Effects of multimodal synchrony on infant attention and heart rate during events with social and nonsocial stimuli

Plasticity in older infants' perception of phonetic contrasts: The role of selective attention in context

Developmental plasticity refers to conditions and circumstances that increase phenotypic variability. In infancy, plasticity expands and contracts depending on domains of functioning, developmental history, and timing. In terms of language processing, infants attend to and discriminate both native and non-native phonetic contrasts, but selectively attune to their native phonemes by the end of the first postnatal year. However, relevant studies have excluded factors regarded as promoters of attention such as infant-directed (ID) speech, synchronous multimodal presentations, and female speakers. Here we investigated whether English-learning 11-month-olds would discriminate a non-native phonetic contrast while manipulating these factors. Results showed significant discrimination of the non-native contrast, regardless of speech register, provided that they were presented by a dynamic female speaker. Interestingly, when a static object or a dynamic male ID speaker replaced the female, no significant discrimination was found. These results show infants to be capable of discriminating non-native phonetic contrasts in an enhanced context at an age when they have been characterized as not being able to do so. Synchronized, multimodal information from female speakers allowed infants to perceive difficult non-native phonemes, highlighting the importance of an ecologically valid context for studying speech perception and language learning in early development.

Olfactory-to-visual facilitation in the infant brain declines gradually from 4 to 12 months

During infancy, intersensory facilitation declines gradually as unisensory perception develops. However, this trade-off was mainly investigated using audiovisual stimulations. Here, fifty 4- to 12-month-old infants (26 females, predominately White) were tested in 2017-2020 to determine whether the facilitating effect of their mother's body odor on neural face categorization, as previously observed at 4 months, decreases with age. In a baseline odor context, the results revealed a face-selective electroencephalographic response that increases and changes qualitatively between 4 and 12 months, marking improved face categorization. At the same time, the benefit of adding maternal odor fades with age (R2 = .31), indicating an inverse relation with the amplitude of the visual response, and generalizing to olfactory-visual interactions previous evidence from the audiovisual domain.

Synchrony perception across senses: A systematic review of temporal binding window changes from infancy to adolescence in typical and atypical development

Sensory integration is increasingly acknowledged as being crucial for the development of cognitive and social abilities. However, its developmental trajectory is still little understood. This systematic review delves into the topic by investigating the literature about the developmental changes from infancy through adolescence of the Temporal Binding Window (TBW) - the epoch of time within which sensory inputs are perceived as simultaneous and therefore integrated. Following comprehensive searches across PubMed, Elsevier, and PsycInfo databases, only experimental, behavioral, English-language, peer-reviewed studies on multisensory temporal processing in 0-17-year-olds have been included. Non-behavioral, non-multisensory, and non-human studies have been excluded as those that did not directly focus on the TBW. The selection process was independently performed by two Authors. The 39 selected studies involved 2859 participants in total. Findings indicate a predisposition towards cross-modal asynchrony sensitivity and a composite, still unclear, developmental trajectory, with atypical development associated to increased asynchrony tolerance. These results highlight the need for consistent and thorough research into TBW development to inform potential interventions.

Heart-to-heart: infant heart rate at 3 months is linked to infant-directed speech, mother-infant interaction, and later language outcomes

Introduction

Previous studies underscore the importance of speech input, particularly infant-directed speech (IDS) during one-on-one (1:1) parent-infant interaction, for child language development. We hypothesize that infants' attention to speech input, specifically IDS, supports language acquisition. In infants, attention and orienting responses are associated with heart rate deceleration. We examined whether individual differences in infants' heart rate measured during 1:1 mother-infant interaction is related to speech input and later language development scores in a longitudinal study.

Methods

Using a sample of 31 3-month-olds, we assessed infant heart rate during mother-infant face-to-face interaction in a laboratory setting. Multiple measures of speech input were gathered at 3 months of age during naturally occurring interactions at home using the Language ENvironment Analysis (LENA) system. Language outcome measures were assessed in the same children at 30 months of age using the MacArthur-Bates Communicative Development Inventory (CDI).

Results

Two novel findings emerged. First, we found that higher maternal IDS in a 1:1 context at home, as well as more mother-infant conversational turns at home, are associated with a lower heart rate measured during mother-infant social interaction in the laboratory. Second, we found significant associations between infant heart rate during mother-infant interaction in the laboratory at 3 months and prospective language development (CDI scores) at 30 months of age.

