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By the end of the first year of life, infants' discrimination abilities tune to frequently experienced face groups. Little is known about the exploration strategies adopted to efficiently discriminate frequent, familiar face types. The present eye-tracking study examined the distribution of visual fixations produced by 10-month-old and 4-month-old singletons while learning adult (i.e., familiar) and child (i.e., unfamiliar) White faces. Infants were tested in an infant-controlled visual habituation task, in which post-habituation preference measured successful discrimination. Results confirmed earlier evidence that, without sibling experience, 10-month-olds discriminate only among adult faces. Analyses of gaze movements during habituation showed that infants' fixations were centered in the upper part of the stimuli. The mouth was sampled longer in adult faces than in child faces, while the child eyes were sampled longer and more frequently than the adult eyes. At 10 months, but not at 4 months, global measures of scanning behavior on the whole face also varied according to face age, as the spatiotemporal distribution of scan paths showed larger within- and between-participants similarity for adult faces than for child faces. Results are discussed with reference to the perceptual narrowing literature, and the influence of age-appropriate developmental tasks on infants' face processing abilities.

Statistical learning refers to the ability to extract the statistical relations embedded in a sequence, and it plays a crucial role in the development of communicative and social skills that are impacted in the Autism Spectrum Disorder (ASD). Here, we investigated the relationship between infants’ SL ability and autistic traits in their parents. Using a visual habituation task, we tested infant offspring of adults (non-diagnosed) who show high (HAT infants) versus low (LAT infants) autistic traits. Results demonstrated that LAT infants learned the statistical structure embedded in a visual sequence, while HAT infants failed. Moreover, infants’ SL ability was related to autistic traits in their parents, further suggesting that early dysfunctions in SL might contribute to variabilities in ASD symptoms.

The Dynamic Attending Theory postulates that ongoing temporal structure of events entrains attention and affects perception (Jones et al., 2002). According to this theory, rhythm, defined as a sequence of short repeated intervals with regularities that allow us to build expectancies, is one of the main temporal cue which guides attention and facilitates performances in both visual and auditory domains. Evidence from the adult literature supports this hypothesis, showing that rhythm boosts perception (e.g., Elbaz & Yeshurun, 2020). However, no study has explored whether the rhythmic structure of external stimuli improves the efficiency with which infants attend to and process them. Given the ubiquitous nature of rhythms in the perceptual environment of the infant across the perinatal period, this question appears compelling. Indeed, it has been shown that foetuses in the last trimester of gestation are responsive to rhythmic stimulation that reaches them through the auditory, vestibular and tactile sensory channels (Lecanuet & Schaal, 2002), and it is claimed that this early exposure to rhythm plays a key role in the development of early communicative and cognitive abilities (Provasi et al., 2014). On this ground, we hypothesised that exposing the foetus to an enriched rhythmic environment might affect early infants’ attentional capabilities, which could be boosted by prenatal experience. The current study is part of a larger project aimed at testing this hypothesis, and was planned as a pilot investigation of the impact of rhythm on the orienting of visual spatial attention at birth. Two-day-old newborns were tested in an overlap task where a central stimulus, S1, was followed by a peripheral target, S2, (see Fig.1) and saccadic reaction times towards S2 were recorded as measure of attentional disengagement. S1 remained on the screen until the infant’s gaze landed on S2. On each trial, the same image was presented as S1 and S2. We manipulated the attributes of S1 within-subjects to obtain three different S1 conditions: the Static condition, in which S1 remained still on the screen, the Rhythmic condition, in which S1 flickered at the rate of 500 ms on and 400 ms off, and the Random condition, in which S1 flickered at a random rate. We planned to reach a sample size of at least N = 28, as resulting from an a-priori power analysis. Data collection is still in progress. Preliminary results from the first 6 newborns suggest that both the dynamic and rhythmic nature of the central stimulus affected saccadic latency, as the static condition induced the fastest latencies, and the rhythmic condition is associated with the slowest latencies. If confirmed by the data from the final sample, this pattern of results would suggest that rhythm is perceived as particularly salient and captivating at birth, thus constraining the efficiency of attentional orienting.

