Julien Mayor

• PhD
• Professor (Full) at University of Oslo

Purpose This study introduces a framework to produce very short versions of the MacArthur–Bates Communicative Development Inventories (CDIs) by combining the Bayesian-inspired approach introduced by Mayor and Mani (2019) with an item response theory–based computerized adaptive testing that adapts to the ability of each child, in line with Makransky...

The present study explores the viability of using tablets in assessing early word comprehension by means of a two-alternative forced-choice task. Forty-nine 18-20-month-old Norwegian toddlers performed a touch-based word recognition task, in which they were prompted to identify the labelled target out of two displayed items on a touchscreen tablet....

In recent years, the popularity of tablets has skyrocketed and there has been an explosive growth in apps designed for children. Howhever, many of these apps are released without tests for their effectiveness. This is worrying given that the factors influencing children’s learning from touchscreen devices need to be examined in detail. In particula...

Previous research suggests that exposure to accent variability can affect toddlers’ familiar word recognition and word comprehension. The current preregistered study addressed the gap in knowledge on early language development in infants exposed to two dialects from birth and assessed the role of dialect similarity in infants’ word recognition and...

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 activit...

Growing up with multiple siblings might negatively affect a child’s language development. This study examined the associations between birth order, sibling characteristics and parent-reported vocabulary size in 6,163 Norwegian 8–36-month-old children (51.4% female). Results confirmed that birth order was negatively associated with vocabulary, yet e...

Non-nutritive sucking (NNS), including pacifier use and thumb sucking, is common in infants and has been associated with both positive and negative developmental outcomes. While NNS is known to reduce distress, sustained use has been linked to lower vocabulary scores (Muñoz et al., 2024). The present longitudinal study investigates the relationship...

Caregivers often modulate their speech when interacting with infants, adapting a register that has been suggested to have attentional, affective and didactic purposes. The present preregistered study examined the longitudinal trajectories of a diverse range of acoustic features of infant-directed speech (IDS) and compared these with adult-directed...

From early on, infants show a preference for infant-directed speech (IDS) over adult-directed speech (ADS), and exposure to IDS has been correlated with language outcome measures such as vocabulary. The present multi-laboratory study explores this issue by investigating whether there is a link between early preference for IDS and later vocabulary s...

Growing up with multiple siblings might negatively affect a child’s language development. This study examined the associations between birth order, sibling characteristics and parent-reported vocabulary size in 6,163 Norwegian 8–36-month-old children (51.4% female). Results confirmed that birth order was negatively associated with vocabulary, yet e...

Growing up with multiple siblings might negatively affect a child’s language development. This study examined the associations between birth order, sibling characteristics and parent-reported vocabulary size in 6,163 Norwegian 8–36-month-old children (51.4% female). Results confirmed that birth order was negatively associated with vocabulary, yet e...

In the current pre-registered study, we examined the associations between shared book reading, daily screen time, and vocabulary size in 1,442 12- and 24-month-old Norwegian infants. Our results demonstrate a positive association between shared reading and vocabulary in both age groups, and a negative association between screen time and vocabulary...

The acoustic properties of infant-directed speech (IDS) and the functions that IDS may serve in language development have drawn noticeable interest in infant development research. However, previous research has mostly explored IDS in mothers and the preference for maternal IDS, with few studies assessing the role of exposure to or parenthood experi...

Test‐retest reliability—establishing that measurements remain consistent across multiple testing sessions—is critical to measuring, understanding, and predicting individual differences in infant language development. However, previous attempts to establish measurement reliability in infant speech perception tasks are limited, and reliability of fre...

In the current preregistered study, we tested n=67 6-month-old Norwegian infants’ discrimination of a native vowel contrast /y-i/ and a non-native (British) vowel contrast /ʌ-æ/ in an eye-tracking habituation paradigm. Our results showed that, on a group level, infants did not discriminate either contrast. Yet, exploratory analyses revealed a negat...

