suggesting that the systematicity in older infants' fixations reftected more than their attention to physically salient regions. Together these results show that infants' fixations when viewing natural scenes becomes more systematic and predictable, and that predictability is due to their attention to features other than physical salience. [ABSTRACT FROM AUTHOR]

Infants avoid touching plants. Here we examine for the first time whether infants are also reluctant to touch plant foods. We hypothesized that infants would avoid plant foods because food neophobia-the avoidance of novel foods-is particularly strong for fruits and vegetables. However, we predicted that infants would avoid processed plant foods to a lesser degree than whole leafy plants because they bear the markers of previous human engagement. In a first assessment, we presented 7- to 15-month-old infants, recruited from a predominantly White population around Berlin, Germany (N = 56; 29 girls), with whole plants, processed whole plant foods, and nonplant food controls. We measured infants' latency to touch each object and their social looks toward adults prior to the first touch. In a follow-up assessment I year later, participants' caregivers filled out a questionnaire measuring their child's food neophobia. Infants avoided touching both whole plants and processed plant foods, and engaged in more social looking before touching them, relative to their matched controls. However, infants took longer to touch and engaged in more social looking for whole plants than processed plant foods. The follow-up assessment indicated that avoidance of cut plant foods in older infants was related to their food neophobia measured 1 year later. These results demonstrate that (a) infants avoid plant foods, (b) cues of food processing decrease infants' reluctance to touch plant foods relative to unprocessed plants, suggesting that these cues may signal food safety, and (c) avoiding certain types of plant foods in infancy may be a precursor of later food neophobia. [ABSTRACT FROM AUTHOR]

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 vs. hat). This meta-analysis focuses on studies investigating infants' ability to detect mispronunciations in familiar words. or mispronunciation sensitivity, Our goal was to evaluate the development of infants' phonological representations for familiar words as well as explore the role of experimental manipulations related to theoretical questions and of analysis choices. The results show that although infants are sensitive to mispronunciations, they still accept these altered forms as labels for target objects. Interestingly, this ability is not modulated by age or vocabulary size, suggesting that a mature understanding of native language phonology may be present in infants from an early age. possibly before the vocabulary explosion. These results support several theoretical assumptions made in the literature, such as sensitivity to mispronunciation size and position of the mispronunciation. We also shed light on the impact of data analysis choices that may lead to different conclusions regarding the development of infants' mispronunciation sensitivity. Our article concludes with recommendations for improved practice in testing infants' word and sentence processing online. [ABSTRACT FROM AUTHOR]

To benefit from the exploration of their bodies and their physical and social environments, infants need to detect sensorimotor contingencies linking their actions to sensory feedback. This ability, which seems to be present in babies from birth and even in utero, has been widely used by researchers in their study of early development. However, a careful review of the literature, particularly the recent literature, suggests that babies may not be uniformly sensitive to all sensorimotor contingencies. This literature review examines in detail sensorimotor contingency detection in infants before the age of 1 year. Four aspects of sensorimotor contingency detection are considered: characteristics of action and feedback, contingency parameters, exposure conditions, and interindividual differences. For each topic, we highlight what favors and what hinders the detection of sensorimotor contingencies in infants. Our review also demonstrates the limitations of our knowledge about sensorimotor contingency detection. We emphasize the importance of making progress in this field at a time when sensorimotor contingency detection is of major interest in developmental robotics and artificial intelligence. [ABSTRACT FROM AUTHOR]

Accurate perception of emotional (facial) expressions is an essential social skill. It is currently debated whether emotion categorization in infancy emerges in a "broad-to-narrow" pattern and the degree to which language influences this process. We used an habituation paradigm to explore (a) whether 14- and 18-month-old infants perceive different facial expressions (anger, sad, disgust) as belonging to a superordinate category of negative valence and (b) how verbal labels influence emotion category formation. Results indicated that infants did not spontaneously form a superordinate category of negative valence (Experiments 1 and 3). However, when a novel label ("toma") was added to each event during habituation trials (Experiments 2 and 4), infants formed this superordinate valance category when habituated to disgust and sad expressions (but not when habituated to anger and sadness). These labeling effects were obtained with two stimuli sets (Radboud Face Database and NimStim), even when controlling for the presence of teeth in the expressions. The results indicate that infants, at 14 and 18 months of age, show limited superordinate categorization based on the valence of different negative facial expressions. Specifically, infants only form this abstract emotion category when labels were provided, and the labeling effect depends on which emotions are presented during habituation. These findings have important implications for developmental theories of emotion. [ABSTRACT FROM AUTHOR]

