Space modulates cross-domain transfer of abstract rules in infants.

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.

Signatures of functional visuospatial asymmetries in early infancy.

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 eye-tracking 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.

Infants' visual exploration strategies for adult and child faces.

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.

Electrophysiological Evidence of Space-Number Associations in 9-Month-Old Infants.

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 transfer across linguistic and visual modalities in 7-month-old infants.

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.

Age-Related Differences in Sensitivity to Facial Trustworthiness: Perceptual Representation and the Role of Emotional Development.

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.

Emotion in motion: Facial dynamics affect infants' neural processing of emotions.

Research investigating the early development of emotional processing has focused mainly on infants' perception of static facial emotional expressions, likely restricting the amount and type of information available to infants. In particular, the question of whether dynamic information in emotional facial expressions modulates infants' neural responses has been rarely investigated. The present study aimed to fill this gap by recording 7-month-olds' event-related potentials to static (Study 1) and dynamic (Study 2) happy, angry, and neutral faces. In Study 1, happy faces evoked a faster right-lateralized negative central (Nc) component compared to angry faces. In Study 2, both happy and angry faces elicited a larger right-lateralized Nc compared to neutral faces. Irrespective of stimulus dynamicity, a larger P400 to angry faces was associated with higher scores on the Negative Affect temperamental dimension. Overall, results suggest that 7-month-olds are sensitive to facial dynamics, which might play a role in shaping the neural processing of facial emotional expressions. Results also suggest that the amount of attentional resources infants allocate to angry expressions is associated to their temperamental traits. These findings represent a promising avenue for future studies exploring the neurobiological processes involved in perceiving emotional expressions using dynamic stimuli.

Perceptual narrowing towards adult faces is a cross-cultural phenomenon in infancy: a behavioral and near-infrared spectroscopy study with Japanese infants.

Recent data showed that, in Caucasian infants, perceptual narrowing occurs for own-race adult faces between 3 and 9 months of age, possibly as a consequence of the extensive amount of social and perceptual experience accumulated with caregivers and/or other adult individuals of the same race of the caregiver. The neural correlates of this developmental process remain unexplored, and it is currently unknown whether perceptual tuning towards adult faces can be extended to other cultures. To this end, in the current study we tested the ability of 3- and 9-month-old Japanese infants to discriminate among adult and infant Asian faces in a visual familiarization task (Experiment 1), and compared 9-month-olds' cerebral hemodynamic responses to adult and infant faces as measured by near-infrared spectroscopy (NIRS) (Experiment 2). Results showed that 3-month-olds exhibit above-chance discrimination of adult and infant faces, whereas 9-month-olds discriminate adult faces but not infant faces (Experiment 1). Moreover, adult faces, but not infant faces, induced significant increases in hemodynamic responses in the right temporal areas of 9-month-old infants. Overall, our data suggest that perceptual narrowing towards adult faces is a cross-cultural phenomenon occurring between 3 and 9 months of age, and translates by 9 months of age into a right-hemispheric specialization in the processing of adult faces.

Sibling experience modulates perceptual narrowing toward adult faces in the first year of life.

During the first year of life face discrimination abilities narrow toward adult human faces of the most frequently encountered ethnic group/s. Earlier studies showed that perceptual learning under laboratory-training protocols can modulate this narrowing process. Here we investigated whether natural experience acquired in everyday settings with an older sibling's face can shape the trajectory of perceptual narrowing towards adult faces. Using an infant-controlled habituation procedure we measured discrimination of adult (Experiment 1) and child faces (Experiment 2) in 3- and 9- month-old infants with and without a child sibling. Discrimination of adult faces was observed for infants at both ages, although accompanied by posthabituation preferences in opposite directions, whereas at both ages the discrimination of child faces critically depended on sibling experience. These results provide the first evidence that natural experience acquired with siblings affects the tuning properties of infant face representation.

Visual and proprioceptive feedback differently modulate the spatial representation of number and time in children.

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.

Infants' Visual Recognition of Pincer Grip Emerges Between 9 and 12 Months of Age.

The development of the ability to recognize the whole human body shape has long been investigated in infants, while less is known about their ability to recognize the shape of single body parts, and in particular their biomechanical constraints. This study aimed to explore whether 9- and 12-month-old infants have knowledge of a hand-grasping movement (i.e., pincer grip), being able to recognize violations of the hand's anatomical constraints during the observation of that movement. Using a preferential looking paradigm, we showed that 12-month-olds discriminate between biomechanically possible and impossible pincer grips, preferring the former over the latter (Experiment 1). This capacity begins to emerge by 9 months of age, modulated by infants' own sensorimotor experience with pincer grip (Experiment 2). Our findings indicate that the ability to visually discriminate between pincer grasps differing in their biomechanical properties develops between 9 and 12 months of age, and that experience with self-produced hand movements might help infants in building a representation of the hand that encompasses knowledge of the physical constraints of this body part.

