Young infants' remarkable ability to discriminate non-native phoneme contrasts played a critical role in shaping the tenets of the perceptual narrowing hypothesis: early on, infants are sensitive to most phoneme categories, including those not used in their native language, but lose this sensitivity as they attune to their language. However, supporting evidence was derived from limited geographical regions and languages, particularly on early sensitivity, requiring further studies to specify the extent of early sensitivity and reassess the dominant developmental pattern. This study aimed to fill this gap by examining discrimination patterns for three-way Thai stop contrasts by two other Asian language learners (Korean and Japanese) at age 4-6 months. The three stop categories in Thai are distinct along the voice onset time (VOT) dimension, encompassing both negative and positive values. Thai pre-voiced and voiceless (i.e., short lag) stops are similar to stop categories used in languages such as French, Dutch, and Spanish. Thai voiceless and voiceless aspirated (i.e., long lag) stops are similar to those in English, Chinese, and German. Therefore, Thai stop categories provide an ideal test continuum for confirming early universal sensitivities to two supposedly language-general VOT boundaries (-30 ms, +30 ms). We presented two Thai phoneme pairs (pre-voiced vs. voiceless, voiceless vs. voiceless aspirated) to Korean and Japanese infants aged 4-6 months and observed their discrimination patterns using a visual habituation paradigm. The results showed divergent discrimination between the two language learners. Korean infants showed sensitivity to the pre-voiced-voiceless pair, whereas Japanese infants did not. By contrast, only Japanese infants showed some sensitivity to the voiceless-voiceless aspirated pair with some directionality effect, whereas Korean infants did not. These results demonstrate systematic cross-linguistic differences reflecting input influence in early perceptual sensitivity and suggest the ambient language environment may influence consonant perception much earlier than has been considered by the perceptual narrowing theory, calling for further refinement of the extent of initial perceptual state in the theory.

The developmental trajectories of tone perception among tone and non-tone language learning infants have received wide attention and discussion in recent decades under the perceptual attunement framework. Nevertheless, tone perception in infants from pitch accent and bilingual language backgrounds has not been well understood. The present study examined monolingual and bilingual Norwegian-learning infants' discrimination of two Cantonese tone contrasts at 5 and 10 months, ages corresponding to the onset and offset of perceptual attunement. Results showed that while monolingual infants were sensitive to the salient contrast, bilingual infants showed sensitivity to both contrasts at 10 months. In sum, infant age and bilingual language background affected discrimination. Pitch accent language experience or contrast salience may also play a role. The finding that early bilingual experience facilitated tone perception is of particular interest. It suggests that infant perception could be enhanced by a more complex linguistic environment on a broader level. As this was observed only at 10 months, cumulative exposure may be required for infants in a complex bilingual environment. Future studies should disambiguate explanations generated from the current finding, ranging from neurocognitive plasticity to perceptual salience, and from experience-dependent to independent possibilities.

The way in which a mother and her preterm baby interact, especially in moments preceding or following stressful events, is fundamental in shaping the infant's autoregulation. Patterns of mutual sequential coordination constitute stress regulation competences and provide foundation for later socio-emotional development. Maternal affective touch has been postulated as an essential regulatory factor in early social exchange. In this study we aimed to better understand the interplay between maternal affective tactile behaviors and physiological synchrony between mother and child, with possible implications for early bonding processes. Fifteen mother-premature infant dyads were video-recorded during a free interaction and directly after a skin-interrupting medical procedure (vaccination or blood sampling) in the Neonatal Intensive Care Unit. The proportion of maternal affective touch was coded both in free and post-stress interactions. Parasympathetic response was assessed simultaneously in mothers and neonates in order to observe physiological synchrony in dyads. Finally, interactional misattunement during mothers' comforting actions and infant behavior after stress was evaluated as a potential indicator of risk in early bonding processes. Results indicated a positive association between the duration of maternal affective touch and adaptive autonomic synchrony patterns in dyads. Correlations were found between maternal affective touch both before and after stress-inducing procedure and several synchrony measures from free interaction phase (Spearman ρ = -0,57 do 0,72, p < 0,05) Additionally, the study revealed a positive correlation between the level of interactional misattunement and the duration of maternal affective touch after stress (ρ = 0,47, p < 0,05). The quality of synchrony was better in free interactions than during post-stress kangaroo care phase (p < 0,05).

Preterm children are a risk group for neurodevelopmental delays, while interactions with their mothers may serve as a protective factor.

