Dr Nayeli Gonzalez-Gomez

Early childhood education and care (ECEC) settings faced significant disruption during the COVID-19 pandemic, compromising the continuity, stability, and quality of provision. Three years on from the first UK lockdown as pandemic-era preschoolers enter formal schooling, families, practitioners, and policymakers are concerned about the impact of the disruption on children’s cognitive and socioemotional development, especially those from socioeconomically disadvantaged backgrounds. Using parent-report data from 171 children aged between 5 and 23 months (M=15 months) in March – June 2020 (Spring 2020) living in the UK, we investigate whether previously attested positive associations between ECEC attendance and the development of language and executive functions was maintained as early years settings navigated operational challenges over the first full year of the pandemic. In response to concerns about ‘school readiness’, we analyse the relationship between ECEC attendance and children’s communication, problem-solving, and personal-social development. ECEC was associated with greater growth in receptive vocabulary over the 12-month period, regardless of children’s socioeconomic background. In children from less advantaged backgrounds, ECEC was also associated with greater growth in expressive vocabulary. Our data suggest a similarly positive association between ECEC attendance and the communication and problem-solving skills of children from lower socioeconomic (SES) backgrounds, and between ECEC and the personal-social development of all children. We found no effect of SES or ECEC attendance on growth of either of our measures of executive function. Overall, results suggest that ECEC had sustained learning benefits for young children growing up during the pandemic despite ongoing disruption to settings, and also had specific benefits for children from less affluent home environments. As children progress to primary school, we discuss the importance of adjusting the expectations placed on pandemic-era children, and adapting curricula and learning conditions to enable schools and families to make the most of learning opportunities.

Family history (FH) of autism and ADHD is not often considered during the recruitment process of developmental studies, despite high recurrence rates. We looked at the rate of autism or ADHD amongst family members of young children (9 to 46 months) in three UK-based samples (N=1055) recruited using different methods. The rate of FH-autism or FH-ADHD was 3-9% for diagnosed cases. The rate was highest in the sample recruited through an online participant pool, which also consisted of the most socio-economically diverse families. Lower parental education and family income were associated with higher rates of FH-ADHD and lower parental education with increased FH-autism. Thus, recruitment strategies have a meaningful impact on neurodiversity and the conclusions and generalisations that can be drawn. Specifically, recruitment using crowdsourcing websites could create a sample that is more representative of the wider population, compared to those recruited through university-related volunteer databases and social media.

Background. How often a child naps, during infancy, is believed to reflect both intrinsic factors, i.e. the need of an immature brain to consolidate information soon after it is acquired, and environmental factors. To date, the difficulty to account for important environmental factors that interfere with a child’s sleep needs (e.g., attending childcare) has clouded our ability to understand the role of intrinsic drivers of napping frequency. Methods. Here we investigate sleep patterns in association with two measures of cognitive ability, vocabulary size, measured with the Oxford-Communicative Development Inventory (N = 298) and cognitive executive functions, measured with the Early Executive Functions Questionnaire (N = 463), in a cohort of 8- to 38-month-olds. Importantly, because of the social distancing measures imposed during the Covid-19 Spring 2020 lockdown, in the UK, these children did not access daycare settings. Results. We find that children with more frequent but shorter naps than expected for their age had lower concurrent receptive vocabularies, lower cognitive executive functions and a slower increase in expressive vocabulary from spring to winter 2020, when age, sex and SES were accounted for. The negative association between vocabulary and frequency of naps was stronger in older children. Conclusions. These findings suggest that the structure of daytime sleep is an indicator of cognitive development and highlight the importance of considering environmental perturbations and age when investigating developmental correlates of sleep.