Discussion

Considering the current results in conjunction with other converging theoretical and neuroscientific data, we argue that high IDS input in the context of 1:1 social interaction increases infants' attention to speech and that infants' attention to speech in early development fosters their prospective language growth.

Infant sustained attention differs by context and social content in the first 2 years of life

Sustained attention (SA) is an endogenous form of attention that emerges in infancy and reflects cognitive engagement and processing. SA is critical for learning and has been measured using different methods during screen-based and interactive contexts involving social and nonsocial stimuli. How SA differs by measurement method, context, and stimuli across development in infancy is not fully understood. This 2-year longitudinal study examines attention using one measure of overall looking behavior and three measures of SA-mean look duration, percent time in heart rate-defined SA, and heart rate change during SA-in N = 53 infants from 1 to 24 months across four unique task conditions: social videos, nonsocial videos, social interactions (face-to-face play), and nonsocial interactions (toy engagement). Results suggest that developmental changes in attention differ by measurement method, task context (screen or interaction), and task stimulus (social or nonsocial). During social interactions, overall looking and look durations declined after age 3-4 months, whereas heart rate-defined attention measures remained stable. All SA measures were greater for videos than for live interaction conditions throughout the first 6 months, but SA to social and nonsocial stimuli within each task context were equivalent. In the second year of life, SA measured with look durations was greater for social videos compared to other conditions, heart rate-defined SA was greater for social videos compared to nonsocial interactions, and heart rate change during SA was similar across conditions. Together, these results suggest that different measures of attention to social and nonsocial stimuli may reflect unique developmental processes and are important to compare and consider together, particularly when using infant attention as a marker of typical or atypical development. RESEARCH HIGHLIGHTS: Attention measure, context, and social content uniquely differentiate developmental trajectories of attention in the first 2 years of life. Overall looking to caregivers during dyadic social interactions declines significantly from 4 to 6 months of age while sustained attention (SA) to caregivers remains stable. Heart rate-defined SA generally differentiates stimulus context where infants show greater SA while watching videos than while engaging with toys.

Early development of saliency-driven attention through object manipulation

In the first years of life, infants progressively develop attention selection skills to gather information from visually clustered environments. As young as newborns, infants are sensitive to the distinguished differences in color, orientation, and luminance, which are the components of visual saliency. However, we know little about how saliency-driven attention emerges and develops socially through everyday free-viewing experiences. The present work assessed the saliency change in infants' egocentric scenes and investigated the impacts of manual engagements on infant object looking in the interactive context of object play. Thirty parent-infant dyads, including infants in two age groups (younger: 3- to 6-month-old; older: 9- to 12-month-old), completed a brief session of object play. Infants' looking behaviors were recorded by the head-mounted eye-tracking gear, and both parents' and infants' manual actions on objects were annotated separately for analyses. The present findings revealed distinct attention mechanisms that underlie the hand-eye coordination between parents and infants and within infants during object play: younger infants are predominantly biased toward the characteristics of the visual saliency accompanying the parent's handled actions on the objects; on the other hand, older infants gradually employed more attention to the object, regardless of the saliency in view, as they gained more self-generated manual actions. Taken together, the present work highlights the tight coordination between visual experiences and sensorimotor competence and proposes a novel dyadic pathway to sustained attention that social sensitivity to parents' hands emerges through saliency-driven attention, preparing infants to focus, follow, and steadily track moving targets in free-flow viewing activities.

Effects of English versus Spanish language exposure on basic multisensory attention skills across 3 to 36 months of age

Recent research has demonstrated that individual differences in infant attention to faces and voices of women speaking predict language outcomes in childhood. These findings have been generated using two new audiovisual attention assessments appropriate for infants and young children, the Multisensory Attention Assessment Protocol (MAAP) and the Intersensory Processing Efficiency Protocol (IPEP). The MAAP and IPEP assess three basic attention skills (sustaining attention, shifting/disengaging, intersensory matching), as well as distractibility, deployed in the context of naturalistic audiovisual social (women speaking English) and nonsocial events (objects impacting a surface). Might children with differential exposure to Spanish versus English show different patterns of attention to social events on these protocols as a function of language familiarity? We addressed this question in several ways using children (n = 81 dual-language learners; n = 23 monolingual-language learners) from South Florida, tested longitudinally across 3-36 months. Surprisingly, results indicated no significant English language advantage on any attention measure for children from monolingual English versus dual English-Spanish language environments. Second, for dual-language learners, exposure to English changed across age, decreasing slightly from 3-12 months and then increasing considerably by 36 months. Furthermore, for dual-language learners, structural equation modeling analyses revealed no English language advantage on the MAAP or IPEP as a function of degree of English language exposure. The few relations found were in the direction of greater performance for children with greater Spanish exposure. Together, findings indicate no English language advantage for basic multisensory attention skills assessed by the MAAP or IPEP between the ages of 3 to 36 months. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Intersensory redundancy impedes face recognition in 12-month-old infants