Benefits of attachment security have been demonstrated in multiple realms of development, and an extensive body of research has identified some of the antecedents associated with the development of secure attachments. While previous research has indicated that infant massage may support the development of mothers' attachment to their babies, no published research exists that investigated infants' attachment security after mothers learn infant massage strokes. This study tested the impact of an infant massage intervention on mothers' massage frequency and attachment security in infants. Fifty-eight mother-infant dyads were randomly assigned to a treatment (massage, n = 28) or control (education, n = 30) group. Most mothers had preschool aged children participating in Head Start as well as an infant under 8 months of age; the remaining mothers were from the community. Mothers in the treatment group completed 4 weeks of infant massage training using standard strokes from Infant Massage USA, a chapter of the International Association of Infant Massage, headquartered in Sweden. At 12 months, mothers were guided through the standard sorting procedure of the Attachment Q-set (Waters, 1987). The treatment was effective, as 86 % of mothers in the massage group were still massaging their babies at the follow-up, an average of 10 months later, and infants whose mothers massaged them had higher attachment security scores. Surprisingly, 29 % of the mothers in the comparison group reported that they massaged their babies. A treatment X massage frequency ANOVA indicated that 12-month-old infants whose mothers in the treatment group had massaged them more than once per week were more securely attached than infants of mothers who massaged their infants less than once per week and also were more securely attached than infants in the comparison group. However mothers in the control group defined massage, it was not associated with infant attachment security at the follow-up. These results indicate that this inexpensive, easy to implement intervention effectively increased mothers' ongoing use of infant massage, which in turn predicted more attachment security in their infants.

Gestational Age (GA) at birth plays a crucial role in identifying potential vulnerabilities to long-term difficulties in cognitive and behavioral development. The present study aims to explore the influence of gestational age on the efficiency of early visual attention orienting, as a potential marker for the development of specific high-level socio-cognitive skills. We administered the Gap-Overlap task to measure the attentional orienting and disengagement performance of 16-month-olds born between the 34th and 41st weeks of gestation. Our findings indicate that GA might be a significant predictor of attentional disengagement performance, with lower GAs associated with slower orienting of visual attention in the gap condition. Additionally, we discuss a possible influence of endogenous attention control on disengagement accuracy at this age, particularly among full-term infants. Overall, the findings highlight the role of GA as a key factor in evaluating early visual attention development, acting as a marker for detecting early vulnerabilities.

Neurodevelopmental disability (ND) poses a significant challenge to infants' socio-emotional and cognitive development, as well as to caregiving dynamics, such as parental sensitivity and mother-infant interaction. Prior research highlights the crucial role of early parenting support interventions in enhancing parental behaviors, serving as a protective developmental factor for children at risk for or diagnosed with ND. This single-cohort, multicentric study aims to evaluate the efficacy of early video-feedback intervention (VFI) in improving maternal parenting behaviors. Thirty-four mothers with their children diagnosed with ND participated in the study. Different dimensions of parenting behavior (i.e., affection, responsiveness, encouragement, teaching) were assessed during 10-minute mother-infant interactions, both before (T0) and after (T1) completing six weekly VFI sessions. Additionally, mothers completed standardized questionnaires assessing parenting stress, anxiety, and depressive symptoms. The results indicated significant improvements in maternal responsiveness, encouragement, and teaching following the intervention. Furthermore, mothers reported a state anxiety reduction at T1. Additionally, higher scores in affection and responsiveness were correlated with reduced maternal stress. These findings support the utility of VFI as a valuable tool for enhancing positive parenting skills in the context of ND, and provide insights into the dyadic processes through which parenting behaviors may promote socio-emotional and cognitive development in children with ND.

Babywearing is the practice of carrying an infant in a baby carrier, which may provide an inexpensive, nonpharmacological intervention for the parent-infant dyads to handle mental stressors, such as pain and anxiety, especially among vulnerable infants. This study investigated the influence of babywearing on parent-infant autonomic coregulation based on the changes in the HR of mother-infant and father-infant dyads for infants with neonatal abstinence syndrome (NAS). Guided by the Calming Cycle Theory as the framework, the correlation between parent HR and infant HR and the difference in the mother-infant dyad (n = 17) compared to the father-infant dyad (n = 8) were examined. Although only the mother-infant HRs reached statistical significance during babywearing (r̅ =.52, p = .03), both parent-infant dyads had strong correlations during babywearing (compared to pre- and post-babywearing conditions), indicating that babywearing, for parents and their infants with NAS, may influence autonomic coregulation.