Small on the left, large on the right: numbers orient visual attention onto space in preverbal infants.

Numbers are represented as ordered magnitudes along a spatially oriented number line. While culture and formal education modulate the direction of this number-space mapping, it is a matter of debate whether its emergence is entirely driven by cultural experience. By registering 8-9-month-old infants' eye movements, this study shows that numerical cues are critical in orienting infants' visual attention towards a peripheral region of space that is congruent with the number's relative position on a left-to-right oriented representational continuum. This finding provides the first direct evidence that, in humans, the association between numbers and oriented spatial codes occurs before the acquisition of symbols or exposure to formal education, suggesting that the number line is not merely a product of human invention.

Operational momentum and size ordering in preverbal infants.

Recent evidence has shown that, like adults and children, 9-month-old infants manifest an operational momentum (OM) effect during non-symbolic arithmetic, whereby they overestimate the outcomes to addition problems, and underestimate the outcomes to subtraction problems. Here we provide the first evidence that OM occurs for transformations of non-numerical magnitudes (i.e., spatial extent) during ordering operations. Twelve-month-old infants were tested in an ordinal task in which they detected and represented ascension or descension in physical size, and then responded to ordinal sequences that exhibited greater or lesser sizes. Infants displayed longer looking time to the size change whose direction violated the operational momentum experienced during habituation (i.e., the smaller sequence in the ascension condition and the larger sequence in the descension condition). The presence of momentum for ordering size during infancy suggests that continuous quantities are represented spatially during the first year of life.

The left perceptual bias for adult and infant faces in adults and 5-year-old children: face age matters.

A large number of studies have shown that adults rely more heavily on information conveyed by the left side of the face in judging emotional state, gender and identity. This phenomenon, called left perceptual bias (LPB), suggests a right hemisphere lateralization of face processing mechanisms. Although specialization of neural mechanisms for processing over-experienced face categories begins during the first year of life, little is known about the developmental trajectory of the LPB and whether or when the bias becomes selective for specific face categories as a result of experience. To address these questions we tested adults (Experiment 1) and 5-year-old children (Experiment 2) with null or limited experience with infants in an identity matching-to-sample task with chimeric adult and infant faces, for which both adults and children have been shown to manifest differential processing abilities. Results showed that 5-year-olds manifest a leftward bias selective for adult faces, and the magnitude of the bias is larger for adult compared to infant faces in adults. This evidence is in line with earlier demonstrations of a perceptual processing advantage for adult faces in adults and children and points to the role of experience in shaping neurocognitive specialization for face processing.

How race and age experiences shape young children's face processing abilities.

Despite recent advances in research on race and age biases, the question of how race and age experiences combine to affect young children's face perception remains unexplored. To fill this gap, the current study tested two ethnicities of 3-year-old children using a combined cross-race/cross-age design. Caucasian children with and without older siblings and Mainland Chinese children without older siblings were tested for their ability to discriminate adult and child Caucasian faces as well as adult and child Asian faces in both upright and inverted orientations. Children of both ethnicities manifested an own-race bias, which was confined to adult faces, and an adult face bias, which was confined to own-race faces. Likewise, sibling experience affected Caucasian children's processing of own-race child faces, but this effect did not generalize to other-race faces. Results suggest that race and age information are represented at the same hierarchical level in young children's memory.

Age-related face processing bias in infancy: evidence of perceptual narrowing for adult faces.

Recent data demonstrate a perceptual processing advantage for adult faces in both adults and young children, suggesting that face representation is shaped by visual experience accumulated with different face-age groups. As for species and race, this age bias may emerge during the first year of life as part of the general process of perceptual narrowing, given the extensive amount of social and perceptual experience accumulated with caregivers and/or other adult individuals. Using infant-controlled habituation and visual-paired comparison at test, two experiments were carried out to examine 3- and 9-month-olds' ability to discriminate within adult and infant faces. Results showed that, when they are provided with adequate time to visually compare the stimuli during test trials (Experiment 2), 3-month-olds exhibit above-chance discrimination of adult and infant faces. Instead, 9-month-olds discriminate adult faces but not infant faces (Experiments 1 and 2). Results provide the first evidence of age-related face processing biases in infancy, and show that by 9 months face representations tune to adult human faces.

The role of visual spatial frequencies in newborns' processing of dynamic facial expressions of emotion.

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. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Rules generalization in children with dyslexia.

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.

Touch me or touch me not: Emotion regulation by affective touch in human adults.

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. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Neural discrimination of facial cues associated with trustworthiness in adults and 6-month-old infants as revealed by fast periodic visual stimulation.

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. (PsycInfo Database Record (c) 2023 APA, all rights reserved).