Recent evidence shows that preverbal infants raised in Western cultures represent increasing numerical order and extract rule-like patterns from visual sequences when items are presented from left to right, but not right to left. These findings match earlier demonstrations that adults and preliterate children represent numerical and/or non-numerical order along a spatial continuum whose directional attributes are shaped by reading-writing direction. Here we explored the developmental origins of the directional properties of order-space mapping by testing whether/how visual rule learning (RL) abilities are affected by the spatial orientation of the sequences in 115 Italian and 120 Japanese 7-month-old infants, whose cultures differ for the unidimensional vs multidimensional structure of their reading-writing systems. Infants were familiarized with rule-based sequences of visual shapes presented in a left-to-right, right-to-left, top-to-bottom or bottom-to-top orientation. They were then tested with six sequences of novel shapes depicting the familiar or a novel rule presented with the familiar orientation. Results showed that Italian infants succeeded at RL only when sequences were left-to-right and top-to-bottom oriented (Novelty x Direction, p=.019), while Japanese infants succeeded in all conditions, irrespective of the spatial direction of the sequences (ps

By 27-week gestation the brain undergoes extensive changes driven by external input, suggesting that learning occurs even before birth. Much of the sensory input that reaches the foetus has a rhythmic structure, and literature suggests that intrauterine rhythmic experience may contribute to the emergence of complex skills during postnatal life. Adult studies show that rhythm entrains attention enhancing information processing. Here, we hypothesised that exposure to rhythmic stimulation may boost attention from the earliest stages of neurodevelopment. To this end, we tested the short- and long-term effects of enriched multisensory rhythmic stimulation provided across the last trimester of gestation on visual spatial attention at birth and 2 months postpartum. Starting from 29-week gestation two groups of mothers follows a rhythmic or non-rhythmic stimulation protocol, and infants’ visuo-spatial attention skills are tested at birth and 2 months using a disengagement task in which accuracy and latency of orienting toward a peripheral target are measured as a function of the rhythmic vs random temporal structure of a central cue. Data collection is in progress: we expect rhythm to constrain the efficiency of attentional orienting differently for infants in the two groups.

Developmental studies have shown that infants exploit ordinal information to extract and generalize repetition-based rules from a sequence of items. Within the visual modality, this ability is constrained by the spatial layout within which items are delivered given that a left-to-right orientation boosts infants' rule learning, whereas a right-to-left orientation hinders this ability. Infants' rule learning operates across different domains and can also be transferred across modalities when learning is triggered by speech. However, no studies have investigated whether the transfer of rule learning occurs across different domains when language is not involved. Using a visual habituation procedure, we tested 7-month-old infants' ability to extract rule-like patterns from numerical sequences and generalize them to non-numerical sequences of visual shapes and whether this ability is affected by the spatial orientation. Infants were first habituated to left-to-right or right-to-left oriented numerical sequences instantiating an ABB rule and were then tested with the familiar rule instantiated across sequences of single geometrical shapes and a novel (ABA) rule. Results showed a transfer of learning from number to visual shapes for left-to-right oriented sequences but not for right-to-left oriented ones (Experiment 1) even when the direction of the numerical change (increasing vs. decreasing) within the habituation sequences violated a small-left/large-right number-space association (Experiment 2). These results provide the first demonstration that visual rule learning mechanisms in infancy operate at a high level of abstraction and confirm earlier findings that left-to-right oriented directional cues facilitate infants' representation of order.

Research has shown that adults are better at processing faces of the most represented ethnic group in their social environment compared to faces from other ethnicities, and that they rely more on holistic/configural information for identity discrimination in own-race than other-race faces. Here, we applied a spatial filtering approach to the investigation of trustworthiness perception to explore whether the information on which trustworthiness judgments are based differs according to face race. European participants (N = 165) performed an online-delivered pairwise preference task in which they were asked to select the face they would trust more within pairs randomly selected from validated White and Asian broad spectrum, low-pass filter and high-pass filter trustworthiness continua. Results confirmed earlier demonstrations that trustworthiness perception generalizes across face ethnicity, but discrimination of trustworthiness intensity relied more heavily on the LSF content of the images for own-race faces compared to other-race faces. Results are discussed in light of previous work on emotion discrimination and the hypothesis of overlapping perceptual mechanisms subtending social perception of faces.