Forty years ago, Werker and Tees (1984) published a seminal finding which launched a proliferation of new research on early language learning. Their startling discovery, that infants demonstrate high initial sensitivity to phonetic contrasts which then attenuates over the first year of life, has provided deep insights into the origins of language learning. It has since stimulated a significant body of research investigating this early developmental process. This vast body of empirical work led to a theory of perceptual narrowing, which prevails today as a domain-general mechanism of environmental adaptation. In this article, I offer future directions for empirical and theoretical growth of perceptual narrowing theory with particular attention to issues of diversity, representation and generalizability. In addition, I discuss the importance of integrating empirical variation into perceptual narrowing theory.

The purpose of this research was to examine the role of a range of play and learning activities in the home (e.g., painting, playing games, reading, singing and letters and numbers) in the socioemotional development of young children. While many previous studies have focused on the benefits of home learning activities for language and literacy outcomes, less research has examined the role of these individual activities in other aspects of development, such as prosocial behaviour. Using a bioecological framework, a secondary analysis of data from the nationally representative Growing Up in Ireland(GUI) Study was conducted. The sample consisted of 9793 children, aged 36 months (50.7 % male and 49.3 % female). The study examined if the frequency of engagement in different play activities predicted scores on measures of internalising, externalising and prosocial behaviours using the Strengths and Difficulties Questionnaire. Findings indicated that informal play activities such as games, painting and drawing, and reading predicted socioemotional development scores, in comparison with activities such as letter or number games, even after parental and other family factors are accounted for. The results also indicated that parent-child relationship factors of warmth, hostility and closeness are particularly important for socioemotional development. Findings are discussed in the context of Bronfenbrenner's bioecological model of development.

Recent research has shown that children as young as 19 months demonstrate graded sensitivity to mispronunciations in consonant onsets and vowels in word recognition tasks. This is evident in their progressively diminishing attention to relevant objects (e.g., a dog) as mispronunciations increasingly deviate from the correct word form (such as /dog/ changing to /gog/, /kog/, or /sog/). Despite these sensitivities, uncertainties remain about their broad generalizability, especially regarding the differences between word onsets and codas, and between lexical segmental (consonants and vowels) and supra-segmental (e.g., lexical stress and tones) elements. The present study aimed to fill these gaps. Using the intermodal preferential paradigm, we conducted two experiments to evaluate toddlers' responses to coda and lexical tone mispronunciations. Our results revealed a linear decline in toddlers' attention to familiar objects as mispronunciations became more severe, suggesting that by 19-20 months, infants' lexical representations encompass detailed phonetic information of both segmental and supra-segmental categories. Moreover, our results indicate that toddlers utilize these details in lexical processing. Such findings offer a more comprehensive understanding of the phonetic structures within toddlers' early lexical representations, sheding light on the mechanisms toddlers use in processing various word positions, across different acoustic dimensions, and in multiple languages.

In previous research, infants' performance on speech perception tasks has been shown to predict later language outcomes, typically vocabulary size. We used Bayesian analyses to model trial-level looking time behavior of individual infants on morphological segmentation experiments. We compared the usefulness of Bayesian estimates and the raw looking time difference measures used in previous studies to predict (a) vocabulary size at 30 months and (b) outcome measures obtained from language samples elicited via a picture description task at 36 months. We found that both estimates of morphological segmentation reliably predicted expressive vocabulary at 30 months. The Bayesian estimate also credibly predicted the correct use of verb tense morphemes obtained from the language sample. We therefore conclude that the Bayesian estimate is better for indexing individual differences in segmentation tasks and more useful for predicting clinically relevant language outcomes.

Before infants walk independently, they move upright with support by holding caregivers' hands, pushing a wheeled walker, and "cruising" along walls or furniture. To what extent do caregivers and infants engage in these activities and do these experiences with supported walking relate to independent walking status? To address these questions, we assessed supported walking in 50 11-month-olds and their mothers in the context of everyday routines. For each bout of supported walking, coders scored the type of support, frequency of supported bouts, and the number of steps infants took per bout. Mothers tracked onset ages for independent walking prospectively, and researchers verified infants' walking skill using a standardized task. Infants who produced more child-controlled supported walking achieved independent walking earlier than infants who produced less child-controlled supported walking. But, supported walking experience did not predict proficiency of independent walking, suggesting that the two types of locomotion are distinct. These data highlight the role of experience of locomotor behaviors and indicate that not all experience is equally effective.

