Preverbal Infants Research Articles

Preverbal infants' sensitivity to grammatical dependencies.

During their first months of life, infants can already distinguish function words (e.g., pronouns and determiners) from content words (e.g., verbs and nouns). Little research has explored preverbal infants' sensitivity to the relationships between these word categories. This preregistered study examines whether French-learning 8- and 11-month-olds track the grammatical dependencies between determiners and nouns as well as pronouns and verbs. Using the Visual Fixation Procedure, infants were presented with lists containing either grammatical (e.g., tu manges "you eat", des biberons "some bottles") or ungrammatical (e.g., des manges "some eat", tu biberons "you bottle") phrases. In Experiment 1 (N=59), the lists involved common nouns and verbs, while in Experiment 2 (N=28), only common verbs were used. Eleven-month-olds showed a clear preference for correct over incorrect co-occurrences in both experiments, while 8-month-olds showed a trend in the same direction. These results suggest that before their first birthday, infants' storage and access of words and word sequences are sufficiently sophisticated to include the means to track categorical dependencies. This early sensitivity to co-occurrence patterns may be greatly beneficial for constraining lexical access and later on for learning novel words' syntactic and semantic properties.

Minor second intervals: A shared signature for infant cries and sadness in music.

In Western music and in music of other cultures, minor chords, modes and intervals evoke sadness. It has been proposed that this emotional interpretation of melodic intervals (the distance between two pitches, expressed in semitones) is common to music and vocal expressions. Here, we asked expert musicians to transcribe into music scores spontaneous vocalizations of pre-verbal infants to test the hypothesis that melodic intervals that evoke sadness in music (i.e., minor 2nd) are more represented in cry compared to neutral utterances. Results showed that the unison, major 2nd, minor 2nd, major 3rd, minor 3rd, perfect 4th and perfect 5th are all represented in infant vocalizations. However, minor 2nd outnumbered all other intervals in cry vocalizations, but not in neutral babbling. These findings suggest that the association between minor intervals and sadness may develop in humans because a critically relevant social cue (infant cry) contains a statistical regularity: the association between minor 2nd and negative emotional valence.

Moral masters or moral apprentices? A connectionist account of sociomoral evaluation in preverbal infants

Numerous studies suggest that preverbal infants possess the ability to make sociomoral judgements and demonstrate a preference for prosocial agents. Some theorists argue that infants possess an “innate moral core” that guides their sociomoral reasoning. However, we propose that infants’ capacity for putative sociomoral evaluation and reasoning can just as likely be driven by a domain-general associative-learning mechanism that is sensitive to agent action. We implement this theoretical account in a connectionist computational model and show that it can account for the pattern of results in Hamlin et al. (2007), Hamlin and Wynn (2011), Hamlin (2013), and Hamlin, Wynn, Bloom, and Mahajan (2011). These are pioneering studies in this area and were among the first to examine sociomoral evaluation in preverbal infants. Based on the results of 9 computer simulations, we suggest that an associative-learning mechanism—instantiated as a computational (connectionist) model—can account for previous findings on preverbal infants’ capacity for sociomoral evaluation. These results suggest that an innate moral core may not be necessary to account for sociomoral evaluation in infants.

Visual perception grounding of social cognition in preverbal infants

Social life is inherently relational, entailing the ability to recognize and monitor social entities and the relationships between them. Very young infants privilege socially relevant entities in the visual world, such as faces and bodies. Here, we show that six-month-old infants also discriminate between configurations of multiple human bodies, based on the internal visuo-spatial relations between bodies, which could cue-or not-social interaction. We measured the differential looking times for two images, each featuring two identical bodies, but in different spatial relations. Infants discriminated between face-to-face and back-to-back body dyads (Experiment 1), and treated face-to-face dyads with higher efficiency (i.e., processing speed), relative to back-to-back dyads (Experiment 2). Looking times for dyads in an asymmetrical relation (i.e., one body facing another without reciprocation) were comparable to looking times for face-to-face dyads, and differed from looking times to back-to-back dyads, suggesting general discrimination between the presence versus absence of relation (Experiment 3). Infants' discrimination of images based on relative positioning of items did not generalize to body-object pairs (Experiment 4). Early sensitivity to the relative positioning of bodies in a scene may be a building block of social cognition, preparing the discovery of the keel and backbone of social life: relations.

Mechanisms of social evaluation in infancy: A preregistered exploration of infants' eye-movement and pupillary responses to prosocial and antisocial events.

Past research shows infants selectively touch and look longer at characters who help versus hinder others (Social evaluation by preverbal infants. Nature, 2007, 450, 557; Three-month-olds show a negativity bias in their social evaluations. Developmental Science, 2010, 13, 923); however, the mechanisms underlying this tendency remain underspecified. The current preregistered experiment approaches this question by examining infants' real-time looking behaviors during prosocial and antisocial events, and exploring how individual infants' looking behaviors correlate with helper preferences. Using eye-tracking, 34 five-month-olds were familiarized with two blocks of the "hill" scenario originally developed by Kuhlmeier et al. (Attribution of dispositional states by 12-month-olds. Psychological Science, 2003, 14, 402), in which a climber tries unsuccessfully to reach the top of a hill and is alternately helped or hindered. Infants' visual preferences were assessed after each block of 6helping and hindering events by proportional looking time to the helper versus hinderer in an image of the characters side by side. Results showed that, at the group level, infants looked longer at the helper after viewing 12 (but not after viewing 6) helping and hindering videos. Moreover, individual infants' average preference for the helper was predicted by their looking behaviors, particularly those suggestive of an understanding of the climber's unfulfilled goal. These results shed light on how infants process helping/hindering scenarios, and suggest that goal understanding is important for infants' helper preferences.

Acoustic signatures of communicative dimensions in codified mother-infant interactions.

Nursery rhymes, lullabies, or traditional stories are pieces of oral tradition that constitute an integral part of communication between caregivers and preverbal infants. Caregivers use a distinct acoustic style when singing or narrating to their infants. Unlike spontaneous infant-directed (ID) interactions, codified interactions benefit from highly stable acoustics due to their repetitive character. The aim of the study was to determine whether specific combinations of acoustic traits (i.e., vowel pitch, duration, spectral structure, and their variability) form characteristic "signatures" of different communicative dimensions during codified interactions, such as vocalization type, interactive stimulation, and infant-directedness. Bayesian analysis, applied to over 14 000 vowels from codified live interactions between mothers and their 6-months-old infants, showed that a few acoustic traits prominently characterize arousing vs calm interactions and sung vs spoken interactions. While pitch and duration and their variation played a prominent role in constituting these signatures, more linguistic aspects such as vowel clarity showed small or no effects. Infant-directedness was identifiable in a larger set of acoustic cues than the other dimensions. These findings provide insights into the functions of acoustic variation of ID communication and into the potential role of codified interactions for infants' learning about communicative intent and expressive forms typical of language and music.

Violations of expectation trigger infants to search for explanations

Infants look longer and explore more following violations-of-expectation, but the reasons for these surprise-induced behaviors are unclear. One possibility is that expectancy violations heighten arousal generally, thereby increasing infants’ post-surprise activity. Another possibility is that infants’ exploration reflects the search for an explanation for the surprising event. We tested these alternatives in three experiments. First in Experiment 1 we confirmed that seeing an object violate expectations (by passing through a solid wall) increased infants’ exploration of the surprising object, relative to when no expectancy violation was seen. Then in Experiment 2 we measured infants’ exploration after they had seen the same violation event, but then an explanation for the event was provided (the wall was revealed to have a large hole in it). We found that providing this explanation abolished infants’ surprise-induced exploration. In Experiment 3 we replicated this effect. Furthermore, we found that the longer infants looked at the explanation, the greater their reversal in exploratory preference (i.e., the more they ignored the surprising object). These findings demonstrate that preverbal infants both seek and recognize explanations for surprising events.

Speech perception and the sensorimotor system in Infancy

The speech that infants perceive and learn from is highly multisensory. Preverbal infants show multisensory speech sensitivities prior to direct associative experience, for instance, even to non-native speech that they have not experienced before. Sensorimotor influences on auditory perception are of increasing interest in the context of speech perception development. In a series of experiments, we explored whether infants’ speech perception is influenced by articulatory-auditory relations. Specifically, we experimentally restricted the movement of infants’ relevant articulators during speech perception tasks. We review a series of studies showing both behavioral (eye-tracking) and neural (EEG) evidence that preverbal infants’ auditory speech perception is influenced by articulatorily specific sensorimotor input at 6- and 3- months of age. To control for the possibility of learning, we tested both native and non-native (hence not visually nor auditorily familiar) phonetic contrasts. To explore whether the auditory-sensorimotor relation is in place even without feedback from self-produced vocalization, we tested consonant discrimination in infants as young as 3-month, who are not yet babbling and are unable to produce consonant sounds. Our results show that the sensorimotor-auditory link is in place prior to specific experience watching, hearing, or producing the relevant sounds.

Disjunctive inference in preverbal infants

SummaryCan preverbal infants utilize logical reasoning such as disjunctive inference? This logical operation requires keeping two alternatives open (A or B), until one of them is eliminated (if not A), allowing the inference: B is true. We presented to 10-month-old infants an ambiguous situation in which a female voice was paired with two faces. Subsequently, one of the two faces was presented with the voice of a male. We measured infants' preference for the correct face when both faces and the initial voice were presented again. Infant pupillary response was measured and utilized as an indicator of cognitive load at the critical moment of disjunctive inference. We controlled for other possible explanations in three additional experiments. Our results show that 10-month-olds can correctly deploy disjunction and negation to disambiguate scenes, suggesting that disjunctive inference does not rely on linguistic constructs.

Quantifying Voice Characteristics for Detecting Autism.

The presence of prosodic anomalies in autistic is recognized by experienced clinicians but their quantitative analysis is a cumbersome task beyond the scope of typical pen and pencil assessment. This paper proposes an automatic approach allowing to tease apart various aspects of prosodic abnormalities and to translate them into fine-grained, automated, and quantifiable measurements. Using a harmonic model (HM) of voiced signal, we isolated the harmonic content of speech and computed a set of quantities related to harmonic content. Employing these measures, along with standard speech measures such as loudness, we successfully trained machine learning models for distinguishing individuals with autism from those with typical development (TD). We evaluated our models empirically on a task of detecting autism on a sample of 118 youth (90 diagnosed with autism and 28 controls; mean age: 10.9 years) and demonstrated that these models perform significantly better than a chance model. Voice and speech analyses could be incorporated as novel outcome measures for treatment research and used for early detection of autism in preverbal infants or toddlers at risk of autism.

Pre-verbal Children's Participation in a New Key. How Intersubjectivity Can Contribute to Understanding and Implementation of Child Rights in Early Childhood.

Children’s participation and involvement has increasingly been on the agenda for the last few decades. The right for children to participate was established in the United Nations Convention on the Rights of the Child (UNCRC). However, even though the UNCRC gives the right to participate to all children, national policy and practice seems to draw a line on verbal language and exclude pre-verbal infants from participation. The spur of this paper is to challenge the exclusion of infants, to describe how pre-linguistic children communicate their intentions, and to show how an understanding of children’s participation grounded in intersubjectivity, can inform and reframe the participation of all children as being fundamentally about close relationships with sensitive and containing adults who look within themselves for the voice of the child. The infant’s proto-conversational narrative communicates interests and feelings through sympathetic rhythms of what infant researchers have named “communicative musicality,” and it can surface in the mother’s narrative about the child and their relationship. Intersubjectivity oppose the monadic view of man as separate and left only to imitate others and claims that humans from the very start are intertwined in a fundamental thirdness of co-created reality. Infants are powerful communicators who actively engage in intersubjective relationships with their caretakers only days after birth, and newborns actively influence and even control the mental process of those who communicate with them. Early childhood participation then, would be to find within ourselves the voice of the child. A research project building on the theories and ideas described in the first part of the article, is presented.

Orthogonal neural codes for speech in the infant brain

Creating invariant representations from an everchanging speech signal is a major challenge for the human brain. Such an ability is particularly crucial for preverbal infants who must discover the phonological, lexical, and syntactic regularities of an extremely inconsistent signal in order to acquire language. Within the visual domain, an efficient neural solution to overcome variability consists in factorizing the input into a reduced set of orthogonal components. Here, we asked whether a similar decomposition strategy is used in early speech perception. Using a 256-channel electroencephalographic system, we recorded the neural responses of 3-mo-old infants to 120 natural consonant-vowel syllables with varying acoustic and phonetic profiles. Using multivariate pattern analyses, we show that syllables are factorized into distinct and orthogonal neural codes for consonants and vowels. Concerning consonants, we further demonstrate the existence of two stages of processing. A first phase is characterized by orthogonal and context-invariant neural codes for the dimensions of manner and place of articulation. Within the second stage, manner and place codes are integrated to recover the identity of the phoneme. We conclude that, despite the paucity of articulatory motor plans and speech production skills, pre-babbling infants are already equipped with a structured combinatorial code for speech analysis, which might account for the rapid pace of language acquisition during the first year.