Previous studies have shown that caregivers’ sensitive, responsive interactions with young children can boost language development. We explored the association between caregivers’ sensitivity and the vocabulary development of their 8-to-36-month-olds during COVID-19 when family routines were unexpectedly disrupted. Measuring caregivers’ sensitivity from home interaction videos at three timepoints, we found that children who experienced more-sensitive concurrent interactions had higher receptive and expressive vocabularies (N=100). Children whose caregivers showed more-sensitive interactions at the beginning of the pandemic showed greater expressive vocabulary growth six (but not 12) months later (n=58). Significant associations with receptive vocabulary growth were not observed. Our findings highlight the importance of sensitivity at a time when other positive influences on language development were compromised.

Variation in infants’ home environment is implicated in their cognitive and psycho-social development. The pandemic has intensified variations in home environments through exacerbating socioeconomic inequalities, and increasing psychological stressors for some families. This study investigates the effects of parental (predominantly maternal) mental health, enriching activities and screen use on 280 24- to 52-month-olds’ executive functions, internalising and externalising problems, and pro-social behaviour; with socioeconomic status and social support as contextual factors. Our results indicate that aspects of the home environment are differentially associated with children’s cognitive and psycho-social development. Parents who experienced sustained mental distress during the pandemic tended to report higher child externalising and internalising problems, and executive function difficulties at follow-up. Children who spent more time engaged in enriching activities with their parents showed stronger executive functions and social competence six months later. Screen use levels during the first year of the pandemic were not associated with outcomes. To mitigate the risk of persistent negative effects for this ‘pandemic generation’ of infants, our study highlights the importance of supporting parents’ mental health. As our results demonstrate the impact of social support on mental health, investing in support services and interventions promoting building support networks are likely to be beneficial.

Older children with online schooling requirements, unsurprisingly, were reported to have increased screen time during the first COVID-19 lockdown in many countries. Here, we ask whether younger children with no similar online schooling requirements also had increased screen time during lockdown. We examined children’s screen time during the first COVID-19 lockdown in a large cohort (n = 2209) of 8-to-36-month-olds sampled from 15 labs across 12 countries. Caregivers reported that toddlers with no online schooling requirements were exposed to more screen time during lockdown than before lockdown. While this was exacerbated for countries with longer lockdowns, there was no evidence that the increase in screen time during lockdown was associated with socio-demographic variables, such as child age and socio-economic status (SES). However, screen time during lockdown was negatively associated with SES and positively associated with child age, caregiver screen time, and attitudes towards children’s screen time. The results highlight the impact of the COVID-19 lockdown on young children’s screen time.

The COVID-19 pandemic, and the resulting closure of daycare centers worldwide, led to unprecedented changes in children’s learning environments. This period of increased time at home with caregivers, with limited access to external sources (e.g., daycares) provides a unique opportunity to examine the associations between the caregiver-child activities and children’s language development. The vocabularies of 1742 children aged 8-36 months across 13 countries and 12 languages were evaluated at the beginning and end of the first lockdown period in their respective countries (from March to September 2020). Children who had less passive screen exposure and whose caregivers read more to them showed larger gains in vocabulary development during lockdown, after controlling for SES and other caregiver-child activities. Children also gained more words than expected (based on normative data) during lockdown; either caregivers were more aware of their child’s development, or vocabulary development benefited from intense caregiver-child interaction during lockdown or both. We discuss these results in the context of the extraordinary circumstances of the COVID-19 pandemic and highlight limitations of the study.

Early executive functions (EFs) lay the foundations for academic and social outcomes. In this parent-report study of 575 UK-based 8- to 36 month olds (218 followed longitudinally), we investigate how variation in the home environment before and during the 2020 pandemic relates to infants’ emerging EFs. Parent-infant enriching activities were positively associated with infant Cognitive Executive Function (CEF) (encompassing inhibitory control, working memory, cognitive flexibility). During the most-restrictive UK lockdown—but not subsequently—socioeconomic status (SES) was positively associated with levels of parent-infant enriching activities. Parents who regard fostering early learning, affection, and attachment as important were more likely to engage in parent-infant enriching activities, yet there was no significant pathway from parental attitudes or SES to CEF via activities. Infant screen use was negatively associated with CEF and Regulation. Screen use fully mediated the effect of SES on CEF, and partially mediated the effect of SES on regulation. Parental attitudes toward early learning, affection, and attachment did not significantly influence screen use. These results indicate that although parental attitudes influence the development of early EFs, interventions targeting attitudes as a means of increasing enriching activities, and thus EF are likely to be less effective than reducing barriers to engaging in enriching activities.