This study investigates the sensory processing of typically developing toddlers with and without sleep problems. The research group consisted of typically developing toddlers with sleep problems (n = 110, mean age=18.35 ± 3.4 months), while the control group included typically developing toddlers without sleep problems (n = 110, mean age=18.67 ± 3.5 months) and their mothers. Toddlers were assigned to the research and control groups based on their sleep problems, as determined by the Brief Infant Sleep Questionnaire. The sensory processing of the toddlers was evaluated using the Infant/Toddler Sensory Profile 2. Sensory patterns and sensory processing sub-parameters of the research and control groups were compared. The sensory processing of the research group showed atypical behavioral responses in low registration (low awareness or indifferent attitude to sensory stimuli), sensory sensitivity (distracted or irritable attitude, intensely stimulated by sensory stimuli), and sensory avoiding (intentional avoidance of sensory stimuli or attitudes that produce out-of-norm responses) patterns compared to the control group (p < 0.05). Behavioral responses were similar in the sensory seeking (disturbing or dangerous attitude to the environment in search of sensory stimuli) pattern (p > 0.309). Statistically significant differences were observed in all sub-parameters of sensory processing compared to the control group. Our findings indicate that toddlers with sleep problems are at risk for sensory processing issues. Toddlers with sleep problems exhibit atypical sensory responses related to sensory sensitivity, low registration, and sensory avoiding. It should be considered that toddlers with sleep problems may show sensitivity to different sensory stimuli, avoidance or may not be able to recognize sensory stimuli. These findings suggest that the inclusion of sensory profile assessments in interdisciplinary care for toddlers with sleep problems may contribute to parent-infant well-being.

Positive mother-infant interactions are important for infant development. Both mother and infant characteristics, such as maternal depression and infant temperamental negative affect are risk factors for adverse mother-infant bonding and infant outcomes. Although these predictors have been researched individually, limited studies have considered them in concert. This study aimed to examine the role of infant age (6-, 9- and 12-months), infant temperamental negative affect, and maternal depression on maternal and infant social positive engagement during the Still-Face procedure. Participants were 85 ethnically-varied mother-infant dyads (44 % girls). Mothers responded to questionnaires, prior to attending the laboratory for the Still-Face procedure (i.e., a task involving a social stressor). Results showed a significant moderating relationship between infant age, infant temperamental negative affect, and maternal depression on infant social positive engagement. For 12-month-old infants, higher infant temperamental negative affect was found to be compounded by greater maternal depression symptoms resulting in significantly lower social positive engagement following a social stressor. This relationship was not found for younger infants. No predictors were associated with maternal social positive engagement. Results from this study contribute to the literature on infant wellbeing. Results highlight the importance of interventions that aim to reduce maternal depression symptoms, especially, as maternal depression may disproportionately influence 12-month-old infants who have negative temperament.

Classic attachment theory emphasizes the sensitivity of the parent to perceive and appropriately respond to the infant's cues. However, parent-child attachment is a dyadic interaction that is also dependent upon the sensitivity of the child to the early caregiving environment. Individual differences in infant sensitivity to parental cues is likely shaped by both the early caregiving environment as well as the infant's neurobiology, such as perceptual sensitivity to social stimuli. Here, we investigated associations between maternal postpartum depression and infant neurological sensitivity to affective touch using brain signal entropy - a metric of the brain's moment-to-moment variability related to signal processing. We recruited two independent samples of infants aged 0-5 months. In Sample 1 (n = 79), we found increased levels of maternal postpartum depression were associated with diminished perceptual sensitivity - i.e. lower entropy - to affective tactile stimulation specifically within the primary somatosensory cortex. In Sample 2 (n = 36), we replicated this finding and showed that this effect was not related to characteristics of the touch administered during the experiment. These results suggest that decreased affective touch early in life - a common consequence of postpartum depression - likely impacts the infant's perceptual sensitivity to affective touch and ultimately the formation of experience-dependent neural networks that support the successful formation of attachment relationships.