The Socialization of Emotion (Eisenberg, Cumberland, & Spinrad, 1998; Eisenberg, Spinrad, & Cumberland, 1998) model creates a theoretical framework for understanding parents' direct and indirect influences on children's emotional development, including the influence of parent characteristics on subsequent emotion specific parenting. Large numbers of children live in families with fathers who have alcohol problems, setting the stage for cascading risk across development. For instance, fathers' alcohol problems are a marker of risk for higher family conflict, increased parental depression and antisociality, and less sensitive parenting, leading to dysregulated child emotion and behavior. We examined a conceptual model for emotion socialization in a community sample of alcoholic and nonalcoholic father families (N = 227) recruited in infancy (i.e., 12 months) with follow-ups to adolescence (i.e., 15–19 years), and examined if hypothesized paths differed by child sex or group status (alcoholic vs. nonalcoholic families). Results indicated significant indirect effects between parent psychopathology and sensitivity in early childhood to both adaptive (e.g., emotion regulation) and maladaptive (e.g., aggression and peer delinquency) outcomes in middle childhood to adolescence via child negative emotionality and supportive emotion socialization. There were significant differences by child sex and alcohol group status. Implications for intervention and prevention are discussed. [ABSTRACT FROM AUTHOR]

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 understanding of dyadic coordination by investigating how different measures of coordination relate to one another and how individual behaviors relate to dyadic coordination within the vocal and gaze domains. Thirty dyads were recorded playing together with a standard set of toys when infants were 3, 6, 9, and 12 months of age, and mother and infant vocalization and gaze behaviors were coded from these videos on a moment-to-moment basis. Coordination was analyzed using both cross-recurrence quantitative analysis and event-based measures of analysis. Hierarchical linear modeling was used to examine developmental trajectories of vocalization and gaze coordination. Results indicated that dyadic coordination of the timing of vocalization and gaze behaviors is a very early emerging phenomenon that is supported by both mothers and infants. Vocal coordination did not show developmental change over time, whereas mothers and infants became increasingly coordinated in their gaze behaviors as infants got older. Taken together, findings from this study highlight the importance of considering bidirectional and developmental influences on parent and infant behavior. [ABSTRACT FROM AUTHOR]

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 setup of a top-open container 90 degrees such that the opening now faced the side. An object was held vertically aligned with the side opening, enhancing the direct comparison of height. After the object was glided behind or inside the container and became hidden, 5-month-olds detected a height change in both containment and occlusion events. Thus, enhanced support for comparison facilitated young infants' use of key information in physical events (i.e., height in containment events). The finding underscores the importance of considering the role of comparison in the research of intuitive physics in infancy. [ABSTRACT FROM AUTHOR]

A talking face provides redundant cues on the mouth that might support language learning and highly salient social cues in the eyes. What drives children's looking toward the mouth versus eyes of a talking face? This study reports data from 292 children who viewed faces speaking English, French, and Russian. We investigated the impact of children's age (5 months to 5 years) and language background (monolingual English, monolingual French, bilingual English-French), and the speaker's language (dominant, nondominant, or nonnative) relative to children's native language(s). Data from 129 bilingual adults were also collected for comparison. Five-month-olds showed balanced attention to the eyes and mouth, but children up to 5 years tended to be most interested in the mouth. In contrast, adults were most interested in the eyes. We found little evidence for different patterns of attention for monolinguals versus bilinguals, or to a native versus a nonnative speaker. Using percentile scores, monolinguals with larger productive vocabularies looked more at the mouth, while bilinguals with larger comprehension vocabularies looked marginally less at the mouth, although both effects were small and not as robust with raw vocabulary scores. Children showed large but stable individual variability in their face scanning patterns across different speakers. Our results show that the way that children allocate their attention to talking faces continues to change from infancy through the preschool years and beyond. Future studies will need to go beyond looking at bilingualism, speaker language, and vocabulary size to understand what drives children's in-the-moment attention to talking faces. [ABSTRACT FROM AUTHOR]