Infants exploit vowels to label objects and actions from continuous audiovisual stimuli

Before the 6-months of age, infants succeed to learn words associated with objects and actions when the words are presented isolated or embedded in short utterances. It remains unclear whether such type of learning occurs from fluent audiovisual stimuli, although in natural environments the fluent audiovisual contexts are the default. In 4 experiments, we evaluated if 8-month-old infants could learn word-action and word-object associations from fluent audiovisual streams when the words conveyed either vowel or consonant harmony, two phonological cues that benefit word learning near 6 and 12 months of age, respectively. We found that infants learned both types of words, but only when the words contained vowel harmony. Because object- and action-words have been conceived as rudimentary representations of nouns and verbs, our results suggest that vowels contribute to shape the initial steps of the learning of lexical categories in preverbal infants.

Preverbal infants expect agents exhibiting counterintuitive capacities to gain access to contested resources

Claims to supernatural power have been used as a basis for authority in a wide range of societies, but little is known about developmental origins of the link between supernatural power and worldly authority. Here, we show that 12- to 16-month-old infants expect agents exhibiting counterintuitive capacities to win out in a two-way standoff over a contested resource. Infants watched two agents gain a reward using either physically intuitive or physically counterintuitive methods, the latter involving simple forms of levitation or teleportation. Infants looked longer, indicating surprise, when the physically intuitive agent subsequently outcompeted a physically counterintuitive agent in securing a reward. Control experiments indicated that infants’ expectations were not simply motived by the efficiency of agents in pursuing their goals, but specifically the deployment of counterintuitive capacities. This suggests that the link between supernatural power and worldly authority has early origins in development.

Attentional blink in preverbal infants

Primary cognitive processes, such as spatial attention, are essential to our higher cognitive abilities and develop dramatically in the first year of life. The spatial aspect of infants' working memory is equivalent to that of adults. However, it is unclear whether this is true for the temporal domain. Thus, we investigated the temporal aspect of infants' working memory using an attentionally demanding task by focusing on the attentional blink effect, in which the identification of the second of the two brief targets is impaired when inter-target lags are short. We argue that finding a similar pattern of the attentional blink in preverbal infants and adults indicates that infants can complete the consolidation of the first target into working memory at a similar temporal scale as adults. In this experiment, we presented 7- to 8-month-old infants with rapid serial visual streams at a rate of 100 ms/item, including two female faces as targets, and examined whether they could identify the targets by measuring their preference to novel faces compared to targets. The temporal separation between the two targets was 200 or 800 ms. We found that the infants could identify both targets under the longer lag, but they failed to identify the second target under the shorter lag. The adult experiment using the same temporal separation as in the infant experiment revealed the attentional blink effect. These results suggest that 7- to 8-month-old infants can consolidate two items into working memory by 800 ms but not by 200 ms.

Three-year-olds’ spontaneous lying in a novel interaction-based paradigm and its relations to explicit skills and motivational factors

Previous research has investigated children’s lying and its motivational and social-cognitive correlates mostly through explicit tasks. The current study used an anticipatory interaction-based paradigm adopted from research with preverbal infants. We investigated 3-year-olds’ spontaneous lying within interaction and its motivational basis and relations to explicit skills of lying, false belief understanding, inhibitory control, and socialization. Children interacted with puppets to secure stickers that were hidden in one of two boxes. Either a friend or a competitor puppet tried to obtain the stickers. Nearly all children helpfully provided information about the sticker’s location to the friend, and about half of the sample anticipatorily provided false information to the competitor. Children misinformed the competitor significantly more often than the friend, both when the reward was for themselves and when it was for someone else. Explicitly planning to lie in response to a question occurred significantly less often but predicted spontaneous lying, as did passing the explicit standard false belief task. Thus, by 3 years of age, children spontaneously invoke false beliefs in others. This communicative skill reveals an interactional use of false belief understanding in that it requires holding one’s perspective to pursue one’s goal while providing a different perspective to distract a competitor. Findings support the view that practical theory of mind skills emerge for social coordination and serve as a basis for developing explicit false belief reasoning.

Nonverbal category knowledge limits the amount of information encoded in object representations: EEG evidence from 12-month-old infants.

To what extent does language shape how we think about the world? Studies suggest that linguistic symbols expressing conceptual categories (‘apple’, ‘squirrel’) make us focus on categorical information (e.g. that you saw a squirrel) and disregard individual information (e.g. whether that squirrel had a long or short tail). Across two experiments with preverbal infants, we demonstrated that it is not language but nonverbal category knowledge that determines what information is packed into object representations. Twelve-month-olds (N = 48) participated in an electroencephalography (EEG) change-detection task involving objects undergoing a brief occlusion. When viewing objects from unfamiliar categories, infants detected both across- and within-category changes, as evidenced by their negative central wave (Nc) event-related potential. Conversely, when viewing objects from familiar categories, they did not respond to within-category changes, which indicates that nonverbal category knowledge interfered with the representation of individual surface features necessary to detect such changes. Furthermore, distinct patterns of γ and α oscillations between familiar and unfamiliar categories were evident before and during occlusion, suggesting that categorization had an influence on the format of recruited object representations. Thus, we show that nonverbal category knowledge has rapid and enduring effects on object representation and discuss their functional significance for generic knowledge acquisition in the absence of language.

Explicit access to phonetic representations in 3-month-old infants

Preverbal infants are particularly good at discriminating syllables that differ by a single phoneme but do they perceive syllables as a whole unit or can they become aware of the underlying phonemes if their attention is attracted to the relevant level of analysis? We trained 3-month-old infants to pair two consonants, co-articulated with different vowels, with two visual shapes. Using event-related potentials, we showed that infants generalize the learned associations to new syllables with respect to the training phase. The systematic pairing of a visual label with a phonetic category is rapidly learned in a few trials, suggesting that phonemes are natural categories for infants but also that phonetic representations are accessible to internal operations outside the linguistic system. Hence, the possibility of an explicit access to the phonetic level, which is the main process underlying alphabetic reading system, is grounded in the early faculties of the human infant.

Disjunctive Inference in Preverbal Infants

Can preverbal infants already use logical reasoning such as disjunctive inference? This reasoning requires keeping two possibilities open (A or B), until one of them is eliminated (if not A), allowing the inference: B is true. We used a paradigm based on 10-month-olds’ social skills and their ability to pair face and voice: We first presented an ambiguous situation: a female voice and two faces, then one of the faces was presented with a male voice implying that the initial voice belonged to the other face. We measured infants’ preference for the correct face when both faces and the initial voice were again presented, as well as infants’ pupillary response, as an indicator of cognitive load at the critical moment of disjunctive inference. We controlled for other possible explanations in 3 additional experiments. Our results show that 10-month-olds can correctly deploy disjunction and negation to disambiguate scenes, suggesting that disjunctive inference does not rely on linguistic constructs.

Indian association of paediatric anaesthesia advisory for pain management in neonates and preverbal children

In the past, management of pain in neonates was regarded as unnecessary, with the belief that neonates have an immature nervous system and do not perceive pain. Later studies confirmed that neonates certainly do feel pain, though they lack the inhibitory mechanisms that modulate excruciating stimuli, unlike in older children. Repeated painful encounters experienced in the newborn period are associated with poor cognitive and motor development by 1 year of age. Pain in preverbal infants and children is also poorly recognized and often undertreated. Neonates and preverbal children cannot verbally communicate their pain and discomfort but express them through specific behavioral, physiological, and biochemical responses. Several pain measurement tools have been developed for young children as surrogate measures of pain. To achieve optimum postoperative or procedural pain relief, easily understandable tools and a multimodal treatment module should be tailor-made for each health-care facility that cares for neonates and young infants. The aim of this advisory is to outline key concepts of pain assessment in neonates and preverbal children and suggest a rational approach to its management by all anesthesiologists, pediatricians, nursing staff, and other medical personnel caring for these children. The Indian Association of Paediatric Anaesthesia (IAPA) convened an online meeting in April 2020 to formulate the advisory on pain management in neonates and preverbal children under the chairmanship of Dr. Elsa Varghese, President IAPA, and members of the guideline committee. After several such meetings and revisions using feedback from IAPA members, the final guidelines were released in October 2020 on the IAPA website. Recommendations: Pain relief should generally be accomplished with a combination of nonpharmacologic approaches and pharmacologic techniques in a stepwise tiered manner by escalating type and dose of analgesia with anticipated increases in procedural pain. Nonpharmacological distraction measures may be sufficient for minor needle procedures like vaccination and venipuncture and may be offered as a first step and to complement other pain management remedies. An interdisciplinary approach involving pharmacologic, cognitive-behavioral, psychologic, and physical treatments should be employed whenever feasible.