In the current preregistered study, we tested n = 67 6-month-old Norwegian infants' discrimination of a native vowel contrast /y-i/ and a non-native (British) vowel contrast /ʌ-æ/ in an eye-tracking habituation paradigm. Our results showed that, on a group level, infants did not discriminate either contrast. Yet, exploratory analyses revealed a negative association between infants' performance in each experiment, that is, better discrimination of the native contrast was associated with worse discrimination of the non-native contrast. Potentially, infants in this study might have been on the cusp of perceptual reorganisation towards their native language.

Young infants can discriminate many non-native sounds, but the discrimination ability is thought to decrease within the first year of life due to perceptual attunement. However, most studies tested infants' perception cross-sectionally, without examining within-group change. To this end, the current study tested German infants' discrimination of the English /æ/-/ɛ/ contrast both cross-sectionally and longitudinally using the visual habituation technique. In Experiment 1, 96 German-learning infants were tested cross-sectionally at 5-6, 8-9 and 12-13 months. Linear mixed-effects models revealed that while the 5-6-month-olds did not discriminate the contrast, the 8-9- and 12-13-month-olds showed signs of discrimination only when they were habituated with /ɛ/, in line with previous findings suggesting that changes from central to peripheral vowels in the F1/F2 vowel space are more noticeable than in the reverse direction. Moreover, the 8-9-month-olds showed a novelty preference, while the 12-13-month-olds showed a familiarity preference. In Experiment 2, the infants tested at 5-6 months in Experiment 1 were tested again at 8-9 and 12-13 months. Fifteen infants completed the three experiments. Here, only the 12-13-month-olds discriminated the contrast by showing a novelty preference but only when habituated with /æ/. Overall, both experiments showed gradual development of discrimination ability across the first year, which challenges the assumptions of perceptual attunement. We propose that the perceptual sensitivity for a non-native vocalic contrast can improve during development. The change in perceptual asymmetry tells us that the direction of asymmetry is not universal and can be altered by linguistic experience. The change from novelty to familiarity preference may be due to the emerging preference for the more native-like vowel as well as the effect of repeating experiments with the same infants. In sum, our cross-sectional and longitudinal results overlap broadly, but the potential effect of repeating experiments must be considered when interpreting longitudinal studies.

The aim of this study was to explore the relationship between breastfeeding duration and neurodevelopment in children aged 2 to 3 years in a Chinese population.

This study investigated if non-nutritive suck (NNS) at 3 months is related to subsequent oral motor and motor skills using caregiver-reported scores on the Child Oral and Motor Proficiency Scale (ChOMPS) at 12 months in a cohort of 69 full-term infants and their caregivers. Longer NNS burst durations were associated with lower oral motor coordination and total ChOMPS scores. More NNS cycles per minute was associated with lower complex motor movement scores. More NNS bursts, cycles per burst, and cycles per minute were related with lower total ChOMPS scores. Early NNS outcomes can provide valuable insight in future neuromotor development.

Any experiment brings about results and conclusions that necessarily have a component of uncertainty. Many factors influence the degree of this uncertainty, yet they can be overlooked when drawing conclusions from a body of research. Here, we showcase how subjective logic could be employed as a complementary tool to meta-analysis to incorporate the chosen sources of uncertainty into the answer that researchers seek to provide to their research question. We illustrate this approach by focusing on a body of research already meta-analyzed, whose overall aim was to assess if human infants prefer prosocial agents over antisocial agents. We show how each finding can be encoded as a subjective opinion, and how findings can be aggregated to produce an answer that explicitly incorporates uncertainty. We argue that a core feature and strength of this approach is its transparency in the process of factoring in uncertainty and reasoning about research findings. Subjective logic promises to be a powerful complementary tool to incorporate uncertainty explicitly and transparently in the evaluation of research.

Autism Spectrum Disorder is a highly heritable condition characterized by sociocommunicative difficulties, frequently entailing language atypicalities that extend to infants with a familial history of autism. The developmental mechanisms underlying these difficulties remain unknown. Detecting temporal synchrony between the lip movements and the auditory speech of a talking face and selectively attending to the mouth support typical early language acquisition. This preliminary eye-tracking study investigated whether these two fundamental mechanisms atypically function in infant siblings. We longitudinally tracked the trajectories of infants at elevated and low-likelihood for autism in these two abilities at 4, 8, and 12 months (n = 29). We presented two talking faces (synchronous and asynchronous) while recording infants' gaze to the talker's eyes and mouth. We found that infants detected temporal asynchronies in talking faces at 12 months regardless of group. However, compared to their typically developing peers, infants with an elevated likelihood of autism showed reduced attention to the mouth at the end of the first year and no variations in their interest to this area across time. Our findings provide preliminary evidence on a potentially atypical trajectory of reduced mouth-looking in audiovisual speech during the first year in infant siblings, with potential cascading consequences for language development, thus contributing to domain-general accounts of emerging autism.