Caregivers often modulate their speech when interacting with infants, adapting a register that has been suggested to have attentional, affective, and didactic purposes. The present preregistered study examined the longitudinal trajectories of a diverse range of acoustic features of infant-directed speech (IDS), and compared these to adult-directed...

Color terms divide the color spectrum differently across languages. Previous studies have reported that speakers of languages that have different words for light and dark blue (e.g., Russian siniy and goluboy ) discriminate color chips sampled from these two linguistic categories faster than speakers of languages that use one basic color term for b...

There is substantial evidence that infants prefer infant-directed speech (IDS) to adult-directed speech (ADS). The strongest evidence for this claim has come from two large-scale investigations: i) a community-augmented meta-analysis of published behavioral studies and ii) a large-scale multi-lab replication study. In this paper, we aim to improve...

This study assessed the relationship between preschoolers’ directly and indirectly assessed emotion word comprehension. Forty-nine two-to-five-year-old Norwegian children were assessed in a tablet-based 4-alternative forced choice (AFC) task on their comprehension of six basic and six complex emotions using facial expression photographs. Parents re...

Color terms divide the color spectrum differently across languages. Previous studies reported that speakers of languages that have different words for light and dark blue (e.g., Russian "siniy" and "goluboy") discriminate color chips sampled from these two linguistic categories faster than speakers of languages that use one basic color term for blu...

Pacifier use during childhood has been hypothesized to interfere with language processing, but, to date, there is limited evidence revealing detrimental effects of prolonged pacifier use on infant vocabulary learning. In the present study, parents of 12‐ and 24‐month‐old infants were recruited in Oslo (Norway). The sample included 1187 monolingual...

Previous research suggests that acoustic features of infant-directed speech (IDS) might be beneficial for infants’ language development. However, consonants have gained less attention than vowels and prosody. In the current study, we examined voice onset time (VOT) – a distinguishing cue for stop consonant contrasts – in IDS and adult-directed spee...

The Early Parenting Attitudes Questionnaire (EPAQ; Hembacher & Frank, 2020) was developed in the U.S. to assess parents’ beliefs, knowledge, ideas, and attitudes about parenting. Given the diversity of parenting practices among cultures, it is essential to establish the cross-cultural validity of the instruments used to measure them. For this reaso...

Measuring eye movements remotely via the participant's webcam promises to be an attractive methodological addition to in‐person eye‐tracking in the lab. However, there is a lack of systematic research comparing remote web‐based eye‐tracking with in‐lab eye‐tracking in young children. We report a multi‐lab study that compared these two measures in a...

Previous research on infant-directed speech (IDS) and its role in infants’ language development has largely focused on mothers, with fathers being investigated scarcely. Here we examine the acoustics of IDS as compared to adult-directed speech (ADS) in Norwegian mothers and fathers to 8-month-old infants, and whether these relate to direct (eye-tra...

There is substantial evidence that infants prefer infant-directed speech (IDS) to adult-directed speech (ADS). The strongest evidence for this claim has come from two large-scale investigations: i) a community-augmented meta-analysis of published behavioral studies and ii) a large-scale multi-lab replication study. In this paper, we aim to improve...

Test-retest reliability — establishing that measurements remain consistent across multiple testing sessions — is critical to measuring, understanding, and predicting individual differences in infant language development. However, previous attempts to establish measurement reliability in infant speech perception tasks are limited, and reliability of...

The COVID-19 pandemic massively changed the context and feasibility of developmental research. This new reality, as well as considerations about sample diversity and naturalistic settings for developmental research, highlights the need for solutions for online studies. In this article, we present e-Babylab, an open-source browser-based tool for unm...

In the current pre-registered study, we examined the associations between shared book reading, daily screen time, and vocabulary size in 1,442 12- and 24-month-old Norwegian infants. Our results demonstrate a positive association between shared reading and vocabulary in both age groups, and a negative association between screen time and vocabulary...

