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Evidence on newborns’ discrimination of emotional facial expressions is scarce, and the question of what is the nature of the visual information that newborns rely on to perform such discrimination remains open. Here, we manipulated the spatial frequency (SF) content of the stimuli by selectively removing low spatial frequency (LSF) and high spatial frequency bands using newborn-appropriate cutoffs to investigate what information newborns use when preferring and discriminating between dynamic displays showing happy and fearful expressions unfolding over time. Using a preferential looking paradigm, in Study 1 (N = 63, 59% females, 92% White), we showed that newborns looked longer to happy over fearful expressions in unfiltered (broad spatial frequency) and high-pass (high spatial frequency.0.6 cycles per degree [cpd]) faces but not in low-pass (LSF, 0.5 cpd) faces. In Study 2 (N = 22, 59% females, 91% White), newborns tested in a visual habituation paradigm showed successful discrimination of the two LSF emotions. Results show that newborns can discriminate between dynamic images of happy and fearful facial expressions containing either extreme low SF (,0.5 cpd) information or higher SF (.0.6 cpd) bandwidth. Their preference for the happy expression was present for intact and high-pass filtered faces but not for low-pass faces. This SF effect is tentatively driven by an enhancement of attentional response to the LSF fearful face, whereas the response to the happy face is unaffected by the SF manipulation.

Background: Rule learning (RL) is the ability to extract and generalize higher-order repetition-based structures. Children with Developmental Dyslexia (DD) often report difficulties in learning complex regularities in sequential stimuli, which might be due to the complexity of the rule to be learned. Learning high-order repetition-based rules represents a building block for the development of language skills. Aims: This study investigates the ability to extract and generalize simple, repetition-based visual rules (e.g., ABA) in 8–11-year-old children without (TD) and with a diagnosis of Development Dyslexia (DD) and its relationship with language and reading skills. Method: Using a forced-choice paradigm, children were first exposed to a visual sequence containing a repetition-based rule (e.g., ABA) and were then asked to recognize familiar and novel rules generated by new visual elements. Standardized language and reading tests were also administered to both groups. Results: The accuracy in recognizing rules was above chance for both groups, even though DD children were less accurate than TD children, suggesting a less efficient RL mechanism in the DD group. Moreover, visual RL was positively correlated with both language and reading skills. Conclusion: These results further confirm the crucial role of RL in the acquisition of linguistic skills and mastering reading abilities.

Il ritmo è una componente intrinseca del comportamento umano e pervade il nostro ambiente fin dalla vita intrauterina. Questa tesi di dottorato ha esplorato come il nostro cervello sfrutta il ritmo per ottimizzare le interazioni con l'ambiente nelle prime fasi della vita, testando l'effetto del ritmo su due funzioni motorie e cognitive dei neonati: la Suzione Non-Nutritiva (SNN), un comportamento ritmico presente già in utero, e l'attenzione visiva, che negli adulti sappiamo esse modulata dal ritmo. Nove studi hanno affrontato 3 domande principali: 1) Il ritmo modula la SNN alla nascita e l'orientamento dell'attenzione visuospaziale alla nascita e a 2 mesi? 2) L'arricchimento ritmico prenatale modula gli effetti del ritmo sulla SNN e sull'attenzione visuospaziale alla nascita e a 2 mesi? 3) Il ritmo influenza la percezione visiva negli adulti e nei neonati? Lo Studio 1 ha indagato l’effetto della stimolazione acustica ritmica vs. non-ritmica sulla SNN. I risultati mostrano che la frequenza della SNN diminuisce durante la presentazione del suono non-ritmico, che ha quindi un effetto inibitorio sulla SNN dei neonati. Lo Studio 2 ha esplorato l'effetto della stimolazione ritmica prenatale sulla SNN e sulla capacità di adattare il proprio ritmo di suzione a stimolazioni ritmiche esterne. I risultati suggeriscono che 1) l'esposizione arricchita al ritmo aumenta la frequenza della SNN dopo la nascita e 2) la risposta inibitoria ai suoni non-ritmici varia in funzione della quantità di stimolazione ritmica prenatale ricevuta. Gli Studi 3a-3b hanno indagato l'effetto del ritmo sull'attenzione visuospaziale, testando la capacità di disancorare l'attenzione visiva da uno stimolo centrale (S1) ritmico vs. non-ritmico alla nascita e a 2 mesi. I risultati mostrano che a 2 mesi, ma non alla nascita, i neonati sono più lenti a disancorare l'attenzione visiva da S1 non-ritmico rispetto a quando S1 è ritmico o statico. Lo Studio 3c è stato condotto per esaminare l'eventuale i, Rhythm, the recurrence of temporal structures over time, is an inherent part of human behaviour and pervades our environment since intrauterine life. This doctoral thesis explored how our brain harnesses rhythmic cues to optimise interactions with the environment in the earliest stages of life by testing the effect of rhythm on two infants’ motor and cognitive functions: Non-Nutritive Sucking (NNS), which is an endogenous rhythmic behaviour available in utero, and visual attention, which in adults is known to be modulated by rhythmic cues. Nine studies addressed 3 main questions: 1) Does rhythmic stimulation modulate NNS at birth and the orienting of visuospatial attention at birth and 2 months? 2) Does prenatal rhythmic enrichment modulate the effects of rhythm on NNS and visuospatial attention at birth and 2 months? 3) Does rhythm affect visual perception in adults and infants? Study 1 investigated the impact of rhythmic vs. non-rhythmic sounds on NNS. Results showed that NNS rate was lower when the non-rhythmic sound was presented contingent upon sucking than when the rhythmic sound or no sound was presented. These findings suggest that non-rhythmic acoustic stimulation produces an inhibitory effect on newborns’ NNS behaviour. Study 2 explored the effect of prenatal rhythmic stimulation on NNS and the ability to modulate the NNS sucking rhythm in response to external rhythmic stimulation. Results showed that 1) the enriched exposure to rhythm enhanced the NNS rate and pressure after birth, and 2) the inhibitory response to non-rhythmic sounds varied as a function of the amount of prenatal rhythmic stimulation. Studies 3a-3b investigated the effect of rhythm on visuospatial attention, testing the ability to disengage visual attention from a rhythmic vs. non-rhythmic central stimulus (S1) at birth and 2 months. Results showed that at 2 months, but not at birth, infants were slower in disengaging visual attention from a non-rhythmic S1 than when S1 was rhythmic or s