The ability of infants to track transitional probabilities (Statistical Learning—SL) and to extract and generalize high-order rules (Rule Learning—RL) from sequences of items have been proposed as being pivotal for the acquisition of language and reading skills. Although there is ample evidence of specific associations between SL and RL abilities and, respectively, vocabulary and grammar skills, research exploring SL and RL as early markers of language and learning (dis)abilities is still scarce. Here we investigated the efficiency of visual SL and RL skills in typically developing (TD) seven-month-old infants and in seven-month-old infants at high risk (HR) for language learning impairment. Infants were tested in two visual-habituation tasks aimed to measure their ability to extract transitional probabilities (SL task) or high-order, repetition-based rules (RL task) from sequences of visual shapes. Post-habituation looking time preferences revealed that both TD and HR infants succeeded in learning the statistical structure (SL task), while only TD infants, but not HR infants, were able to learn and generalize the high-order rule (RL task). These findings suggest that SL and RL may contribute differently to the emergence of language learning impairment and support the hypothesis that a mechanism linked to the extraction of grammar structures may contribute to the disorder.

Rule learning (RL) refers to infants’ ability to extract high‐order, repetition‐based rules from a sequence of elements and to generalize them to new items. RL has been demonstrated in both the auditory and the visual modality, but no studies have investigated infants’ transfer of learning across these two modalities, a process that is fundamental for the development of many complex cognitive skills. Using a visual habituation procedure within a cross‐modal RL task, we tested 7‐month‐old infants’ transfer of learning both from speech to vision (auditory‐visual—AV—condition) and from vision to speech (visual‐auditory—VA—condition). Results showed a transfer of learning in the AV condition, but only for those infants who were able to efficiently extract the rule during the learning (habituation) phase. In contrast, in the VA condition infants provided no evidence of RL. Overall, this study indicates that 7‐month‐old infants can transfers high‐order rules across modalities with an advantage for transferring from speech to vision, and that this ability is constrained by infants’ individual differences in the way they process the to‐be‐learned rules.

Infant research is providing accumulating evidence that number-space mappings appear early in development. Here, a Posner cueing paradigm was used to investigate the neural mechanisms underpinning the attentional bias induced by nonsymbolic numerical cues in 9-month-old infants (N=32). Event-related potentials and saccadic reaction time were measured to the onset of a peripheral target flashing right after the offset of a centered small or large numerical cue, with the location of the target being either congruent or incongruent with the number’s relative position on a left-to-right oriented representational continuum. Results indicated that the cueing effect induced by numbers on infants’ orienting of eye gaze brings about sensory facilitation in processing visual information at the cued location.

Discriminating facial cues to trustworthiness is a fundamental social skill whose developmental origins are still debated. Prior investigations used computer-generated faces, which might fail to reflect infants' face processing expertise. Here, Event-Related Potentials (ERPs) were recorded in Caucasian adults (N = 20, 7 males, M age = 25.25 years) and 6-month-old infants (N = 21, 10 males) in response to variations in trustworthiness intensity expressed by morphed images of realistic female faces associated with explicit trustworthiness judgments (Study 1). Preferential looking behavior in response to the same faces was also investigated in infants (N = 27, 11 males) (Study 2). ERP results showed that both age groups distinguished subtle stimulus differences, and that interindividual variability in neural sensitivity to these differences were associated with infants' temperament. No signs of stimulus differentiation emerged from infants' looking behavior. These findings contribute to the understanding of the developmental origins of human sensitivity to social cues from faces by extending prior evidence to more ecological stimuli and by unraveling the mediating role of temperament.

The ability to discriminate the ordinal information embedded in magnitude-based sequences has been shown in 4-month-old infants, both for numerical and size-based sequences. At this early age, however, this ability is confined to increasing sequences, with infants failing to extract and represent decreasing order. Here we investigate whether the ability to represent order extends to duration-based sequences in 4-month-old infants, and whether it also shows the asymmetry signature previously observed for number and size. Infants were tested in an order discrimination task in which they were habituated to either increasing or decreasing variations in temporal duration, and were then tested with novel sequences composed of new temporal items whose durations varied following the familiar and the novel orders in alternation. Across three experiments, we manipulated the duration of the single temporal items and therefore of the whole sequences, which resulted in imposing more or less constraints on infants’ working memory, or general processing capacities. Results showed that infants failed at discriminating the ordinal direction in temporal sequences when the sequences had an overall long duration (Experiment 1), but succeeded when the duration of the sequences was shortened (Experiments 2 and 3). Moreover, there was no sign of the asymmetry signature previously reported for number and size, as successful discrimination was present for infants habituated to both increasing and decreasing sequences. These results suggest that sensitivity to temporal order is present very early in development, and that its functional properties are not shared with other magnitude dimensions, such as size and number.