A surprising comprehension-production asymmetry in subject-verb (SV) agreement acquisition has been suggested in the literature, and recent research indicates that task-specific as well as language-specific features may contribute to this apparent asymmetry across languages. The present study investigates when during development children acquiring Mexican Spanish gain competence with 3rd-person SV agreement, testing production as well as comprehension in the same children aged between 3;6 and 5;7 years, and whether comprehension of SV agreement is modulated by the sentential position of the verb (i.e., medial vs. final position). Accuracy and sensitivity analyses show that comprehension performance correlates with SV agreement production abilities, and that comprehension of singular and plural third-person forms is not influenced by the sentential position of the agreement morpheme. Issues of the appropriate outcome measure and the role of structural familiarity in the development of abstract representations are discussed.

High-quality, centre-based education and care during the early years benefit cognitive development, especially in children from disadvantaged backgrounds. During the COVID-19 pandemic and its associated lockdowns, access to early childhood education and care (ECEC) was disrupted. We investigate how this period affected the developmental advantages typically offered by ECEC. Using parent-report data from 189 families living in the UK, we explore associations between time spent in ECEC by 8-to-36-month-olds, their socioeconomic background, and their growth in language and executive functions between Spring and Winter 2020. Receptive vocabulary growth was greater in children who continued to attend ECEC during the period, with a stronger positive effect for children from less advantaged backgrounds. The growth of cognitive executive functions (CEFs) was boosted by ECEC attendance during the period, regardless of socioeconomic background. Our findings highlight the importance of high-quality ECEC for the development of key skills and for levelling socioeconomic inequalities.

From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) compared with adult-directed speech (ADS). Yet IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multisite study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants’ IDS preference. As part of the multilab ManyBabies 1 project, we compared preference for North American English (NAE) IDS in lab-matched samples of 333 bilingual and 384 monolingual infants tested in 17 labs in seven countries. The tested infants were in two age groups: 6 to 9 months and 12 to 15 months. We found that bilingual and monolingual infants both preferred IDS to ADS, and the two groups did not differ in terms of the overall magnitude of this preference. However, among bilingual infants who were acquiring NAE as a native language, greater exposure to NAE was associated with a stronger IDS preference. These findings extend the previous finding from ManyBabies 1 that monolinguals learning NAE as a native language showed a stronger IDS preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes similar contributions to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments.

Determining the meanings of words requires language learners to attend to what other people say. However, it behooves a young language learner to simultaneously attend to what other people attend to, for example, by following the direction of their eye gaze. Sensitivity to cues such as eye gaze might be particularly important for bilingual infants, as they encounter less consistency between words and objects than monolinguals, and do not always have access to the same word learning heuristics (e.g., mutual exclusivity). In a pre-registered study, we tested the hypothesis that bilingual experience would lead to a more pronounced ability to follow another’s gaze. We used the gaze-following paradigm developed by Senju and Csibra (2008) to test a total of 93 6–9 month-old and 229 12–15 month-old monolingual and bilingual infants, in 11 labs located in 8 countries. Monolingual and bilingual infants showed similar gaze-following abilities,
and both groups showed age-related improvements in speed, accuracy, frequency and duration of fixations to congruent objects. Unexpectedly, bilinguals tended to make more frequent fixations to onscreen objects, whether or not they were cued by the actor. These results suggest that gaze sensitivity is a fundamental aspect of development that is robust to variation in language exposure.