Data from 83,423 parent reports of temperament (surgency, negative affectivity, and regulatory capacity) in infants, toddlers, and children from 341 samples gathered in 59 countries were used to investigate the relations among culture, gender, and temperament. Between-nation differences in temperament were larger than those obtained in similar studies of adult personality, and most pronounced for negative affectivity. Nationlevel patterns of negative affectivity were consistent across infancy, toddlerhood, and childhood, and patterns of regulatory capacity were consistent between infancy and toddlerhood. Nations that previously reported high extraversion, high conscientiousness, and low neuroticism in adults were found to demonstrate high surgency in infants and children, and countries reporting lowadult openness and high adult neuroticism reported high temperamental negative affectivity. Negative affectivity was high in Southern Asia, Western Asia, and South America and low in Northern and Western Europe. Countries in which children were rated as high in negative affectivity had cultural orientations reflecting collectivism, high power distance, and short-term orientation. Surgency was high in Southeastern and Southern Asia and Southern Europe and low in Eastern Asian countries characterized by philosophies of long-term orientation. Low personal income was associated with high negative affectivity. Gender differences in temperament were largely consistent in direction with prior studies, revealing higher regulatory capacity in females than males and higher surgency in males than females, with these differences becoming more pronounced at later ages.

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.

Ordinality is a fundamental aspect of numerical cognition. However, preverbal infants’ ability to represent numerical order is poorly understood. In the present study we extended the evidence provided by Macchi Cassia, Picozzi, Girelli, and de Hevia (2012), showing that 4-month-old infants detect ordinal relationships within size-based sequences, to numerical sequences. In three experiments, we showed that at 4 months of age infants fail to represent increasing and decreasing numerical order when numerosities differ by a 1:2 ratio (Experiment 1), but they succeed when numerosities differ by a 1:3 ratio (Experiments 2 and 3). Critically, infants showed the same behavioral signature (i.e., asymmetry) described by Macchi Cassia et al. for discrimination of ordinal changes in area: they succeed at detecting increasing but not decreasing order (Experiments 2 and 3). These results support the idea of a common (or at least parallel) development of ordinal representation for the two quantitative dimensions of size and number. Moreover, the finding that the asymmetry signature, previously reported for size-based sequences, extends to numerosity, points to the existence of a common constraint in ordinal magnitude processing in the first months of life. The present findings are discussed in the context of possible evolutionary and developmental sources of the ordinal asymmetry, as well as their implication for other related cognitive abilities.

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.

In mammals, including humans, affective touch (AT) supports the establishment and maintenance of social connections and mitigates the effects of social conflict and ostracism. AT is used to describe slowly moving, low-forced mechanical stimulation that is frequently perceived as pleasant. In humans, AT has been addressed particularly for its role in promoting bonding and emotional regulation during early development; however, more recent studies have suggested that AT also preserves physical and emotional well-being in adulthood. Here, we investigated whether AT can buffer adults’ experience of negative emotions as reflected in their behavioral and physiological responses to emotionally arousing stimuli. Participants were stimulated on their forearms using AT or tapping (T) while they viewed a series of emotionally arousing and neutral images, and we measured their skin conductance response and their explicit rating of the images’ unpleasantness. We found that AT, but not T, reduced the arousal and perceived unpleasantness of the emotional stimuli but not the neutral ones, revealing the soothing role of AT in emotional contexts. The second aim of the study was to explore the possibility that AT might benefit some individuals more than others, according to their individual differences. To this aim, we assessed individuals’ empathy and sensory processing sensitivity, as well as their perception of AT itself. Results revealed that while empathy did not predict changes in emotional processing irrespective of tactile stimulation, individuals with higher sensitivity reported AT as less pleasant.We discuss the possible factors mediating the observed interindividual variability in AT perception.