Recent evidences show that, preverbal infants’ ability to learn abstract rules from ordered visual sequences (Rule Learning) is influenced by the spatial information. For example, 7-month-old Italian infants can learn ABB/ABA abstract rules from sequences of geometrical shapes when sequences are presented from left to right, while they fail with a right to left presentation. This study is aimed at investigating whether the modulation of spatial information on infants’ learning abilities can be generalized also to an AAB rule, i.e. a rule that can be learned only from 11 months of age when spatial information is not available. Results confirm that infants are able to learn both the ABB/ABA rules and the new AAB rule, and that this ability is present only when sequences are presented from left to right.

The ability to learn and generalize abstract rules from sensory input - i.e., Rule Learning (RL) - is seen as pivotal to language development, and specifically to the acquisition of the grammatical structure of language. Although many studies have shown that RL in infancy is operating across different perceptual domains, including vision, no studies have directly investigated the link between infants' visual RL and later language acquisition. Here, we conducted a longitudinal study to investigate whether 7-month-olds' ability to detect visual structural regularities predicts linguistic outcome at 2 years of age. At 7 months, infants were tested for their ability to extract and generalize ABB and ABA structures from sequences of visual shapes, and at 24 months their lexical and grammatical skills were assessed using the MacArthur-Bates CDI. Regression analyses showed that infants' visual RL abilities selectively predicted early grammatical abilities, but not lexical abilities. These results may provide the first evidence that RL mechanisms are involved in language acquisition, and suggest that RL abilities may act as an early neurocognitive marker for language impairments.

Space-number and space-time associations have been a timely topic in the cognitive sciences for years, but evidence from developmental populations is still scarce. In particular, it remains to be established whether space-number and space-time mappings are anchored onto the same spatial frame of reference across development. To explore this issue, we manipulated visual and proprioceptive feedback in a Number Comparison task (Experiment 1) and a Time Comparison task (Expriment 2), in which 6- and 10-year-old children had to classify numerical and temporal words by means of a lateralised response with or without a blindfold (visual manipulation), and with hands uncrossed or crossed over the body midline (proprioceptive manipulation). Results revealed that 10-year-old children were more efficient in associating smaller numbers and past events with the left key, and larger numbers and future events with the right key, irrespective of the visual and proprioceptive manipulations. On the contrary, younger children did so only in the Time Comparison task, but not in the Number Comparison task. In the latter task, 6-year-olds associated small/large numbers with the left/right side of space only in the presence of visual feedback, but not when blindfolded. Taken together, our findings unveil that in school-aged children the spatial representation of number and time develop on different spatial frames of reference: while space-time associations exclusively rely on external coordinates at age 6, space-number associations shift from mixed internal and external coordinates at age 6 to more adult-like external coordinates by age 10.

La discriminazione del livello di affidabilità espresso dai volti è un processo rapido e automatico con una forte rilevanza adattiva. Il presente studio indaga la natura delle informazioni visive su cui si fondano i giudizi di affidabilità attraverso la rimozione selettiva di diverse porzioni di frequenze spaziali alte o basse. Attraverso un compito online, ad un gruppo di adulti è stato chiesto di giudicare il livello di affidabilità percepita espressa da due volti femminili in cinque diverse condizioni di filtraggio. I risultati mostrano che, nonostante sia le alte sia le basse frequenze siano sufficienti per discriminare tra volti ad alta e bassa affidabilità, i giudizi sono più accurati quando nelle immagini sono disponibili le sole basse frequenze spaziali rispetto a quando sono visibili solo le alte frequenze. Le evidenze ottenute sono discusse nel contesto della letteratura sull’elaborazione delle espressioni emotive Summary. The discrimination between trustworthy and untrustworthy faces is an automatic and rapid process with a strong adaptive meaning. The present study aims to investigate the nature of the visual information trustworthiness perception relies on by selectively removing different portions of high and low spatial frequencies. By participating in an online task, adult participants judged trustworthiness intensity expressed by high and low trustworthy female faces under five spatial filtering conditions. Results show that, although both high and low spatial frequencies provide sufficient cues for discriminating between trustworthy and untrustworthy faces, trustworthiness judgments are more accurate when only low spatial frequencies are available in the stimuli. Results are discussed with reference to the literature on emotion discrimination.