Around their first birthdays, infants begin to point, walk, and talk. These abilities are appreciable both by researchers with strictly standardized criteria and caregivers with more relaxed notions of what each of these skills entails. Here, we compare the onsets of these skills and links among them across two data collection methods: observation and parental report. We examine pointing, walking, and talking in a sample of 44 infants studied longitudinally from 6 to 18 months. In this sample, links between pointing and vocabulary were tighter than those between walking and vocabulary, supporting a unified socio-communicative growth account. Indeed, across several cross-sectional and longitudinal analyses, pointers had larger vocabularies than their nonpointing peers. In contrast to previous work, this did not hold for walkers' versus crawlers' vocabularies in our sample. Comparing across data sources, we find that reported and observed estimates of the growing vocabulary and of age of walk onset were closely correlated, while agreement between parents and researchers on pointing onset and talking onset was weaker. Taken together, these results support a developmental account in which gesture and language are intertwined aspects of early communication and symbolic thinking, whereas the shift from crawling to walking appears indistinct from age in its relation with language. We conclude that pointing, walking, and talking are on similar timelines yet distinct from one another, and discuss methodological and theoretical implications in the context of early development. [ABSTRACT FROM AUTHOR]

Face scanning is an important skill that takes place in a highly interactive context embedded within social interaction. However, previous research has studied face scanning using noninteractive stimuli. We aimed to study face scanning and social interaction in infancy in a more ecologically valid way by providing infants with a naturalistic and socially engaging experience. We developed a novel gaze- contingent eye-tracking paradigm in which infants could interact with face stimuli. Responses (socially engaging/socially disengaging) from faces were contingent on infants' eye movements. We collected eye-tracking and behavioral data of 162 (79 male, 83 female) 6-, 9- and 12-month-old infants. All infants showed a clear preference for looking at the eyes relative to the mouth. Contingency was learned implicitly, and infants were more likely to show behavioral responses (e.g., smiling, pointing) when receiving socially engaging responses. Infants' responses were also more often congruent with the actors' responses. Additionally, our large sample allowed us to look at the ranges of behavior on our task, and we identified a small number of infants who displayed deviant behaviors. We discuss these findings in relation to data collected from a small sample (N = 11) of infants considered to be at-risk for autism spectrum disorders. Our results demonstrate the versatility of the gaze-contingency eye-tracking para- digm, allowing for a more nuanced and complex investigation of face scanning as it happens in real-life interaction. As we provide additional measures of contingency learning and reciprocity, our task holds the potential to investigate atypical neurodevelopment within the first year of life. [ABSTRACT FROM AUTHOR]

Associative word learning, the ability to pair a concept to a word, is an essential mechanism for early language development. One common method by which researchers measure this ability is the Switch task (Werker, Cohen, Lloyd, Casasola, & Stager, 1998), wherein infants are habituated to 2 word-object pairings and then tested on their ability to notice a switch in those pairings. In this comprehensive meta-analysis, we summarized 141 Switch task studies involving 2,723 infants of 12 to 20 months to estimate an average effect size for the task (random-effect model) and to explore how key experimental factors affect infants' performance (fixed-effect model). The average effect size was low to moderate in size, Cohen's d = 0.32. The use of language-typical and dissimilarsounding words as well as the presence of additional facilitative cues aided performance, particularly for younger infants. Infants learning 2 languages at home outperformed those learning 1, indicating a bilingual advantage in learning word-object associations. Together, these findings support the Processing Rich Information from Multidimensional Interactive Representations (PRIMIR) theoretical framework of infant speech perception and word learning (e.g., Werker & Curtin, 2005), but invite further theoretical work to account for the observed bilingual advantage. Lastly, some of our analyses raised the possibility of questionable research practices in this literature. Therefore, we conclude with suggestions (e.g., preregistration, transparent data peeking, and alternate statistical approaches) for how to address this important issue. [ABSTRACT FROM AUTHOR]