Measuring eye movements remotely via the participant’s webcam promises to be an attractive methodological addition to in-person eye-tracking in the lab. However, there is a lack of systematic research comparing remote web-based eye-tracking with in-lab eye-tracking in young children. We report a multi-lab study that compared these two measures in a...

Much of our basic understanding of cognitive and social processes in infancy relies on measures of looking time, and specifically on infants’ visual preference for a novel or familiar stimulus. However, despite being the foundation of many behavioral tasks in infant research, the determinants of infants’ visual preferences are poorly understood, an...

Previous research on infant-directed speech (IDS) and its role in infants’ language development has largely focused on mothers, with fathers being investigated scarcely, if at all. Here we examine the acoustics of IDS as compared to adult-directed speech (ADS) in Norwegian mothers and fathers to 8–month-old infants, and whether these relate to dire...

This study assessed the relationship between indirect (parent-reported) and direct (4-alternative-foced choice, AFC) measures of emotion word vocabulary in 49 two-to-five-year-old Norwegian children. Six basic emotions and six complex emotions were assessed. Neither parent-reported emotion word comprehension nor production predicted children’s AFC-...

Previous research suggests that exposure to accent variability can affect toddlers’ familiar word recognition and word comprehension. The current preregistered study addressed the gap in knowledge on early language development in infants exposed to two dialects from birth and assessed the role of dialect similarity in infants’ word recognition and...

Yarkoni's analysis clearly articulates a number of concerns limiting the generalizability and explanatory power of psychological findings, many of which are compounded in infancy research. ManyBabies addresses these concerns via a radically collaborative, large-scale and open approach to research that is grounded in theory-building, committed to di...

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 C...

The present study examines the acoustic properties of infant-directed speech (IDS) as compared to adult-directed speech (ADS) in Norwegian parents of 18-month-old toddlers, and whether these properties relate to toddlers’ expressive vocabulary size. Twenty-one parent- toddler dyads from Tromsø, Northern Norway participated in the study. Parents (16...

Children learn words in ambiguous situations, where multiple objects can potentially be referents for a new word. Yet, researchers debate whether children maintain a single word-object hypothesis – and revise it if falsified by later information – or whether children establish a network of word-object associations whose relative strengths are modul...

Pacifier use during childhood has been hypothesised to interfere with language processing.Recent evidence suggests that transient use of an object in the infant’s mouth (a teething toy)impairs speech sound discrimination and that extensive pacifier use translates into slowerprocessing of abstract words at 7-8 years, but to date no studies have reve...

Multi-accent environments offer rich but inconsistent language input, as words are produced differently across accents. The current study examined, in two experiments, whether multi-accent variability affects infants’ ability to learn words and whether toddlers’ prior experience with accents modulates learning. In Experiment 1, two-and-a-half-year-...

The ability to learn and apply rules lies at the heart of cognition. In a seminal study, Marcus, Vijayan, Rao, and Vishton (1999) reported that seven-month-old infants learned abstract rules over syllable sequences and were able to generalize those rules to novel syllable sequences. Dozens of studies have since extended on that research using diffe...

This study 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 11 countries. Caregivers reported that young infants and toddlers with no online schooling requirements were exposed to more screen time during lockdown than before lockdown. While this was exace...

Yarkoni’s analysis clearly articulates a number of concerns limiting the generalizability and explanatory power of psychological findings, many of which are compounded in infancy research. ManyBabies addresses these concerns via a radically collaborative, large-scale and open approach to research that is grounded in theory-building, committed to di...

Early vocabularies typically contain more nouns than verbs. Yet, the strength of this noun-bias varies across languages and cultures. Two main theories have aimed at explaining such variations; either that the relative importance of nouns vs. verbs is specific to the language itself, or that extra-linguistic factors shape early vocabulary structure...

The present study explores the viability of using tablets in assessing early word comprehension by means of a two‐alternative forced‐choice task. Forty‐nine 18–20‐month‐old Norwegian toddlers performed a touch‐based word recognition task, in which they were prompted to identify the labeled target out of two displayed items on a touchscreen tablet....