An Operational Momentum (OM) effect is shown by 9-month-old infants during non-symbolic arithmetic, whereby they overestimate the outcomes to addition problems, and underestimate the outcomes to subtraction problems. Recent evidence has shown that this effect extends to ordering operations for size-based sequences in 12-month-olds. Here we provide evidence that OM occurs for ordering operations involving numerical sequences containing multiple quantity cues, but not size-based sequences, already at 4 months of age. Infants were tested in an ordinal task in which they detected and represented increasing or decreasing variations in physical and/or numerical size, and then responded to ordinal sequences that exhibited greater or lesser sizes/numerosities, thus following or violating the OM generated during habituation. Results showed that OM was absent during size ordering (Experiment 1), but was present when infants ordered arrays of discrete elements varying on numerical and non-numerical dimensions, if both number and continuous magnitudes were available cues to discriminate between with-OM and against-OM sequences during test trials (Experiments 2 vs. 3). The presence of momentum for ordering number only when provided with multiple cues of magnitude changes suggests that OM is a complex phenomenon that blends multiple representations of magnitude early in infancy.

There has been compelling evidence favoring the idea that human adults similarly represent number and time along a horizontal mental number line (MNL) and mental time line (MTL), respectively. Yet, analogies drawn between the MNL and MTL have been challenged by recent studies suggesting that adults' representations of number and time arise from different spatial frames of reference; whereas the MNL relies on both hand-centered and object-centered coordinates, the MTL appears to be exclusively anchored on object-centered coordinates. To directly test this possibility, here we explored the extent to which visual feedback and proprioceptive feedback affect children's performance in a Number Comparison task (Experiment 1) and a Time Comparison task (Experiment 2), in which participants needed to associate a lateralized key with numerical and temporal words, respectively. Children (5- and 6-year-olds) performed the task with their hands either uncrossed or crossed over the body midline (i.e., manipulation of proprioceptive feedback) and with either visual control over their hands allowed or precluded under blindfolds (i.e., manipulation of visual feedback). Results showed that children were facilitated in associating smaller/larger numbers with the left/right side of the external space, but only when hands were uncrossed and visual feedback was available. On the contrary, blindfolding and crossing their hands over the midline did not affect spatial time mapping, with 6-year-olds showing facilitation in associating words referring to the past/future with the left/right side of the external space irrespective of visual and proprioceptive feedback. This same effect was also present in 5-year-olds despite their difficulty in performing the Time Comparison task. Together, these findings show, for the first time, that-just like adults-young children (a) map temporal events onto space in a rightward direction as they do for numbers and (b) anchor their spatial representation of time and numbers to different spatial frames of reference.

The human tactile system is known to discriminate different types of touches, one of these termed & lsquo;affective touch & rsquo;, is mainly mediated by slow conducting tactile afferents (CT fibres), which are preferentially activated by slow and gentle strokes. Human infants experience self-generated tactile stimulation during prena-tal life, and they receive a large amount of affectionate touches by their caregivers from birth. This early and extended experience with tactile stimulation may likely make infants particularly sensitive to affective touch, and increasing evidence shows that this may indeed be the case. However, infants commonly experience affective touch in the context of social interactions with familiar adults (e.g., while looking at their caregiver), and recent evidence suggests that this helps them assigning affiliative and communicative meaning to the touch they are perceiving. Here we investigated the presence of visual-tactile interactions in 4 & ndash;5-month-old infants & rsquo; physiolog-ical (i.e., skin conductance) and behavioural (i.e., visual looking times) responses to visual and tactile stimulation of affective/social nature when the sources of both stimulation are not familiar to the infant. To explore whether the modulation of physiological arousal elicited by the socially-relevant bimodal stimulation is specific to infants or extends into adulthood, we also tested a group of adults. Infants (N = 25) and adults (N = 25) were stimulated on their forearm through slow stroking (i.e. affective touch) or tapping (i.e. non-affective touch) during the obser-vation of dynamic images of socially-relevant (i.e., an unfamiliar face) and non-socially-relevant (i.e., a house) stimuli. We found that the simultaneous presentation of socially-relevant visual-tactile stimuli significantly decreased infants & rsquo; & ndash; but not the adults & rsquo; & ndash; electrodermal response, suggesting that infants easily integrate low-level properties of affective touch with socially salient visual information, and that social experience may tune and change sensitivity to affective touch across the life-span.

