Infant Learning Research Articles

The cost of selective attention in category learning: Developmental differences between adults and infants

Selective attention plays an important role in category learning. However, immaturities of top-down attentional control during infancy coupled with successful category learning suggest that early category learning is achieved without attending selectively. Research presented here examines this possibility by focusing on category learning in infants (6–8months old) and adults. Participants were trained on a novel visual category. Halfway through the experiment, unbeknownst to participants, the to-be-learned category switched to another category, where previously relevant features became irrelevant and previously irrelevant features became relevant. If participants attend selectively to the relevant features of the first category, they should incur a cost of selective attention immediately after the unknown category switch. Results revealed that adults demonstrated a cost, as evidenced by a decrease in accuracy and response time on test trials as well as a decrease in visual attention to newly relevant features. In contrast, infants did not demonstrate a similar cost of selective attention as adults despite evidence of learning both to-be-learned categories. Findings are discussed as supporting multiple systems of category learning and as suggesting that learning mechanisms engaged by adults may be different from those engaged by infants.

Feedback and imitation by a caregiver guides a virtual infant to learn native phonemes and the skill of speech inversion

Despite large-scale research, development of robust machines for imitation and inversion of human speech into articulatory movements has remained an unsolved problem. We propose a set of principles that can partially explain real infants’ speech acquisition processes and the emergence of imitation skills and demonstrate a simulation where a learning virtual infant (LeVI) learns to invert and imitate a virtual caregiver’s speech. Based on recent findings in infants’ language acquisition, LeVI learns the phonemes of his native language in a babbling phase using only caregiver’s feedback as guidance and to map acoustically differing caregiver’s speech into its own articulation in a phase where LeVI is imitated by the caregiver with similar, but not exact, utterances. After the learning stage, LeVI is able to recognize vowels from the virtual caregiver’s VCVC utterances perfectly and all 25 Finnish phonemes with an average accuracy of 88.42%. The place of articulation of consonants is recognized with an accuracy of 96.81%. LeVI is also able to imitate the caregiver’s speech since the recognition occurs directly in the domain of articulatory programs for phonemes. The learned imitation ability (speech inversion) is strongly language dependent since it is based on the phonemic programs learned from the caregiver. The findings suggest that caregivers’ feedback can act as an important signal in guiding infants’ articulatory learning, and that the speech inversion problem can be effectively approached from the perspective of early speech acquisition.

The power of human gaze on infant learning

Social learning enables infants to acquire information, especially through communication. However, it is unknown whether humans are the prime source of information for infant learning. Here we report that humans have a powerful influence on infants’ object learning compared with nonhuman agents (robots). Twelve-month-old infants were shown videos in which a human or a robot gazed at an object. The results demonstrated that the infants followed the gaze direction of both agents, but only human gaze facilitated their object learning: Infants showed enhanced processing of, and preferences for, the target object gazed at by the human but not by the robot. Importantly, an extended fixation on a target object without the orientation of human gaze did not produce these effects. Together, these findings show the importance of humanness in the gazer, suggesting that infants may be predisposed to treat humans as privileged sources of information for learning.

Imitative Learning of Nso and German Infants at 6 and 9 Months of Age

The present study focused on the assessment of imitation performance in a large sample of 6- and 9-month-old infants from two different cultural contexts: German middle-class infants from urban areas and Nso infants from a rural area in northwestern Cameroon were tested by using age-adapted deferred imitation tasks that were varied regarding their cultural familiarity (two types of instruments each being highly familiar for one of the two cultural contexts). Within both cultural groups and without being influenced by the cultural familiarity of the instruments, infants performed more target actions in the test compared with the baseline phase, even though this difference did not yield significance in the group of 6-month-old Cameroonian Nso infants. Moreover, a higher mean number of imitated actions has been observed for 9-month-olds compared with 6-month-olds demonstrating an age-related improvement of infants’ learning ability. Furthermore, at 9 months of age, German infants showed a higher level of baseline activity compared with the infants in the Cameroonian sample, which is assumed to be based on differences regarding the degree of object experiences. Results provide evidence that early in infancy, imitation is a universal learning tool in different cultural environments.

A biologically constrained architecture for developmental learning of eye–head gaze control on a humanoid robot

In this paper we describe a biologically constrained architecture for developmental learning of eye---head gaze control on an iCub robot. In contrast to other computational implementations, the developmental approach aims to acquire sensorimotor competence through growth processes modelled on data and theory from infant psychology. Constraints help shape learning in infancy by limiting the complexity of interactions between the body and environment, and we use this idea to produce efficient, effective learning in autonomous robots. Our architecture is based on current thinking surrounding the gaze mechanism, and experimentally derived models of stereotypical eye---head gaze contributions. It is built using our proven constraint-based field-mapping approach. We identify stages in the development of infant gaze control, and propose a framework of artificial constraints to shape learning on the robot in a similar manner. We demonstrate the impact these constraints have on learning, and the resulting ability of the robot to make controlled gaze shifts.