Adult humans process communicative interactions by recognizing that information is being communicated through speech (linguistic ability) and simultaneously evaluating how to respond appropriately (social-pragmatic ability). These abilities may originate in infancy. Infants understand how speech communicates in social interactions, helping them learn language and how to interact with others. Infants later diagnosed with autism spectrum disorder (ASD), who show deficits in social-pragmatic abilities, differ in how they attend to the linguistic and social-pragmatic information in their environment. Despite their interdependence, experimental measures of language and social-pragmatic attention are often studied in isolation in infancy. Thus, the extent to which language and social-pragmatic abilities are related constructs remains unknown. Understanding how related or separable language and socialpragmatic abilities are in infancy may reveal whether these abilities are supported by distinguishable developmental mechanisms. This study uses a single communicative scene to examine whether real-time linguistic and social-pragmatic attention are separable in neurotypical infants and infants later diagnosed with ASD, and whether attending to linguistic and social-pragmatic information separately predicts later language and social-pragmatic abilities 1 year later. For neurotypical 12-month-olds and 12-month-olds later diagnosed with ASD, linguistic attention was not correlated with concurrent social-pragmatic attention. Furthermore, infants' real-time attention to the linguistic and social-pragmatic aspects of the scene at 12 months predicted and distinguished language and social-pragmatic abilities at 24 months. Language and social-pragmatic attention during communication are thus separable in infancy and may follow distinguishable developmental trajectories. [ABSTRACT FROM AUTHOR]

Over the past decade, numerous studies have reported that infants prefer prosocial agents (those who provide help, comfort, or fairness in distributive actions) to antisocial agents (those who harm others or distribute goods unfairly). We meta-analyzed the results of published and unpublished studies on infants aged 4-32 months and estimated that approximately two infants out of three, when given a choice between a prosocial and an antisocial agent, choose the former. This preference was not significantly affected by age or other factors, such as the type of dependent variable (selective reaching or helping) or the modality of stimulus presentation (cartoons or real events). Effect size was affected by the type of familiarization events: giving/taking actions increased its magnitude compared with helping/hindering actions. There was evidence of a publication bias, suggesting that the effect size in published studies is likely to be inflated. Also, the distribution of children who chose the prosocial agent in experiments with N = 16 suggested a file-drawer problem. [ABSTRACT FROM AUTHOR]

Correct counting respects the stable order principle whereby the count terms are recited in a fixed order every time. The 4 experiments reported here tested whether precounting infants recognize and prefer correct stable-ordered counting. The authors introduced a novel preference paradigm in which infants could freely press two buttons to activate videos of counting events. In the "correct" counting video, number words were always recited in the canonical order ("1, 2, 3, 4, 5, 6"). The "incorrect" counting video was identical except that the number words were recited in a random order (e.g., "5, 3, 1,6, 4, 2"). In Experiment 1, 18-month-olds (n = 21), but not 15-month-olds (n = 24), significantly preferred to press the button that activated correct counting events. Experiment 2 revealed that English-leaming 18-month-olds' (n = 21) preference for stable-ordered counting disappeared when the counting was done in Japanese. By contrast, Experiment 3 showed that multilingual 18-month-olds (n = 24) preferred correct stable-ordered counting in an unfamiliar foreign language. In Experiment 4, multilingual 18- month-olds (N = 21) showed no preference for stable-ordered alphabet sequences, ruling out some alternative explanations for the Experiment 3 results. Overall these findings are consistent with the idea that implicit recognition of the stable order principle of counting is acquired by 18 months of age, and that learning more than one language may accelerate infants' understanding of abstract counting principles. [ABSTRACT FROM AUTHOR]