This study examined the role of intersensory redundancy on 12-month-old infants' attention to and processing of face stimuli. Two experiments were conducted. In Experiment 1, 72 12-month-olds were tested using an online platform called Lookit. Infants were familiarized with two videos of an actor reciting a children's story presented simultaneously. A soundtrack either matched one of the videos (experimental condition) or neither of the videos (control condition). Visual-paired comparison (VPC) trials were completed to measure looking preferences for the faces presented synchronously and asynchronously during familiarization and for novel faces. Neither group displayed looking preferences during the VPC trials. It is possible that the complexity of the familiarization phase made the modality-specific face properties (i.e., facial characteristics and configuration) difficult to process. In Experiment 2, 56 12-month-old infants were familiarized with the video of only one actor presented either synchronously or asynchronously with the soundtrack. Following familiarization, participants completed a VPC procedure including the familiar face and a novel face. Results from Experiment 2 showed that infants in the synchronous condition paid more attention during familiarization than infants in the asynchronous condition. Infants in the asynchronous condition demonstrated recognition of the familiar face. These findings suggest that the competing face stimuli in the Experiment 1 were too complex for the facial characteristics to be processed. The procedure in Experiment 2 led to increased processing of the face in the asynchronous presentation. These results indicate that intersensory redundancy in the presentation of synchronous audiovisual faces is very salient, discouraging the processing of modality-specific visual properties. This research contributes to the understanding of face processing in multimodal contexts, which have been understudied, although a great deal of naturalistic face exposure occurs multimodally.

The role of task difficulty in directing selective attention in bobwhite quail (Colinus virginianus) neonates: A developmental test of the intersensory redundancy hypothesis

The dynamics of selective attention necessarily influences the course of early perceptual development. The intersensory redundancy hypothesis proposes that in early development information presented redundantly across two or more senses selectively recruits attention to the amodal properties of an object or event. In contrast, information presented to a single sense enhances attention to modality-specific properties. The present study assessed the second of these predictions in neonatal bobwhite quail (Colinus virginianus), with a focus on the role of task difficulty in directing selective attention. In Experiment 1, we exposed quail chicks to unimodal auditory, nonredundant audiovisual, or redundant audiovisual presentations of a bobwhite maternal call paired with a pulsing light for 10 min/h on the day following hatching. Chicks were subsequently individually tested 24 h later for their unimodal auditory preference between the familiarized maternal call and the same call with pitch altered by two steps. Chicks from all experimental groups preferred the familiarized maternal call over the altered maternal call. In Experiment 2, we repeated the exposure conditions of Experiment 1, but presented a more difficult task by narrowing the pitch range between the two maternal calls during testing. Chicks in the unimodal auditory and nonredundant audiovisual conditions preferred the familiarized call, whereas chicks in the redundant audiovisual exposure group showed no detection of the pitch change. Our results indicate that early discrimination of pitch change is disrupted by intersensory redundancy under difficult but not easy task conditions. These findings, along with findings from human infants, highlight the role of task difficulty in shifting attentional selectivity and underscore the dynamic nature of neonatal attentional salience hierarchies.