Priming infants to use color in an individuation task: Does social context matter?

Infants’ learn a great deal about the physical world during the first year of life. There is a growing body of research investigating the conditions under which this is most likely to occur. Most of this research has focused on the type of information that infants are presented. The current research moves the field in a new direction by investigating the extent to which the social context – who presents the information to the infant – influences knowledge acquisition. Infants were first presented with a color-priming event in a non-social context (Experiment 1) or a social context (Experiment 2). These two contexts differed primarily in whether the individual presenting the color-priming events was behind the apparatus and hidden from view or sat next to the infant and was visible, respectively. The extent to which viewing the color priming events increased infants’ sensitivity to color differences in a subsequent object individuation task was then assessed. The results revealed that whereas 8.5-month-olds experienced color priming in the non-social context, 7.5-month-olds only experienced color priming within a social context. Furthermore, the 7.5-month-olds evidenced priming only when their own parent, not an unfamiliar adult, was the social partner performing the priming events. This provides new evidence for the significance of infant learning within a social context and the potential role of parents.

Word-level information influences phonetic learning in adults and infants

Infants begin to segment words from fluent speech during the same time period that they learn phonetic categories. Segmented words can provide a potentially useful cue for phonetic learning, yet accounts of phonetic category acquisition typically ignore the contexts in which sounds appear. We present two experiments to show that, contrary to the assumption that phonetic learning occurs in isolation, learners are sensitive to the words in which sounds appear and can use this information to constrain their interpretation of phonetic variability. Experiment 1 shows that adults use word-level information in a phonetic category learning task, assigning acoustically similar vowels to different categories more often when those sounds consistently appear in different words. Experiment 2 demonstrates that 8-month-old infants similarly pay attention to word-level information and that this information affects how they treat phonetic contrasts. These findings suggest that phonetic category learning is a rich, interactive process that takes advantage of many different types of cues that are present in the input.

Teaching micro air vehicles how to fly as we teach babies how to walk

Recently, various micro air vehicles have drawn significant attention in numerous areas including surveillance and reconnaissance. The manual control of micro air vehicles is very difficult due to their smaller profile; therefore, a stability and controllability augmentation system is a minimum requirement for stable and efficient flight. However, it is not easy to obtain an accurate numerical model for the flight dynamics of micro air vehicles in the design of the stability and controllability augmentation system. An alternative approach for the stability and controllability augmentation systems is to incorporate reinforcement learning in order to address the numerical complexity. However, in order to train micro air vehicles to learn how to fly, they must first be airborne. This article presents a new method that provides an effective environment where a micro air vehicle can learn to fly in a similar manner to an infant learning to walk. The test setup was constructed to enable the magnetic levitation of a micro air vehicle that has a permanently embedded magnet. This apparatus allows for flexible experimentation: the position and attitude of the micro air vehicle, the constraint forces, and the resulting moments are adjustable and fixable. This “ Pseudo Flight Environment” was demonstrated using a fixed-wing micro air vehicle model. Furthermore, in order for the model to maintain a constant altitude, a height hold control system was devised and implemented.

Infants Are Rational Constructivist Learners

What is the nature of human learning, and what insights can be gained from understanding early learning in infants and young children? This is an important question for understanding the human mind, the origins of knowledge, scientific reasoning, and how to best structure our educational environment. In this article, we argue for a new approach to cognitive development: rational constructivism. This view characterizes the child as a rational constructive learner, and it sees early learning as rational, statistical, and inferential. Empirical evidence for this approach has been accumulating rapidly, and a set of domain-general statistical and inferential mechanisms have been uncovered to explain why infants and young children learn so fast and so well.

Motor contingency learning and infants with Spina Bifida.

Infants with Spina Bifida (SB) were compared to typically developing infants (TD) using a conjugate reinforcement paradigm at 6 months-of-age (n = 98) to evaluate learning, and retention of a sensory-motor contingency. Analyses evaluated infant arm-waving rates at baseline (wrist not tethered to mobile), during acquisition of the sensory-motor contingency (wrist tethered), and immediately after the acquisition phase and then after a delay (wrist not tethered), controlling for arm reaching ability, gestational age, and socioeconomic status. Although both groups responded to the contingency with increased arm-waving from baseline to acquisition, 15% to 29% fewer infants with SB than TD were found to learn the contingency depending on the criterion used to determine contingency learning. In addition, infants with SB who had learned the contingency had more difficulty retaining the contingency over time when sensory feedback was absent. The findings suggest that infants with SB do not learn motor contingencies as easily or at the same rate as TD infants, and are more likely to decrease motor responses when sensory feedback is absent. Results are discussed with reference to research on contingency learning in infants with and without neurodevelopmental disorders, and with reference to motor learning in school-age children with SB.