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 activit...

The COVID-19 pandemic massively changed the context and feasibility of developmental research. This new reality as well as considerations, e.g., about sample diversity and naturalistic settings for developmental research, indicate the need for solutions for online studies. In this article, we present e-Babylab, an open-source browser-based tool for...

Recency effects are well documented in the adult and infant literature: recognition and recall memory are better for recently occurring events. We explore recency effects in infant categorization, which does not merely involve memory for individual items, but the formation of abstract category representations. We present a computational model of in...

Children employ multiple cues to identify the referent of a novel word. Novel words are often embedded in sentences and children have been shown to use syntactic cues to differentiate between types of words (adjective vs. nouns) and between types of nouns (count vs. mass nouns). In this study, we show that children learning Malay (N = 67), a numera...

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...

Several studies have shown that unbalanced bilinguals activate both of their languages simultaneously during L2 processing; however, evidence for L2 activation while participants are tested exclusively in their L1 has been more tenuous. Here, we investigate whether bilingual participants implicitly activate the label for a picture in their two lang...

The past 5 years have witnessed claims that infants as young as six months of age understand the meaning of several words. To reach this conclusion, researchers presented infants with pairs of pictures from distinct semantic domains and observed longer looks at an object upon hearing its name as compared with the name of the other object. However,...

Children learn words in ambiguous situations, where multiple objects can potentially be referents for a new word. Yet, researchers debate whether children form and maintain a single word-object hypothesis – and revise it if falsified by later information – or whether children establish a network of word-object associations whose relative strengths...

The MacArthur–Bates Communicative Development Inventories (CDIs) are among the most widely used evaluation tools for early language development. CDIs are filled in by the parents or caregivers of young children by indicating which of a prespecified list of words and/or sentences their child understands and/or produces. Despite the success of these...

To communicate successfully, speakers need to use words that are understood by their listeners; they thus need to understand that others have vocabularies different than their own. A key question is whether this social cognition skill is already present in infancy, and whether it can have an impact on early language production. Analysis of the voca...

Despite its recognized importance for cultural transmission, little is known about the role imitation plays in language learning. Three experiments examine how rates of imitation vary as a function of qualitative differences in the way language is used in a small indigenous community in Oaxaca, Mexico and three Western comparison groups. Data from...

In Polynesian phonology and morphology, passives have traditionally been analyzed in two steps: (1) by assigning a single default pattern, which has been characterized as fully predictable and productive; and (2) by lexicalizing the remaining patterns, which have been assumed to be unpredictable. We overturn this assumption of unpredictability here...

The TRACE model of speech perception (McClelland & Elman, 1986) is used to simulate results from the infant word recognition literature, to provide a unified, theoretical framework for interpreting these findings. In a first set of simulations, we demonstrate how TRACE can reconcile apparently conflicting findings suggest-ing, on the one hand, that...

To what extent do toddlers have shared vocabularies? We examined CDI data collected from 14607 infants and toddlers in five countries and measured the amount of variability between individual lexicons during development for both comprehension and production. Early lexicons are highly overlapping. However, beyond 100 words, toddlers share more words...

For the last 20 years, developmental psychologists have measured the variability in lexical development of infants and toddlers using the MacArthur-Bates Communicative Development Inventories (CDIs) - the most widely used parental report forms for assessing language and communication skills in infants and toddlers. We show that CDI reports can serv...

Despite a “Cambrian” explosion in the number of citation metrics used (Van Noorden, 2010), the impact factor (IF) of a journal remains a decisive factor of choice when publishing your ultimate research results and evaluating research productivity. Most other citation metrics correlate with the IF and there is little doubt that they reflect the over...

Recent reports on perception and production of speech segments in simultaneous bilinguals, who acquired both of their languages at the same time-frame (from birth), suggest that they do not always exhibit abilities similar to those of the native monolinguals of the same languages [i.e., Guion (2003); Molnar et al. (2009); Sundara and Polka (2008)]...