There is evidence showing that both maturational and environmental factors can impact on later language development. On the one hand, preterm birth has been found to increase the risk of deficits in the preschool and school years. Preterm children show poorer auditory discrimination, reading difficulties, poor vocabulary, less complex expressive language and lower receptive understanding than their matched controls. On the other hand, socioeconomic status indicators (i.e. income, education, occupation) have been found to be strongly related to linguistic abilities during the preschool and school years. However, there is very little information about how these factors result in lower linguistic abilities. The present study addresses this issue. To do so, we investigated early phonological development in full and preterm infants from families classed as high or low SES. 76 infants were followed longitudinally at 7.5, 9, 10.5 and 12 months of age. At each test point, three studies explored infants’ phonetic, prosodic and phonotactic development, respectively. Results showed no significant differences between the phonetic or the phonotactic development of the preterm and the full-term infants. However, a time-lag between preterm and full-term developmental timing for prosody was found. Socioeconomic status did not have a significant effect on prosodic development. Nonetheless, phonetic and phonotactic development were affected by SES, infants from lower SES showed phonetic discrimination of non-native contrast and a preference for high-frequency sequences later than their more advantaged peers. Overall these results suggest that different constraints apply to the acquisition of different phonological subcomponents.

The field of psychology has become increasingly concerned with issues related to methodology and replicability. Infancy researchers face specific challenges related to replicability: high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations, amongst other factors. Addressing these concerns, we report on a large-scale, multi-site study aimed at 1) assessing the overall replicability of a single theoretically-important phenomenon and 2) examining methodological, situational, 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 were created using semi-naturalistic laboratory-based audio recordings in North American English. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three commonly-used infant discrimination methods (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s *d*) was 0.35 [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 infant-directed speech preference but suggest that its magnitude is modulated by development, native language experience, and testing procedure.

Vowel harmony is a linguistic phenomenon whereby vowels within a word share one or several of their phonological features, constituting a nonadjacent, and thus challenging, dependency to learn. It can be found in a large number of agglutinating languages, such as Hungarian and Turkish, and it may apply both at the lexical level (i.e., within word stems) and at the morphological level (i.e., between stems and their affixes). Thus, it might affect both lexical and morphological development in infants whose native language has vowel harmony. The current study asked at what age infants learning an irregular harmonic language, Hungarian, become sensitive to vowel harmony within word stems. In a head-turn preference study, 13-month-old, but not 10-month-old, Hungarian-learning infants preferred listening to nonharmonic VCV (vowel–consonant–vowel) pseudowords over vowel-harmonic ones. A control experiment with 13-month-olds exposed to French, a nonharmonic language, showed no listening preference for either of the sequences, suggesting that this finding cannot be explained by a universal preference for nonharmonic sequences but rather reflects language-specific knowledge emerging between 10 and 13 months of age. We discuss the implications of this finding for morphological and lexical learning.

The ability to compute non-adjacent regularities is key in the acquisition of a new language. In the domain of phonology/phonotactics, sensitivity to non-adjacent regularities between consonants has been found to appear between 7 and 10 months. The present study focuses on the emergence of a posterior-anterior (PA) bias, a regularity involving two non-adjacent vowels. Experiments 1 and 2 show that a preference for PA over AP (anterior-posterior) words emerges between 10 and 13 months in French-learning infants. Control experiments show that this bias cannot be explained by adjacent or positional preferences. The present study demonstrates that infants become sensitive to non-adjacent vocalic distributional regularities between 10 and 13 months, showing the existence of a delay for the acquisition of non-adjacent vocalic regularities compared to equivalent non-adjacent consonantal regularities. These results are consistent with the CV hypothesis, according to which consonants and vowels play different roles at different linguistic levels.

Previous studies have described the existence of a phonotactic bias called the Labial–Coronal

(LC) bias, corresponding to a tendency to produce more words beginning with a labial

consonant followed by a coronal consonant (i.e. ‘‘bat’’) than the opposite CL pattern (i.e.