Language development during the 1st year of life is characterized by perceptual attunement: following language-general perception, a decline in the perception of non-native phonemes and a parallel increase in or maintenance of the perception of native phonemes. While this general pattern is well established, there are still many gaps in the literature. First, most evidence documenting these patterns comes from "Minority world countries" with only a limited number of studies from "Majority world countries", limiting the range of languages and contrasts assessed. Second, few studies test both the developmental patterns of native and non-native speech perception in the same group of infants, making it hard to draw conclusions on simultaneous decline in non-native and increase in native speech perception. Such limitations are in part due to the effort that goes into testing developing speech sound perception, where usually only discrimination of one contrast per infant can be tested at a time. The present study thus set out to assess the feasibility of assessing a given infant on their discrimination of two speech sound contrasts during the same lab visit. It leveraged the presence of documented patterns of the improvement of native and the decline of non-native phoneme discrimination abilities in Japanese, therefore assessing native and non-native speech perception in Japanese infants from 6 to 12 months of age. Results demonstrated that 76 % of infants contributed discrimination data for both contrasts. We found a decline in non-native speech perception evident in discrimination of the non-native /ɹ/-/l/ consonant contrast at 9-11, but not at 11-13 months of age. Additionally, a parallel increase in native speech perception was demonstrated evident in an absence of native phonemic vowel length discrimination at 6-7 and 9-11 months and a discrimination of this contrast at 11-13 months of age. These results, based on a simultaneous assessment of native and non-native speech perception in Japanese-learning infants, demonstrate the feasibility of assessing the discrimination of two contrasts in one testing session and corroborate theoretical proposals on two hallmarks of perceptual attunement: a decrease in non-native and a facilitation in native speech perception during the first year of life.

Positive affect synchrony, or the reciprocal exchange of positive affect during free play, can scaffold infants' socioemotional development. However, parental stress may compromise the expression and exchange of positive affect within families. The current study assesses whether parenting stress and hair cortisol are associated with positive affect synchrony during a triadic play interaction.

Perceptual narrowing typically occurs around 6 months of age, and drastically changes an infant's perception of stimuli such as faces or spoken language according to the frequency with which the infant encounters them. It has already been well established that perceptual narrowing improves the sensitivity of infants to frequently encountered stimuli such as same-race faces and their native language while reducing their sensitivity to other-race faces and non-native languages. However, the effect of perceptual narrowing on the combined perception of face and language stimuli is not well understood. Therefore, to investigate the changes in the sensitivity of infants to matches and mismatches between faces and speech which might occur in the course of perceptual narrowing, we tested 3- and 9-month-old German infants using German faces and German spoken sentences which would be familiar to the infants, as well as completely unfamiliar Chinese faces and French spoken sentences. The infants were tested using an intermodal association paradigm, whereby each infant saw sequences of German or Chinese faces, interspersed with German or French spoken sentences. We analyzed the total looking time of infants in conditions where the faces and spoken sentences were congruent (either both familiar, or both unfamiliar), versus incongruent conditions where only the faces or only the sentences were familiar. We found that while the 9-month-olds looked for similar durations in congruent versus incongruent conditions, the 3-month-olds looked significantly longer during congruent conditions versus incongruent conditions, indicating a greater attentiveness to face-speech matches and mismatches prior to the onset of perceptual narrowing.

Previous work has shown that caregiver attention shapes visual cognition in infants through dyadic interactions. Is this association measurable when visual cognition is objectively measured in caregivers and infants using comparable experimental paradigms? In the current study, we presented infants (N = 86) and caregivers (N = 78) with age-specific variants of the same preferential looking visual cognition task to investigate whether caregiver visual cognition was associated with their infants' visual cognition. In each trial of the task, two side-by-side flashing displays of coloured shapes were presented. On the 'unchanging' side, the colours of the shapes remained the same. On the 'changing' side, the colour of one shape changed after each flash. Load was varied by changing the number of shapes across trials (low, medium, and high loads). We extracted looking dynamics using video recordings and brain function using functional near-infrared spectroscopy as both infants and caregivers engaged with the task. Change preference (CP) score, which represented the amount of time spent looking at the changing side divided by the total looking duration, showed a load-dependent modulation for both infants and caregivers. Both groups showed the highest CP scores at the low load. Further, higher caregiver CP scores was associated with higher infant CP scores at the low load. Both infants and caregivers engaged canonical regions of the fronto-parietal network involved in visual cognition. Critically, higher caregiver CP scores were associated with greater activation in the left superior parietal lobule in younger infants, a region involved in allocating visuo-spatial attention and working memory maintenance. Further, there was spatial overlap between performance-dependent regions in the right parietal cortex in caregivers and younger infants. Our findings provide first evidence of a heritability-related visual neurocognitive association between caregivers and their children in the first year of life.