Fragmented sleep is common in infancy. Although night awakening is known to decrease with age, in some infants night awakening is more persistent and continues into older ages. However, the influence of fragmented sleep on development is poorly known. In the present study, the longitudinal relationship between fragmented sleep and psychomotor development (Bayley Scales of Infant and Toddler Development [Bayley-III]; Bayley, 2009) was investigated in infants with (≤ 3 night awakenings, n = 81) and without fragmented sleep ( s i night awakening, n = 70) within the CHILD-SLEEP birth cohort at 8 and 24 months of age. Differences in parent-reported (Brief Infant Sleep Questionnaire [BISQ]) sleep parameters were studied at 8,18, and 24 months of age. Group differences in night awakening were stable across all assessment points. Infants with fragmented sleep slept less in total than infants without fragmented sleep and they did not compensate their nocturnal sleep during daytime. Additionally, infants with fragmented sleep spent more time awake at night than infants without fragmented sleep. However, psychomotor development did not differ between infants with and without fragmented sleep at 8 or 24 months of age. Our findings indicate that early onset fragmented sleep did not have a negative effect on psychomotor development within the first 2 years despite the differences in sleep length among infants with and without fragmented sleep. In the future, more specific domains of cognitive development and various factors affecting sleep fragmentation should be taken into account when studying the developmental effects of night awakening in infancy. [ABSTRACT FROM AUTHOR]

Infants exhibit visual preferences for gender-typed objects (e.g., dolls, toy vehicles) that parallel the gender-typed play preferences of preschool-aged children, but the developmental stability of individual differences in early emerging gender-typed preferences has not yet been characterized. In the present study, we examined the longitudinal association between infants' (N = 51) performance on an objectpreference task, administered between 6 and 13 months of age, and their play preferences at 4 years of age. Greater visual interest in a toy truck relative to a doll in infancy predicted significantly greater male-typical toy and activity preferences (e.g., play with vehicles, videogames) at age 4. These findings suggest that gender-typed object preferences present during the 1st year of life may represent the developmental precursors of gender-typed play preferences observed later in childhood. [ABSTRACT FROM AUTHOR]

In the present investigation, we studied the development of 6 physically aggressive behaviors in infancy and toddlerhood, posing 3 questions (a) How do the prevalences of individual physically aggressive behaviors change from 8, 15, and 24 months? (b) Are there groups of children who show distinctive patterns in the way individual physically aggressive behaviors develop over time? (c) What are the behavioral pathways leading from 8- to 24-month acts of physical aggression? Mothers and fathers (N = 272) from a moderately at-risk population reported on their children's physical aggression at each time point. The results revealed the commonality of physical aggression at all ages studied and the diverging developmental patterns of individual behaviors. Some physically aggressive behaviors became less common (e.g., hair pulling), while others became more common (e.g., hitting), with age. Roughly 42% of the children exhibited an increased propensity, relative to their peers, to aggress at all ages. Kicking, biting, hair pulling, and pinching/scratching at 8 months were the first steps on behavioral pathways leading to physical aggression at 24 months. These pathways principally suggested heterotypic continuity in physical aggression. [ABSTRACT FROM AUTHOR]

Whereas some evidence suggests that toddlers consider targets' deservingness when deciding whom to help, other research demonstrates that toddlers help indiscriminately. The present findings shed light on this discrepancy by demonstrating that although toddlers do exhibit selectivity in giving behaviors, their emotional responses are comparatively indiscriminate. Specifically, in Experiment 1, 20-month-olds (N = 64) were more likely to give preferred toys to prosocial versus antisocial puppets, and more likely to withhold toys from antisocial versus prosocial puppets. Experiment 2 (N = 64) ruled out low-level explanations for the effects observed in Experiment I, demonstrating that toddlers do not show the same effects when puppets' toy preferences are unclear. Despite providing evidence for selectivity in giving behaviors, across both experiments, toddlers were happier after giving than before giving, regardless of what they gave or whom they gave to. These results reveal the possibility of a divergence in early prosociality: Toddlers' giving behaviors are responsive to recipient deservingness, but their after-the-fact emotional reactions are responsive to giving acts themselves. Results are discussed in terms of their relevance to the debate regarding whether toddlers' early prosocial behaviors are discriminate versus indiscriminate. [ABSTRACT FROM AUTHOR]