Preterm birth and neonatal white matter microstructure in in-vivo reconstructed fiber tracts among audiovisual integration brain regions

Individuals born preterm are at risk of developing a variety of sequelae. Audiovisual integration (AVI) has received little attention despite its facilitating role in the development of socio-cognitive abilities. The present study assessed the association between prematurity and in-vivo reconstructed fiber bundles among brain regions relevant for AVI. We retrieved data from 63 preterm neonates enrolled in the Developing Human Connectome Project (http://www.developingconnectome.org/) and matched them with 63 term-born neonates from the same study by means of propensity score matching. We performed probabilistic tractography, DTI and NODDI analysis on the traced fibers. We found that specific DTI and NODDI metrics are significantly associated with prematurity in neonates matched for postmenstrual age at scan. We investigated the spatial overlap and developmental order of the reconstructed tractograms between preterm and full-term neonates. Permutation-based analysis revealed significant differences in dice similarity coefficients and developmental order between preterm and full term neonates at the group level. Contrarily, no group differences in the amount of interindividual variability of DTI and NODDI metrics were observed. We conclude that microstructural detriment in the reconstructed fiber bundles along with developmental and morphological differences are likely to contribute to disadvantages in AVI in preterm individuals.

Audiovisual synchrony detection for fluent speech in early childhood: An eye-tracking study

During childhood, the ability to detect audiovisual synchrony gradually sharpens for simple stimuli such as flashbeeps and single syllables. However, little is known about how children perceive synchrony for natural and continuous speech. This study investigated young children's gaze patterns while they were watching movies of two identical speakers telling stories side by side. Only one speaker's lip movements matched the voices and the other one either led or lagged behind the soundtrack by 600 ms. Children aged 3-6 years (n = 94, 52.13% males) showed an overall preference for the synchronous speaker, with no age-related changes in synchrony-detection sensitivity as indicated by similar gaze patterns across ages. However, viewing time to the synchronous speech was significantly longer in the auditory-leading (AL) condition compared with that in the visual-leading (VL) condition, suggesting asymmetric sensitivities for AL versus VL asynchrony have already been established in early childhood. When further examining gaze patterns on dynamic faces, we found that more attention focused on the mouth region was an adaptive strategy to read visual speech signals and thus associated with increased viewing time of the synchronous videos. Attention to detail, one dimension of autistic traits featured by local processing, has been found to be correlated with worse performances in speech synchrony processing. These findings extended previous research by showing the development of speech synchrony perception in young children, and may have implications for clinical populations (e.g., autism) with impaired multisensory integration.

Fiber tracing and microstructural characterization among audiovisual integration brain regions in neonates compared with young adults

Audiovisual integration has been related with cognitive-processing and behavioral advantages, as well as with various socio-cognitive disorders. While some studies have identified brain regions instantiating this ability shortly after birth, little is known about the structural pathways connecting them. The goal of the present study was to reconstruct fiber tracts linking AVI regions in the newborn in-vivo brain and assess their adult-likeness by comparing them with analogous fiber tracts of young adults. We performed probabilistic tractography and compared connective probabilities between a sample of term-born neonates (N = 311; the Developing Human Connectome Project (dHCP, http://www.developingconnectome.org) and young adults (N = 311 The Human Connectome Project; https://www.humanconnectome.org/) by means of a classification algorithm. Furthermore, we computed Dice coefficients to assess between-group spatial similarity of the reconstructed fibers and used diffusion metrics to characterize neonates' AVI brain network in terms of microstructural properties, interhemispheric differences and the association with perinatal covariates and biological sex. Overall, our results indicate that the AVI fiber bundles were successfully reconstructed in a vast majority of neonates, similarly to adults. Connective probability distributional similarities and spatial overlaps of AVI fibers between the two groups differed across the reconstructed fibers. There was a rank-order correspondence of the fibers' connective strengths across the groups. Additionally, the study revealed patterns of diffusion metrics in line with early white matter developmental trajectories and a developmental advantage for females. Altogether, these findings deliver evidence of meaningful structural connections among AVI regions in the newborn in-vivo brain.

Age-Related Dynamics of Crossmodal Priming

<p>The study is aimed at studying at determining the temporal dynamics of crossmodal priming in preschool children. The study involved 60 children aged 4 to 6 years (M = 5.6; SD = 1.2) and 20 adult subjects aged 17 to 23 years (M = 20.4; SD = 2.6). The priming paradigm was used as a research model. In this study, we determined the influence of a priori visual stimulation on the speed and accuracy of identification of test sounds, depending on the congruence of their combination with visual objects and the interval between the test and prime stimuli. In the course of the study, it was found that in 4-year-old children, a priori visual information leads to a decrease in the accuracy and speed of reaction to test sound stimuli - a negative priming effect. The magnitude of the negative priming effect decreases with an increase in the interval between prime and test stimuli. In 5-year-old children, the number of errors increases only when incongruent combinations of stimuli are presented - a negative priming effect. On the contrary, the reaction time decreases only in congruent trials with when the test stimulus is delayed relative to the prime by 150-500 ms &mdash; a positive priming effect. In 6-year-old children and adults, the accuracy of the reaction does not change, and the reaction rate significantly increases in congruent trials positive priming effect) and decreases in incongruent trials (negative priming effect). The observed dynamics of changes in the interaction of sound and visual stimulation testifies to the formation of mechanisms of attention and multisensory integration in preschool children.</p>

A survey on the attitudes of parents with young children on in-home monitoring technologies and study designs for infant research

Remote in-home infant monitoring technologies hold great promise for increasing the scalability and safety of infant research (including in regard to the current Covid-19 pandemic), but remain rarely employed. These technologies hold a number of fundamental challenges and ethical concerns that need addressing to aid the success of this fast-growing field. In particular, the responsible development of such technologies requires caregiver input. We conducted a survey of the opinions of 410 caregivers on the viability, privacy and data access of remote in-home monitoring technologies and study designs. Infant-friendly wearable devices (such as sensing body suits) were viewed favourably. Caregivers were marginally more likely to accept video and audio recording in the home if data was anonymised (through automated processing) at point of collection, particularly when observations were lengthy. Caregivers were more open to international data sharing for anonymous data. Caregivers were interested in viewing all types of data, but were particularly keen to access video and audio recordings for censoring purposes (i.e., to delete data segments). Taken together, our results indicate generally positive attitudes to remote in-home monitoring technologies and studies for infant research but highlight specific considerations such as safety, privacy and family practicalities (e.g. multiple caregivers, visitors and varying schedules) that must be taken into account when developing future studies.

Effects of motion and audio-visual redundancy on upright and inverted face and feature preferences in 4-13-month old pre- and full-term NICU graduates

NICU infants are reported to have diminished social orientation and increased risk of socio-communicative disorders. In this eye tracking study, we used a preference for upright compared to inverted faces as a gauge of social interest in high medical risk full- and pre-term NICU infants. We examined the effects of facial motion and audio-visual redundancy on face and eye/mouth preferences across the first year. Upright and inverted baby faces were simultaneously presented in a paired-preference paradigm with motion and synchronized vocalization varied. NICU risk factors including birth weight, sex, and degree of CNS injury were examined. Overall, infants preferred the more socially salient upright faces, making this the first report, to our knowledge, of an upright compared to inverted face preference among high medical risk NICU infants. Infants with abnormalities on cranial ultrasound displayed lower social interest, i.e. less of a preferential interest in upright faces, when viewing static faces. However, motion selectively increased their upright face looking time to a level equal that of infants in other CNS injury groups. We also observed an age-related sex effect suggesting higher risk in NICU males. Females increased their attention to the mouth in upright faces across the first year, especially between 7-10 months, but males did not. Although vocalization increased diffuse attention toward the screen, contrary to our predictions, there was no evidence that the audio-visual redundancy embodied in a vocalizing face focused additional attention on upright faces or mouths. This unexpected result may suggest a vulnerability in response to talking faces among NICU infants that could potentially affect later verbal and socio-communicative development.

Audiovisual temporal integration: Cognitive processing, neural mechanisms, developmental trajectory and potential interventions

To integrate auditory and visual signals into a unified percept, the paired stimuli must co-occur within a limited time window known as the Temporal Binding Window (TBW). The width of the TBW, a proxy of audiovisual temporal integration ability, has been found to be correlated with higher-order cognitive and social functions. A comprehensive review of studies investigating audiovisual TBW reveals several findings: (1) a wide range of top-down processes and bottom-up features can modulate the width of the TBW, facilitating adaptation to the changing and multisensory external environment; (2) a large-scale brain network works in coordination to ensure successful detection of audiovisual (a)synchrony; (3) developmentally, audiovisual TBW follows a U-shaped pattern across the lifespan, with a protracted developmental course into late adolescence and rebounding in size again in late life; (4) an enlarged TBW is characteristic of a number of neurodevelopmental disorders; and (5) the TBW is highly flexible via perceptual and musical training. Interventions targeting the TBW may be able to improve multisensory function and ameliorate social communicative symptoms in clinical populations.