‘‘tap’’). This bias has initially been interpreted in terms of articulatory constraints of the

human speech production system. However, more recently, it has been suggested that this

presumably language-general LC bias in production might be accompanied by LC and CL

biases in perception, acquired in infancy on the basis of the properties of the linguistic

input. The present study investigates the origins of these perceptual biases, testing infants

learning Japanese, a language that has been claimed to possess more CL than LC sequences,

and comparing them with infants learning French, a language showing a clear LC bias in its

lexicon. First, a corpus analysis of Japanese IDS and ADS revealed the existence of an overall

LC bias, except for plosive sequences in ADS, which show a CL bias across counts. Second,

speech preference experiments showed a perceptual preference for CL over LC plosive

sequences (all recorded by a Japanese speaker) in 13- but not in 7- and 10-month-old

Japanese-learning infants (Experiment 1), while revealing the emergence of an LC preference

between 7 and 10 months in French-learning infants, using the exact same stimuli.

These crosslinguistic behavioral differences, obtained with the same stimuli, thus reflect

differences in processing in two populations of infants, which can be linked to differences

in the properties of the lexicons of their respective native languages. These findings establish

that the emergence of a CL/LC bias is related to exposure to a linguistic input.

Recently, several studies have argued that infants capitalize on the statistical properties of natural languages to acquire the linguistic structure of their native language, but the kinds of constraints which apply to statistical computations remain largely unknown. Here we explored French-learning infants' perceptual preference for labial-coronal (LC) words over coronal-labial words (CL) words (e.g. preferring bat over tab) to determine whether this phonotactic preference is based on the acquisition of the statistical properties of the input based on a single phonological feature (i.e. place of articulation), multiple features (i.e. place and manner of articulation), or individual consonant pairs. Results from four experiments revealed that infants had a labial-coronal bias for nasal sequences (Experiment 1) and for all plosive sequences (Experiments 2 and 4) but a coronal-labial bias for all fricative sequences (Experiments 3 and 4), independently of the frequencies of individual consonant pairs. These results establish for the first time that constellations of multiple phonological features, defining broad consonant classes, constrain the early acquisition of phonotactic regularities of the native language.

Purpose In this study, the authors explored whether French-learning infants use nonadjacent phonotactic regularities in their native language, which they learn between the ages of 7 and 10 months, to segment words from fluent speech.

Method Two groups of 20 French-learning infants were tested using the head-turn preference procedure at 10 and 13 months of age. In Experiment 1, infants were familiarized with 2 passages: 1 containing a target word with a frequent nonadjacent phonotactic structure and the other containing a target word with an infrequent nonadjacent phonotactic structure in French. During the test phase, infants were presented with 4 word lists: 2 containing the target words presented during familiarization and 2 other control words with the same phonotactic structure. In Experiment 2, the authors retested infants' ability to segment words with the infrequent phonotactic structure.

Results Ten- and 13-month-olds were able to segment words with the frequent phonotactic structure, but it is only by 13 months, and only under the circumstances of Experiment 2, that infants could segment words with the infrequent phonotactic structure.

Conclusion These results provide new evidence showing that infant word segmentation is influenced by prior nonadjacent phonotactic knowledge.

Purpose: In the present study, we explore whether French-learning infants use non-adjacent

phonotactic regularities in their native language, which they learn between 7 and 10 months of

age, to segment words from fluent speech.

Method: Two groups of 20 French-learning infants were tested using the head-turn

preference procedure at 10 and 13 months of age. In Experiment 1, infants were familiarized

with two passages: one containing a target word with a frequent non-adjacent phonotactic

structure and the other passage containing a target word with an infrequent non-adjacent

phonotactic structure in French. During the test phase infants were presented with 4 word

lists: two containing the target words presented during familiarization and two other control

words with the same phonotactic structure. In Experiment 2, we retested infants’ ability to

segment words with the infrequent phonotactic structure.

Results: Ten- and 13-month-olds were able to segment words with the frequent phonotactic

structure, but it is only by 13 months, and only under the circumstances of Experiment 2, that

infants could segment words with the infrequent phonotactic structure.