The current study examined the relations between individual differences in attention to emotion faces and temperamental negative affect across the first 2 years of life. Infant studies have noted a normative pattern of preferential attention to salient cues, particularly angry faces. A parallel literature suggests that elevated attention bias to threat is associated with anxiety, particularly if coupled with temperamental risk. Examining the emerging relations between attention to threat and temperamental negative affect may help distinguish normative from at-risk patterns of attention. Infants (N = 145) ages 4 to 24 months (M = 12.93 months, SD = 5.57) completed an eye-tracking task modeled on the attention bias "dot-probe" task used with older children and adults. With age, infants spent greater time attending to emotion faces, particularly threat faces. All infants displayed slower latencies to fixate to incongruent versus congruent probes. Neither relation was moderated by temperament. Trial-by-trial analyses found that dwell time to the face was associated with latency to orient to subsequent probes, moderated by the infant's age and temperament. In young infants low in negative affect longer processing of angry faces was associated with faster subsequent fixation to probes; young infants high in negative affect displayed the opposite pattern at trend. Findings suggest that although age was directly associated with an emerging bias to threat, the impact of processing threat on subsequent orienting was associated with age and temperament. Early patterns of attention may shape how children respond to their environments, potentially via attention's gate-keeping role in framing a child's social world for processing. [ABSTRACT FROM AUTHOR]

This research examined whether infants tested longitudinally at 10, 14, and 16 months of age (N = 58) showed evidence of perceptual narrowing based on face gender (better discrimination of female than male faces) and whether changes in caregiving experience longitudinally predicted changes in infants' discrimination of male faces. To test face discrimination, infants participated in familiarization/novelty preference tasks and visual search tasks including female and male faces. At each age of participation, they were coded as having a female primary caregiver only or distributed caregiving experience (alternating experience with a female and male primary caregiver). Perceptual narrowing was evident for infants with a female primary caregiver, but only within the visual search task, which required location of a familiarized face among 3 novel distractor faces (exemplar-based discrimination); it was not evident within the familiarity/novelty preference task, which required discrimination between a familiarized and novel face (individual-based discrimination). Caregiving experience significantly explained individual changes in infants' ability to locate male faces during the visual search task after 10 months. These data are the first to demonstrate flexibility of the face processing system in relation to gender discrimination when there is a change in caregiver within the infants' natural environment after perceptual narrowing normally manifests. [ABSTRACT FROM AUTHOR]

Previous research has suggested that early development may be an optimal period to implement cognitive training interventions, particularly those relating to attention control, a basic ability that is essential for the development of other cognitive skills. In the present study, we administered gaze-contingent training (95 min across 2 weeks) targeted at voluntary attention control to a cohort of typical 12-month-old children (N = 24) and sham training to a control group (N = 24). We assessed training effects on (a) tasks involving nontrained aspects of attention control: visual sustained attention, habituation speed, visual recognition memory, sequence learning, and reversal learning; (b) general attentiveness (on-task behaviors during testing); and (c) salivary cortisol levels. Assessments were administered immediately after the cessation of training and at a 6-week follow-up. On the immediate posttest infants showed significantly more sustained visual attention, faster habituation, and improved sequence learning. Significant effects were also found for increased general attentiveness and decreased salivary cortisol. Some of these effects were still evident at the 6-week follow-up (significantly improved sequence learning and marginally improved sustained attention). These findings extend the emerging literature showing that attention training is possible in infancy. [ABSTRACT FROM AUTHOR]

Infants become increasingly helpful during the second year. We investigated experimentally whether adults' explicit scaffolding influences this development. Infants (N = 69, 13-18 months old) participated in a series of simple helping tasks. Half of infants received explicit scaffolding (encouragement and praise), whereas the other half did not. Among younger infants (below 15 months), infants who received explicit scaffolding helped twice as often as infants in the control group, and also helped more on several subsequent trials when no scaffolding was provided. As predicted, older infants were not affected by explicit scaffolding. These results demonstrate the influence of social experiences in early helping, but also how the effects of scaffolding may depend on the developmental level of the child. Less explicit forms of scaffolding may be effective when children are older. [ABSTRACT FROM AUTHOR]