When adding or subtracting quantities, adults tend to overestimate addition outcomes and underestimate subtraction outcomes. They also shift visuospatial attention to the right when adding and to the left when subtracting. These operational momentum phenomena are thought to reflect an underlying representation in which small magnitudes are associated with the left side of space and large magnitudes with the right side of space. Currently, there is limited research on operational momentum in early childhood or for operations other than addition and subtraction. The current study tested whether English-speaking 3- and 4-year-old children and college-aged adults exhibit operational momentum when ordering quantities. Participants were presented with two experimental blocks. In one block of trials, they were tasked with choosing the same quantity they had previously seen three times; in the other block, they were asked to generate the next quantity in a doubling sequence composed of three ascending quantities. A bias to shift attention to the right after an ascending operation was found in both age groups, and a bias to overestimate the next sequential quantity during an ascending ordering operation was found in adults under conditions of uncertainty. These data suggest that, for children, the spatial biases during operating are more pronounced than the mis-estimation biases. These findings highlight the spatial underpinnings of operational momentum and suggest that both very young children and adults conceptualize quantity along a horizontal continuum during ordering operations, even before formal schooling.

The ability to discriminate social signals from faces is a fundamental component of human social interactions whose developmental origins are still debated. In this study, 5-year-old (N=29) and 7-year-old children (N=31) and adults (N=34) made perceptual similarity and trustworthiness judgments on a set of female faces varying in level of expressed trustworthiness. All groups represented perceived similarity of the faces as a function of trustworthiness intensity, but such representation becomes more fine-grained with development. Moreover, 5-year-olds' accuracy in choosing the more trustworthy face in a pair varied as a function of children's score at the Test of Emotion Comprehension, suggesting that the ability to perform face-to-trait inferences is related to the development of emotional understanding.

Early facial experience provided by the infant's social environment is known to shape face processing abilities, which narrow during the first year of life towards adult human faces of the most frequently encountered ethnic groups. Here we explored the hypothesis that natural variability in facial input may delay neural commitment to face processing by testing the impact of early natural experience with siblings on infants' brain responses. Event-Related Potentials (ERPs) evoked by upright and inverted adult and child faces were compared in two groups of 10-month-old infants with (N = 21) and without (N = 22) a child sibling. In first-born infants, P1 ERP component showed specificity to upright adult faces that carried over to the subsequent N290 and P400 components. In infants with siblings no inversion effects were observed. Results are discussed in the context of evidence from the language domain, showing that neural commitment to phonetic contrasts emerges later in bilinguals than in monolinguals, and that this delay facilitates subsequent learning of previously unencountered sounds of new languages.

One of the most important aspects of social interactions concerns the ability to discern social signals conveyed by other people. We know that adults and pre-schoolers easily distinguish between fine-grained differences in the level of trustworthiness expressed by faces. Nevertheless, only a few studies investigated the sensitivity to social signals of trustworthiness in infancy (Jessen & Grossmann, 2016; Jessen & Grossmann, 2017). By using computer-generated faces of male identities, these studies found no evidence of neural discrimination between trustworthy and untrustworthy faces, although both face types were discriminated from neutral faces. In this study, we aimed at investigating whether, at the age of 6 months, infants are able to discern between trustworthy and untrustworthy faces of truthful female identities. Infants were administered with a Fast-Periodic Visual Stimulation (FPVS) task, where two face identities were presented at a rate of 6 Hz (Baseline) following an Oddball paradigm. Every 1.2 Hz (Oddball), the trustworthiness level changed (a trustworthy face every 4 untrustworthy faces, or vice versa, in a counterbalanced order). Preliminary analyses show significant Signal-to-Noise Ratios (SNRs) at 6 Hz in occipital regions. More importantly, significant SNRs at 1.2 Hz were found in right occipital and right occipito-temporal regions. These results suggest that at 6 months infants are able to discriminate between different levels of trustworthiness, and that this discrimination takes place in brain areas known to play an important role in face discrimination. Future studies should investigate how fine-grained this sensitivity is, and how brain sensitivity is related to behavioural responses.

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure.