Infant Recognition of Hebrew Vocalic Word Patterns

The ability of infants to recognize phonotactic patterns in their native language is widely acknowledged. However, the specific ability of infants to recognize patterns created by nonadjacent vowels in words has seldom been investigated. In Semitic languages such as Hebrew, groups of multisyllabic words are identical in their nonadjacent vowel sequences and stress position but differ in the consonants interposed between the vowels. The goals of this study were to assess whether infants learning Hebrew show a preference for (1) a nonadjacent vocalic pattern or template, common in Hebrew nouns (CéCeC), over a nonattested nonadjacent vocalic pattern (CóCoC), and (2) a nonadjacent vocalic pattern common in Hebrew words (CaCóC) over an existing but less common pattern (CaCéC). Twenty Hebrew‐learning infants aged 8 to 11 months were presented with lists of nonsense words featuring the first two patterns (Experiment 1), and 20 were presented with nonsense words featuring the second two patterns (Experiment 2). The results showed longer listening to CéCeC than to CóCoC lists and to CaCóC than to CaCéC lists, suggesting that infants recognized the common nonadjacent vocalic patterns in both cases. The study thus demonstrates that Hebrew‐learning infants are able to disregard the intervening consonants within words and generalize their vocalic pattern to previously unheard nonwords, whether this pattern includes identical or different vowels and regardless of the rhythmic pattern of the word (trochaic or iambic). Analysis of the occurrence of the relevant vowel patterns in input speech in three Hebrew corpora (two addressed to children and one to adults) suggests that exposure to these patterns in words underlies the infants' preferences.     

The Developmental Trajectory of Nonadjacent Dependency Learning

We investigated the developmental trajectory of nonadjacent dependency learning in an artificial language. Infants were exposed to 1 of 2 artificial languages with utterances of the form [aXc or bXd] (Grammar 1) or [aXd or bXc] (Grammar 2). In both languages, the grammaticality of an utterance depended on the relation between the 1 st and 3rd elements, whereas the intervening element varied freely. High variability of the middle element is known to contribute to perception of nonadjacent dependencies (Góomez, 2002), but the developmental trajectory of such learning is unknown. Experiment 1 replicated the study of Gómez with a younger age group and a more subtle variability manipulation. Twelve‐month‐olds failed to track nonadjacent dependencies under conditions tested here (Experiments 2a and 2b), but by 15 months, infants are beginning to track this structure (Experiment 3). Such learning has implications for understanding how infants might begin to acquire similar structure in natural language.     

Emergence of a consonant bias during the first year of life: New evidence from own‐name recognition

Recent evidence suggests that during the first year of life, a preference for consonant information during lexical processing (consonant bias) emerges, at least for some languages like French. Our study investigated the factors involved in this emergence as well as the developmental consequences for variation in consonant bias emergence. In a series of experiments, we measured 5‐, 8‐, and 11‐month‐old French‐learning infants orientation times to a consonant or vowel mispronunciation of their own name, which is one of the few word forms familiar to infants at this young age. Both 5‐ and 8‐month‐olds oriented longer to vowel mispronunciations, but 11‐month‐olds showed a different pattern, initially orienting longer to consonant mispronunciations. We interpret these results as further evidence of an initial vowel bias, with consonant bias emergence by 11 months. Neither acoustic‐phonetic nor lexical factors predicted preferences in 8‐ and 11‐month‐olds. Finally, counter to our predictions, a vowel bias at the time of test for 11‐month‐olds was related to later productive vocabulary outcomes.     

Preverbal Infants' Ability to Encode the Outcome of Distributive Actions

This research examined whether 10‐month‐old infants expect agents to perform equal distribution of resources. In Experiment 1, infants saw a distributor performing either an equal distribution where one strawberry was given to each of two recipients, or an unequal distribution that favored one of the recipients. Infants looked longer at the unequal test event, suggesting that they expected the strawberries to be distributed equally. In Experiment 2, the potential recipients were replaced with inanimate objects to rule out a lower‐level alternative explanation of the results in Experiment 1 based on symmetric movement of the distributor. Infants' looking times did not reveal a preference for one of the two outcomes of the test events (i.e., symmetric or asymmetric movement). Experiment 3 controlled for the role of the distributive action, that is, here the distributors only removed barriers revealing strawberries that the recipients already had. No preference was observed when an equal or unequal initial allocation of resources was revealed. Experiment 4 assessed whether infants relied on affiliative information provided by the distributor's movements. The distributor made the same movements as in Experiment 1, but without distributing any strawberries, and no difference in looking times was observed. These findings support the view that preverbal infants expect agents to behave according to a simple principle: Resources are to be distributed equally among equivalent recipients. We discuss the possible links between such reactions and the emergence of an early sense of fairness.     

Stress Pattern Preference in Spanish‐Learning Infants: The Role of Syllable Weight

As a result of exposure, infants acquire biases that conform to the rhythmic properties of their native language. Previous lexical stress preference studies have shown that English‐ and German‐, but not French‐learning infants, show a bias toward trochaic words. The present study explores Spanish‐learning infants' lexical stress preferential patterns and the role of syllable weight at 9 months of age. Spanish is a syllable‐timed language with no vowel reduction and variable stress. Around 50% of the word types in Spanish are disyllabic, with a superior proportion of trochees than iambs (60% and 40%, respectively). Experiment 1 with CV.CV pseudo‐words failed to reveal a clear trochaic bias in 9‐month‐old Spanish‐learning infants. However, when preference was explored with items containing a heavy syllable (CVC.CV and CV.CVC, respectively), both a trochaic (Experiment 2) and an iambic preference (Experiment 3) could be elicited. These results suggest that knowledge about the close and highly regular link between heavy syllables and stress assignment in Spanish can be easily acquired and determines infants' preference at 9 months of age, while for CV.CV items, the trochaic bias appears to be weak. Our results broaden the current knowledge on the factors that determine the emergence of rhythmic biases.     

Twelve‐Month‐Olds Know Their Cups From Their Keps and Tups

Fourteen‐month‐olds are sensitive to mispronunciations of the vowels and consonants in familiar words (N. Mani & K. Plunkett (2007), Journal of Memory and Language, 57, 252; D. Swingley & R. N. Aslin (2002), Psychological Science, 13, 480). To examine the development of this sensitivity further, the current study tests 12‐month‐olds’ sensitivity to different kinds of vowel and consonant mispronunciations of familiar words. The results reveal that vocalic changes influence word recognition, irrespective of the kinds of vocalic changes made. While consonant changes influenced word recognition in a similar manner, this was restricted to place and manner of articulation changes. Infants did not display sensitivity to voicing changes. Infants’ sensitivity to vowel mispronunciations, but not consonant mispronunciations, was influenced by their vocabulary size—infants with larger vocabularies were more sensitive to vowel mispronunciations than infants with smaller vocabularies. The results are discussed in terms of different models attempting to chart the development of acoustically or phonologically specified representations of words during infancy.     

Factors affecting infant toy preferences: Age,gender, experience,motor development,and parental attitude

In contrast to the anecdotal claim that “male infants like cars and female infants like dolls,” previous studies have reported mixed findings for gender‐related toy preferences in infancy. In Experiment 1, we explored the emergence of gender‐related preferences using face–car pairs (Experiment 1a, n = 51, 6–20 months) or face–stove pairs (Experiment 1b, n = 54, 6–20 months). In Experiment 2 (n = 42, 14–16 months), we explore the effect of toy properties, infants' past toy exposure, activity levels, and parental attitudes on such preferences using a wider range of toys. For both studies, infants demonstrated a general preference for faced stimuli over other objects, except for male infants who showed no preference between dolls and cars at around 15 months. Infants' prior experience participating in motor‐intensive activities, with wheeled toys and parental attitudes appeared to relate to female infants' preferences for dynamic toys. These results indicate a range of factors influence gendered toy preferences and suggest that nurture plays an important role.     

Sensitivity to Word‐Final Phonotactics in 9‐ to 16‐Month‐Old Infants

Previous research has shown that infants begin to display sensitivities to language‐specific phonotactics and probabilistic phonotactics at around 9 months of age. However, certain phonotactic patterns have not yet been examined, such as contrast neutralization, in which phonemic contrasts are neutralized typically in syllable‐ or word‐final position. Thus, the acquisition of contrast neutralization is dependent on infants' ability to perceive certain contrasts in final position. The studies reported here test infants' sensitivity to voicing neutralization in word‐final position and infants' discrimination of voicing and place of articulation (POA) contrasts in word‐initial and word‐final position. Nine and 11‐month‐old Dutch‐learning infants showed no preference for legal versus illegal voicing phonotactics that were contrasted in word‐final position. Furthermore, 10‐month‐old infants showed no discrimination of voicing or POA contrasts in word‐final position, whereas they did show sensitivity to the same contrasts in word‐initial position. By 16 months, infants were able to discriminate POA contrasts in word‐final position, although showing no discrimination of the word‐final voicing contrast. These findings have broad implications for models of how learners acquire the phonological structures of their language, for the types of phonotactic structures to which infants are presumed to be sensitive, and for the relative sensitivity to phonemic distinctions by syllable and word position during acquisition.     

Bias for Vocalic Over Consonantal Information in 6‐Month‐Olds

Human languages rely on the ability to learn and produce an indefinite number of words by combining consonants and vowels in a lawful manner. The categorization of speech representations into consonants and vowels is evidenced by the tendency of adult speakers, attested in many languages, to use consonants and vowels for different tasks. Consonants are favored in lexical tasks, while vowels are favored to learn structural regularities. Recent results suggest that this specialization is already observable at 12 months of age in Italian participants. Here, we investigated the representations of younger infants. In a series of anticipatory looking experiments, we showed that Italian 6‐month‐olds rely more on vowels than on consonants when learning the predictions made by individual words (Experiment 1) and are better at generalizing a structure when it is implemented over vowels than when it is implemented over consonants (Experiments 2 and 3). Until 6 months of age, infants thus show a general vocalic bias, which contrasts with the specialization previously observed at 12 months. These results suggest the format of speech representations changes during the second semester of life.     

The Emergence and Stability of the Attentional Bias to Fearful Faces in Infancy

Several studies have shown that at 7 months of age, infants display an attentional bias toward fearful facial expressions. In this study, we analyzed visual attention and heart rate data from a cross‐sectional study with 5‐, 7‐, 9‐, and 11‐month‐old infants (Experiment 1) and visual attention from a longitudinal study with 5‐ and 7‐month‐old infants (Experiment 2) to examine the emergence and stability of the attentional bias to fearful facial expressions. In both experiments, the attentional bias to fearful faces appeared to emerge between 5 and 7 months of age: 5‐month‐olds did not show a difference in disengaging attention from fearful and nonfearful faces, whereas 7‐ and 9‐month‐old infants had a lower probability of disengaging attention from fearful than nonfearful faces. Across the age groups, heart rate (HR) data (Experiment 1) showed a more pronounced and longer‐lasting HR deceleration to fearful than nonfearful expressions. The results are discussed in relation to the development of the perception and experience of fear and the interaction between emotional and attentional processes.     

Picture Perception in Infants: Generalization From Two‐Dimensional to Three‐Dimensional Displays

Two experiments investigated 9‐month‐old infants’ abilities to recognize the correspondence between an actual three‐dimensional (3D) object and its two‐dimensional (2D) representation, looking specifically at representations that did not literally depict the actual object: schematic line drawings. In Experiment 1 , infants habituated to a line drawing of either a doll or a sheep and were then tested with the actual objects themselves. Infants habituated to the sheep drawing recovered to the unfamiliar but not the familiar object, showing a novelty preference. Infants habituated to the doll drawing, however, recovered to both familiar and unfamiliar objects, failing to show any preference between the two. In Experiment 2 , infants habituated to the 3D objects and were then tested with the 2D line drawings. In this case, both groups of infants showed a preference only for the novel displays. Together these findings demonstrate that 9‐month‐old infants recognize the correspondence between 3D objects and their 2D representations, even when these representations are not literal copies of the objects themselves.     

Infants' First Words are not Phonetically Specified: Own Name Recognition in British English‐Learning 5‐Month‐Olds

By the end of their first year of life, infants’ representations of familiar words contain phonetic detail; yet little is known about the nature of these representations at the very beginning of word learning. Bouchon et al. ( 2015 ) showed that French‐learning 5‐month‐olds could detect a vowel change in their own name and not a consonant change, but also that infants reacted to the acoustic distance between vowels. Here, we tested British English‐learning 5‐month‐olds in a similar study to examine whether the acoustic/phonological characteristics of the native language shape the nature of the acoustic/phonetic cues that infants pay attention to. In the first experiment, British English‐learning infants failed to recognize their own name compared to a mispronunciation of initial consonant (e.g., Molly versus Nolly) or vowel (e.g., April versus Ipril). Yet in the second experiment, they did so when the contrasted name was phonetically dissimilar (e.g., Sophie versus Amber). Differences in phoneme category (stops versus continuants) between the correct consonant versus the incorrect one significantly predicted infants’ own name recognition in the first experiment. Altogether, these data suggest that infants might enter into a phonetic mode of processing through different paths depending on the acoustic characteristics of their native language.     

Robust effects of stress on early lexical representation

This study aims to elucidate the factors that affect the robustness of word form representations by exploring the relative influence of lexical stress and segmental identity (consonant vs. vowel) on infant word recognition. Our main question was which changes to the words may go unnoticed and which may lead the words to be unrecognizable. One‐hundred 11‐month‐old Hebrew‐learning infants were tested in two experiments using the Central Fixation Procedure. In Experiment 1, 20 infants were presented with iambic Familiar and Unfamiliar words. The infants listened longer to Familiar than to Unfamiliar words, indicating their recognition of frequently heard word forms. In Experiment 2, four groups of 20 infants each were tested in each of four conditions involving altered iambic Familiar words contrasted with iambic Unfamiliar nonwords. In each condition, one segment in the Familiar word was changed—either a consonant or a vowel, in either the first (unstressed) or the second (stressed) syllable. In each condition, recognition of the Familiar words despite the change indicates a less accurate or less well‐specified representation. Infants recognized Familiar words despite changes to the weak (first) syllable, regardless of whether the change involved a consonant or a vowel (conditions 2a, 2c). However, a change of either consonant or vowel in the stressed (second) syllable blocked word recognition (conditions 2b, 2d). These findings support the proposal that stress pattern plays a key role in early word representation, regardless of segmental identity.     

Maternal Responsiveness and the Development of Directed Vocalizing in Social Interactions

For effective communication, infants must develop the phonology of sounds and the ability to use vocalizations in social interactions. Few studies have examined the development of the pragmatic use of prelinguistic vocalizations, possibly because gestures are considered hallmarks of early pragmatic skill. The current study investigated infant vocal production and maternal responsiveness to examine the relationship between infant and maternal behavior in the development of infants' vocal communication. Specifically, we asked whether maternal responses to vocalizations could influence the development of prelinguistic vocal usage, as has been documented in recent experimental studies exploring the relation between maternal responses and phonological development. Twelve mother–infant dyads participated over a six‐month period (between 8 and 14 months of age). Mothers completed the MacArthur Communicative Development Inventory when infants were 15 months old. Maternal sensitive responses to infant vocalizations in the previous months predicted infants' mother‐directed vocalizations in the following months, rather than overall response rate. Furthermore, mothers' sensitive responding to mother‐directed vocalizations was correlated with an increase in developmentally advanced, consonant–vowel vocalizations and some language measures. This is the first study to document a social shaping mechanism influencing developmental change in pragmatic usage of vocalizations in addition to identifying the specific behaviors underlying development.     

Better Processing of Consonantal Over Vocalic Information in Word Learning at 16 Months of Age

Previous research using the name‐based categorization task has shown that 20‐month‐old infants can simultaneously learn 2 words that only differ by 1 consonantal feature but fail to do so when the words only differ by 1 vocalic feature. This asymmetry was taken as evidence for the proposal that consonants are more important than vowels at the lexical level. This study explores this consonant‐vowel asymmetry in 16‐month‐old infants, using an interactive word learning task. It shows that the pattern of the 16‐month‐olds is the same as that of the 20‐month‐olds. Infants succeeded with 1‐feature consonantal contrasts (either place or voicing) but were at chance level with 1‐feature vocalic contrasts (either place or height). These results thus contribute to a growing body of evidence establishing, from early infancy to adulthood, that consonants and vowels have different roles in lexical acquisition and processing.     

Changes in the Ability to Detect Ordinal Numerical Relationships Between 9 and 11 Months of Age

When are the precursors of ordinal numerical knowledge first evident in infancy? Brannon (2002) argued that by 11 months of age, infants possess the ability to appreciate the greater than and less than relations between numerical values but that this ability experiences a sudden onset between 9 and 11 months of age. Here we present 5 experiments that explore the changes that take place between 9 and 11 months of age in infants' ability to detect reversals in the ordinal direction of a sequence of arrays. In Experiment 1, we replicate the finding that 11‐ but not 9‐month‐old infants detect a numerical ordinal reversal. In Experiment 2 we rule out an alternative hypothesis that 11‐month‐old infants attended to changes in the absolute numerosity of the first stimulus in the sequence rather than a reversal in ordinal direction. In Experiment 3, we demonstrate that 9‐month‐old infants are not aided by additional exposure to each numerosity stimulus in a sequence. In Experiment 4 we find that 11‐month‐old but not 9‐month‐old infants succeed at detecting the reversal in a nonnumerical size or area‐based rule, casting doubt on Brannon's prior claim that what develops between 9 and 11 months of age is a specifically numerical ability. In Experiment 5 we demonstrate that 9‐month‐old infants are capable of detecting a reversal in ordinal direction but only when there are multiple converging cues to ordinality. Collectively these data indicate that at 11 months of age infants can represent ordinal relations that are based on number, size, or cumulative area, whereas at 9 months of age infants are unable to use any of these dimensions in isolation but instead require a confluence of cues.     