Conclusions: Our results provide new evidence showing that infant word segmentation is

influenced by prior non-adjacent phonotactic knowledge.

The labial–coronal effect has originally been described as a bias to initiate a word with a labial consonant–vowel–coronal consonant (LC) sequence. This bias has been explained with constraints on the human speech production system, and its perceptual correlates have motivated the suggestion of a perception–production link. However, previous studies exclusively considered languages in which LC sequences are globally more frequent than their counterpart. The current study examined the LC bias in speakers of Japanese, a language that has been claimed to possess more CL than LC sequences. We first conducted an analysis of Japanese corpora that qualified this claim, and identified a subgroup of consonants (plosives) exhibiting a CL bias. Second, focusing on this subgroup of consonants, we found diverging results for production and perception such that Japanese speakers exhibited an articulatory LC bias, but a perceptual CL bias. The CL perceptual bias, however, was modulated by language of presentation, and was only present for stimuli recorded by a Japanese, but not a French, speaker. A further experiment with native speakers of French showed the opposite effect, with an LC bias for French stimuli only. Overall, we find support for a universal, articulatory motivated LC bias in production, supporting a motor explanation of the LC effect, while perceptual biases are influenced by distributional frequencies of the native language.

Languages instantiate many different kinds of dependencies, some holding between adjacent elements and others holding between nonadjacent elements. In the domain of phonology–phonotactics, sensitivity to adjacent dependencies has been found to appear between 6 and 10 months. However, no study has directly established the emergence of sensitivity to nonadjacent phonological dependencies in the native language. The present study focuses on the emergence of a perceptual Labial-Coronal (LC) bias, a dependency involving two nonadjacent consonants. First, Experiment 1 shows that a preference for monosyllabic consonant-vowel-consonant LC words over CL (Coronal- Labial) words emerges between 7 and 10 months in French-learning infants. Second, two experiments, presenting only the first or last two phonemes of the original stimuli, establish that the LC bias at 10 months cannot be explained by adjacent dependencies or by a preference for more frequent coronal consonants (Experiment 2a & b). At 7 months, by contrast, infants appear to react to the higher frequency of coronal consonants (Experiment 3a & b). The present study thus demonstrates that infants become sensitive to nonadjacent phonological dependencies between 7 and 10 months. It further establishes a

change between these two ages from sensitivity to local properties to nonadjacent dependencies in the phonological domain.

Previous work has shown that preterm infants are at higher risk for cognitive/language delays than full-term infants. Recent studies, focusing on prosody (i.e. rhythm, intonation), have suggested that prosodic perception development in preterms is indexed by maturational rather than postnatal/listening age. However, because prosody is heard in-utero, and preterms thus lose significant amounts of prenatal prosodic experience, both their maturation level and their prosodic experience (listening age) are shorter than that of full-terms for the same postnatal age. This confound does not apply to the acquisition of phonetics/phonotactics (i.e. identity and order of consonants/vowels), given that consonant differences in particular are only perceived after birth, which could lead to a different developmental pattern. Accordingly, we explore the possibility that consonant-based phonotactic perception develops according to listening age. Healthy French-learning full-term and preterm infants were tested on the perception of consonant sequences in a behavioral paradigm. The pattern of development for full-term infants revealed that 7-month-olds look equally at labial-coronal (i.e. /pat/) compared to coronal-labial sequences (i.e. /tap/), but that 10-month-olds prefer the labial-coronal sequences that are more frequent in the French lexicon. Preterm 10-month-olds (having 10 months of phonetic listening experience but 7 months of maturational age) behaved as full-term 10-month-olds. These results establish that preterm developmental timing for consonant-based phonotactic acquisition is based on listening age (experience with input). This questions the interpretation of previous results on prosodic acquisition in terms of maturational constraints, and raises the possibility that different constraints apply to the acquisition of different phonological subcomponents.