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.

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.

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.

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.

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.

Adults present a large number of asymmetries in visuospatial behavior that are known to be supported by functional brain lateralization. Although there is evidence of lateralization for motor behavior and language processing in infancy, no study has explored visuospatial attention biases in the early stages of development. In this study, we tested for the presence of a leftward visuospatial bias (i.e., pseudoneglect) in 4- and 5-month-old infants using an adapted version of the line bisection task. Infants were trained to identify the center of a horizontal line (Experiment 1) while their eye gazes were monitored using a remote eyetracking procedure to measure their potential gazing error. Infants exhibited a robust pseudoneglect, gazing leftward with respect to the veridical midpoint of the horizontal line. To investigate whether infants’ pseudoneglect generalizes to any given object or is dependent on the horizontal dimension, in Experiment 2 we assessed infants’ gaze deployment in vertically oriented lines. No leftward bias was found, suggesting that early visuospatial attention biases in infancy are constrained by the orientation of the visual plane in which the information is organized. The interplay between biological and cultural factors that might contribute to the early establishment of the observed leftward bias in the allocation of visuospatial attention is discussed.

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.

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

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<.040). We interpreted these results as evidence of early preferential directional encoding strategies of serial order and its internal representation that are modulated by culture through infants’ passive exposure and/or active imitation of directionally relevant culturally-driven routines. To further explore this argument, we will present data on caregivers’ directional behaviors during sessions of joint reading and toy construction.

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.

Una componente fondamentale della competenza sociale degli esseri umani è l'abilità di estrarre rapidamente e in modo spontaneo i segnali sociali che provengono dal volto, quali per esempio i tratti emotivi e di affidabilità. Il fatto che le risposte a queste configurazioni facciali siano rapide e automatiche suggerisce come esse derivino dalla pressione evolutiva a rilevare segnali di pericolo per aumentare le possibilità di sopravvivenza. Tuttavia, le origini ontogenetiche di queste abilità sociali sono ancora oggetto di dibattito. La presente tesi di dottorato si pone l'obiettivo di indagare la natura dell’informazione visiva che media la discriminazione delle emozioni e/o la percezione dell'affidabilità dai volti utilizzando l'approccio del filtraggio spaziale, ossia la rimozione selettiva di bande di frequenze spaziali contenute nell'immagine. Nello specifico, l’elaborato comprende 5 studi volti a indagare (1) la natura dell'informazione visiva sui cui si basano i giudizi espliciti di affidabilità degli adulti (Studio 1) (2) se la percezione di affidabilità di adulti (Studio 2) e bambini (Studio 3) è generalizzata a volti di un'etnia differente dalla propria e la natura dell'informazione visiva coinvolta, (3) la natura dell'informazione visiva che determina la discriminazione neurale di affidabilità dai volti nei preverbali (Studio 4), e (4) la natura dell'informazione visiva su cui si basa la discriminazione visiva delle emozioni alla nascita (Studio 5a e 5b). I risultati dello Studio 1 mostrano che sebbene sia le informazioni visive globali, veicolate dalle frequenze spaziali basse, che le informazioni visive locali, veicolate dalle frequenze spaziali alte, sono sufficienti per discriminare tra livelli di affidabilità, l'informazione globale gioca un ruolo cruciale. Gli Studi 2 e 3 estendono le considerazioni sulla natura dell'informazione visiva coinvolta nella percezione di affidabilità a volti meno presenti nell'ambiente sociale dell'individuo, One fundamental component of humans' social competence is the ability to rapidly and spontaneously extrapolate facial cues of emotion and trustworthiness - i.e., whether others are likely to approach us friendly or hostilely. The fast and automatic nature of these responses to facial configurations has led to the claim that they derive from evolutionary pressure to detect signals of potential harm, and distinguish between friends or foes to enhance our chances of survival. However, the ontogenetic origins of these fundamental social skills are still debated. To explore this question, the studies reported in this doctoral dissertation investigated the nature of the visual information driving emotion discrimination and/or trustworthiness perception across the life span using the spatial filtering approach - i.e., the selective removal of portions of the spatial frequencies (SF) information contained in the image. Specifically, this doctoral dissertation includes 5 studies aimed at investigating (1) the nature of the visual information on which adults' explicit judgments of trustworthiness are based (Study 1), (2) whether trustworthiness perception in adults (Study 2) and children (Study 3) generalizes across face-race and/or the nature of the visual information on which trustworthiness judgments are based differs for more versus less familiar face categories, (3) the nature of the visual information that triggers neural discrimination of facial cues to trustworthiness in preverbal infants (Study 4), and (4) the nature of the visual information that mediates visual discrimination of emotional facial expressions at birth (Study 5a and 5b). Results of Study 1 showed that, although both global visual cues, conveyed by low-spatial frequency bands, and local visual cues, conveyed by high-spatial frequency bands, are sufficient to discriminate between levels of trustworthiness, the selective removal of global information negatively impacts trustworthiness perception. Study 2

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.

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 con-strained 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.

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.

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.