The Influence of Maternal Socialization on Infants’ Social Evaluation in Two Cultures

Although a growing body of research has explored the early development of social evaluation, no research has directly compared social evaluations of infants between different cultures. In addition, there has been little understanding regarding socialization's effects on this ability. The goal of this study was to expand on earlier findings on social evaluation in infants by investigating a broader sample from two cultures, and to explore the influence of maternal socialization on infants’ social evaluation. Using the violation of expectations and the preferential reaching paradigm, four groups aged 6‐, 9‐, 12‐, and 15–18 months and their mothers from Japan and the United States (159 dyads) were compared in terms of spontaneous social evaluations. Japanese and European American infants showed similar performance in dishabituation to the inconsistent behavior and in their reaching preference for prosocial over antisocial agents, indicating that the emergence of spontaneous social evaluation is not culture‐specific. Furthermore, our study provides a novel finding regarding the relationship between mothers’ socially evaluative speech and infants’ preference for prosocial over antisocial agents. These results suggest that the development of sociomoral understanding results from complicated interactions among evolutionary, cognitive, and social factors.     

Phonological Specificity in 12‐ and 17‐Month‐Old French‐Speaking Infants

The literature reports some contradictory results on the degree of phonological specificity of infants’ early lexical representations in the Romance language, French, and Germanic languages. It is not clear whether these discrepancies are because of differences in method, in language characteristics, or in participants’ age. In this study, we examined whether 12‐ and 17‐month‐old French‐speaking infants are able to distinguish well‐pronounced from mispronounced words (one or two features of their initial consonant). To this end, 46 infants participated in a preferential looking experiment in which they were presented with pairs of pictures together with a spoken word well pronounced or mispronounced. The results show that both 12‐ and 17‐month‐old infants look longer at the pictures corresponding to well‐pronounced words than to mispronounced words, but show no difference between the two mispronunciation types. These results suggest that, as early as 12 months, French‐speaking infants, like those exposed to Germanic languages, already possess detailed phonological representations of familiar words.     

Distributional Phonetic Learning at 10 Months of Age

Infant phonetic perception reorganizes in accordance with the native language by 10 months of age. One mechanism that may underlie this perceptual change is distributional learning, a statistical analysis of the distributional frequency of speech sounds. Previous distributional learning studies have tested infants of 6–8 months, an age at which native phonetic categories have not yet developed. Here, three experiments test infants of 10 months to help illuminate perceptual ability following perceptual reorganization. English‐learning infants did not change discrimination in response to nonnative speech sound distributions from either a voicing distinction (Experiment 1) or a place‐of‐articulation distinction (Experiment 2). In Experiment 3, familiarization to the place‐of‐articulation distinction was doubled to increase the amount of exposure, and in this case infants began discriminating the sounds. These results extend the processes of distributional learning to a new phonetic contrast, and reveal that at 10 months of age, distributional phonetic learning remains effective, but is more difficult than before perceptual reorganization.     

A Comparison of Visual Familiarization and Object‐Examining Measures of Categorization in 9‐Month‐Old Infants

Three studies were conducted to determine whether differential patterns of categorization observed in studies using visual familiarization and object‐examining measures hold up as procedural confounds are eliminated. In Experiment 1, we attempted as direct a comparison as possible between visual and object‐examining measures of categorization. Consistent with previous reports, 9‐month‐old infants distinguished a basic‐level contrast (dog–horse) in the visual task, but not in the examining task. Experiment 2 was designed to reduce levels of nonexploratory activity in an examining task; 9‐month‐olds again failed to distinguish categories of dogs and horses. In Experiment 3, we adopted a paired‐comparison test format in the object‐examining task. Infants did display a novel category preference under paired testing conditions. The results suggest that the different patterns of categorization often seen in looking and touching tasks are a reflection, not of different categorization processes, but of the differential sensitivity of the tasks.