We present a neurocomputational model with self-organizing maps that accounts for the emergence of taxonomic responding and fast mapping in early word learning, as well as a rapid increase in the rate of acquisition of words observed in late infancy. The quality and efficiency of generalization of word-object associations is directly related to the...

A substantial body of experimental evidence has demonstrated that labels have an impact on infant categorization processes. Yet little is known regarding the nature of the mechanisms by which this effect is achieved. We distinguish between two competing accounts: supervised name-based categorization and unsupervised feature-based categorization. We...

For the last twenty years, many researchers interested in language acquisition have quantified the receptive and productive vocabulary of infants using CDIs – checklists of words filled in by the caregiver. While it is generally accepted that the caregiver can reliably say whether the infant knows and/or produces a given word, we lack an estimate f...

Very young infants possess a capacity to discriminate contrasts that are not present in their native language. Later in develop-ment, they lose this capacity while improving the discrimina-tion of sounds in their native language and progressively tun-ing their speech sensitivity to increase the phonological speci-ficity of their lexical represenati...

For the last twenty years, many researchers interested in lan-guage acquisition have quantified the receptive and productive vocabulary of infants using CDIs – checklists of words filled in by the caregiver. While it is generally accepted that the care-giver can reliably say whether the infant knows and/or pro-duces a given word, we lack an estimat...

http://www.ling-phil.ox.ac.uk/files/uploads/OWP2009.pdf

We propose a computational model of the impact of labels on visual categorisation. The proposed model is based on self-organising maps. The model successfully reproduces the ex-periments demonstrating the impact of labelling on infant cat-egorisation reported in Plunkett, Hu, and Cohen (2008). Two architectures are explored. Both mimic infant behav...

We investigate from a modelling perspective how lexical structure can be grounded in the underlying speech and visual categories that infants have al-ready acquired. We demonstrate that the formation of well-structured categories is an important prerequisite for successful generalisation of cross-modal associations such that even after a single pre...

In randomly connected networks of pulse-coupled elements a time-dependent input signal can be buffered over a short time. We studied the signal buffering properties in simulated networks as a function of the networks' state, characterized by both the Lyapunov exponent of the microscopic dynamics and the macroscopic activity derived from mean-field...

Varied sensory systems use noise in order to enhance detection of weak signals. It has been conjectured in the literature that this effect, known as stochastic resonance, may take place in central cognitive processes such as memory retrieval of arithmetical multiplication. We show, in a simplified model of cortical tissue, that complex arithmetical...

Thèse no 3278 sc. EPF Lausanne. Literaturverz. EPFL, Lausanne

We investigate the performance of sparsely-connected networks of integrate-and-fire neurons for ultra-short term information processing. We exploit the fact that the population activity of networks with balanced excitation and inhibition can switch from an oscillatory firing regime to a state of asynchronous irregular firing or quiescence depending...

The storage and short-term memory capacities of recurrent neural networks of spiking neurons are investigated. We demonstrate that it is possible to process online many superimposed streams of input. This is despite the fact that the stored information is spread throughout the network. We show that simple output structures are powerful enough to ex...

We present a model of early lexical acquisition. Successful word learning builds on pre-existing, self-organising categori-sation capacities and through joint attentional events between the infant and the caregiver. Our model successfully accounts for the emergence of a lexical constraint, taxonomic respond-ing, as well as a steep increase in the r...

Infants do not learn words at a constant rate. During the second year of life, a dramatic increase in the speed of word learning is observed. Different mechanisms explaining this vocabulary spurt have been proposed, either through endogenous factors such as learning capacity or exogenous factors, such as frequency of word usage. We demonstrate that...

THESE 3278 (2005) Mayor, Julien ; ABSTRACT ENG Abstract Sensory memory is the first step of a complex memorization process. Sensory information is buffered in a "sensory store" for a short period. Then part of it is transferred to working memory, where information can be actively processed and, eventually, through its rehearsal, can be memorized an...