We apply a biopsychosocial conceptualization to attention development in the 1st year and examine the role of neurophysiological and social processes on the development of early attention processes. We tested whether maternal behavior measured during 2 mother--child interaction tasks when infants (N = 388) were 5 months predicted infant medial frontal (F3/F4) EEG power and observed attention behavior during an attention task at 10 months. After controlling for infant attention behavior and EEG power in the same task measured at an earlier 5-month time point, results indicated a significant direct and positive association from 5-month maternal positive affect to infant attention behavior at 10 months. However, maternal positive affect was not related to medial frontal EEG power. In contrast, 5-month maternal intrusive behavior was associated with infants' task-related EEG power change at the left frontal location, F3, at 10 months of age. The test of indirect effects from 5-month maternal intrusiveness to 10-month infant attention behavior via infants' EEG power change at F3 was significant. These findings suggest that the development of neural networks serving attention processes may be 1 mechanism through which early maternal behavior is related to infant attention development in the 1st year and that intrusive maternal behavior may have a particularly disruptive effect on this process. [ABSTRACT FROM AUTHOR]

An ability to perceive tactile and visual stimuli in a common spatial frame of reference is a crucial ingredient in forming a representation of one's own body and the interface between bodily and external space. In this study, the authors investigated young infants' abilities to perceive colocation between tactile and visual stimuli presented on the hands. They examined infants' visual preferences for spatially congruent and incongruent visual-tactile events across two age groups (6 months and 10-months). They observed increased duration of looking to incongruent stimuli displays in both age groups, indicating that infants from at least 6 months of age demonstrate the ability to determine whether simultaneously presented visual-tactile perceptual events are colocated or not. These findings indicate that an ability to perceive visual and tactile stimuli within a common spatial frame of reference is available by the end of the first half year of life. [ABSTRACT FROM AUTHOR]

Given the centrality of prosociality in everyday social functioning, understanding the factors and mechanisms underlying the origins of prosocial development is of critical importance. This experiment investigated whether experience with reciprocal object exchanges can drive the developmental onset of sharing behavior. Seven-month-old infants took part in 2 laboratory visits to assess their sharing behavior and ability to release objects. During the intervening 7- to 14-day period parents led infants in an intervention in which they were either encouraged to release objects into a container (bucket condition, n = 20), or share objects with the parent in the context of reciprocal object exchanges (sharing condition, n = 20). Results showed that infants in the sharing condition shared significantly more than infants in the bucket condition following the intervention, and infants in the sharing condition significantly increased their sharing behavior across the 2 visits. Parental empathy moderated the effect of this sharing intervention, but frequency of practice did not. These results suggest that reciprocal turn-taking in dyadic object-exchange interactions may facilitate the early emergence of sharing behavior, and this effect is mediated by parental empathy. [ABSTRACT FROM AUTHOR]

Looking times (LTs) are frequently measured in empirical research on infant cognition. We analyzed the statistical distribution of LTs across participants to develop recommendations for their treatment in infancy research. Our analyses focused on a common within-subject experimental design, in which longer looking to novel or unexpected stimuli is predicted. We analyzed data from 2 sources: an in-house set of LTs that included data from individual participants (47 experiments, 1,584 observations), and a representative set of published articles reporting group-level LT statistics (149 experiments from 33 articles). We established that LTs are log-normally distributed across participants, and therefore, should always be log-transformed before parametric statistical analyses. We estimated the typical size of significant effects in LT studies, which allowed us to make recommendations about setting sample sizes. We show how our estimate of the distribution of effect sizes of LT studies can be used to design experiments to be analyzed by Bayesian statistics, where the experimenter is required to determine in advance the predicted effect size rather than the sample size. We demonstrate the robustness of this method in both sets of LT experiments. [ABSTRACT FROM AUTHOR]

Four experiments examined how faces compete with physically salient stimuli for the control of attention in 4-, 6-, and 8-month-old infants (N = 117 total). Three computational models were used to quantify physical salience. We presented infants with visual search arrays containing a face and familiar object(s), such as shoes and flowers. Six- and 8-month-old infants looked first and longest at faces; their looking was not strongly influenced by physical salience. In contrast, 4-month-old infants showed a visual preference for the face only when the arrays contained 2 items and the competitor was relatively low in salience. When the arrays contained many items or the only competitor was relatively high in salience, 4-month-old infants' looks were more often directed at the most salient item. Thus, over ages of 4 to 8 months, physical salience has a decreasing influence and faces have an increasing influence on where and how long infants look. [ABSTRACT FROM AUTHOR]