The present study investigated the potential for sensitizing 2.5-year-old Caucasian infants to other-race faces (Asian faces). In the domain of face perception, infants become less sensitive to facial distinctions of other-race faces through perceptual narrowing at the end of the first year of life. Nevertheless, infants around 12 months can regain their sensitivity to other-race faces. For instance, exposing them to a specific statistical distribution and employing the mechanisms of statistical learning is one way to enhance their discriminatory abilities towards other-race faces. Following this idea, we investigated if even older infants around 2.5 years can be sensitized to other-race faces. We trained the infants with a bimodal distribution of a morphed continuum of Asian female faces with faces closer to the endpoints presented most frequently. We assessed infants' discrimination of Asian faces by measuring their looking times after the training phase. The 2.5-year-olds showed a difference in looking times after the training, indicating that the exposure to a bimodal frequency distribution led to a successful discrimination between Asian faces. These findings demonstrate that 2.5-year-olds can be sensitized to other-race faces by exposing them to a bimodal distribution of such faces, underlining the plasticity of face perception in childhood.

Identifying the type of mechanisms at the core of phonetic categorization remains a central subject of research in infant language learning. Amongst different theories, one is that infants compute distributional information of phonemes based on their surrounding sounds (i.e., word context) such that phonemes that appear in different word contexts are more likely to be discriminated and categorized separately than phonemes that appear in similar word contexts. Following the procedure of Feldman et al. (2013a), we investigated the role of contextual information in the acquisition of phonetic categories in 8-month-old infants, using a non-native vowel contrast (English /ɒ/-/ʌ/). In Experiment 1, we established lack of discrimination of the non-native contrast without prior exposure to it. In Experiment 2, we manipulated the type of exposure prior to testing: half of the infants were exposed to minimal pair carriers (words that differ by one phoneme only; e.g., lituh and litoh), and the other half of the infants were exposed to non-minimal pair carriers (words formed by different phonemes; e.g., lituh and nutoh). All infants were tested for discrimination of the contrast (tuh vs. toh) presented as alternating (e.g., tuh-toh-tuh-toh) and non-alternating trials (e.g., tuh-tuh-tuh), as in Experiment 1. Infants in both conditions looked on average longer at alternating rather than non-alternating trials, suggesting that they discriminated the /ɒ/-/ʌ/ contrast after a brief exposure to the vowels embedded into words. Crucially, discrimination occurred regardless of whether words were minimal pair carriers or non-minimal pair carriers. A cross-experiment comparison revealed that infants showed different patterns of looking times based on whether they were exposed to the contrast before testing (Experiment 2) or not (Experiment 1). Our study shows that any type of word context helps infants to re-establish discrimination of non-native contrasts once sensitivity has been lost. These findings aid to better understand how the speech input modulates learning mechanisms during the establishment of phonetic categories in the first year of postnatal life.

Distributional learning has been proposed as a mechanism for infants to learn the native phonemes of the language(s) to which they are exposed. When hearing two speech streams, bilingual infants may find other strategies more useful and rely on distributional learning less than monolingual infants. A series of studies examined how bilingual language experience affects the application of the distributional learning to novel phoneme distributions. Monolingual and bilingual infants between 6 and 8 months old performed a distributional learning task using palatal consonant stimuli grouped into one of three distributions based on voice onset time. Performance after exposure to a unimodal distribution was compared to performance after both a bimodal (Experiment 1) and trimodal distribution (Experiment 2) of the same voice onset time cue. Results indicated that monolingual and bilingual infants performed similarly on all tasks, and infants were able to learn both bimodal and trimodal phoneme distributions. The universality of the distributional learning mechanism is suggested by these results, but future research would need to test the two groups and distributions for equivalence of performance.