Neural basis of imprinting behavior in chicks

Newly hatched chicks memorize the characteristics of the first moving object they encounter, and subsequently show a preference for it. This "imprinting" behavior is an example of infant learning and is elicited by visual and/or auditory cues. Visual information of imprinting stimuli in chicks is first processed in the visual Wulst (VW), a telencephalic area corresponding to the mammalian visual cortex, congregates in the core region of the hyperpallium densocellulare (HDCo) cells, and transmitted to the intermediate medial mesopallium (IMM), a region similar to the mammalian association cortex. The imprinting memory is stored in the IMM, and activities of IMM neurons are altered by imprinting. Imprinting also induces functional and structural plastic changes of neurons in the circuit that links the VW and the IMM. Of these neurons, the activity of the HDCo cells is strongly influenced by imprinting. Expression and modulation of NR2B subunit-containing N-methyl-D-aspartate (NMDA) receptors in the HDCo cells are crucial for plastic changes in this circuit as well as the process of visual imprinting. Thus, elucidation of cellular and molecular mechanisms underlying the plastic changes that occurred in the HDCo cells may provide useful knowledge about infant learning.

Examining functional mechanisms of imitative learning in infancy: Does teleological reasoning affect infants’ imitation beyond motor resonance?

Recently, researchers have been debating whether infants’ selective imitative learning is primarily based on sensorimotor processes (e.g., motor resonance through action perception) or whether inferential processes such as teleological reasoning (i.e., reasoning about the efficiency of others’ actions) predominantly explain selective imitation in infancy. The current study directly investigated two different theoretical notions employing the seminal and widely used head touch paradigm. In two conditions, we manipulated whether the action appeared to be efficient while motor resonance was optimized to enhance imitation performance in general. The results showed that infants imitated the target action to the same extent in both conditions irrespective of the action’s efficiency. In addition, in both conditions, more infants imitated the head action than in an additional baseline condition or in a condition where the target action was performed by another effector. The results suggest that 14-month-olds do not imitate novel actions according to their apparent efficiency but that motor resonance is an important factor in infants’ imitation.

Non-adjacent dependency learning in infants at familial risk of dyslexia

This study tests the hypothesis that developmental dyslexia is (partly) caused by a deficit in implicit sequential learning, by investigating whether infants at familial risk of dyslexia can track non-adjacent dependencies in an artificial language. An implicit learning deficit would hinder detection of such dependencies, which mark grammatical relations (e.g. between 'is' and '-ing' in 'she is happily singing'). In a head-turn experiment with infants aged 1;6, family risk and typically developing infants were exposed to one of two novel languages containing dependencies of the type a-X-c, b-X-d or a-X-d, b-X-c, with fixed first and third elements and twenty-four different X elements. During test, typically developing children listened longer to ungrammatical strings (i.e. that did not correspond to their training language). However, family-risk children did not discriminate between grammatical and ungrammatical strings, indicating deficient implicit learning. The implications of these findings in relation to dyslexia and other language-based disorders are discussed.

¿Qué Efecto Tiene Asistir a Sala Cuna y Jardín Infantil Desde los Tres Meses Hasta los Cuatro Años de Edad? Estudio Longitudinal en la Junta Nacional de Jardines Infantiles

This quasi-experimental longitudinal study with comparison group examined the effect on the learning and developmental levels of infants attending the National Preschool Association (JUNJI) nursery schools in Chile (between 3 months and 4 years of age) and the differential effect of attending them from 3 years of age onward. A two-stage (41 nurseries and 427 children at the beginning) and stratified sample by region was used. The comparison group, with similar socioeconomic characteristics (184 children at the beginning), did not attend a nursery school. Children were assessed yearly with the Battelle Developmental Inventory. Family and educational variables were collected using semi-structured interviews and an observational guideline. Comparisons using Propensity Score Matching and Least Squares analysis showed that nearly 80% of the children were learning and developing according to their age, regardless of whether they were attending a JUNJI nursery school or staying at home. Attending from 3 years of age onwards is likely to have positive effects on infant development. The quality of pedagogical practices in babies and family educational attitudes are the most probable explanations for children development.

Quantitative linking hypotheses for infant eye movements.

The study of cognitive development hinges, largely, on the analysis of infant looking. But analyses of eye gaze data require the adoption of linking hypotheses: assumptions about the relationship between observed eye movements and underlying cognitive processes. We develop a general framework for constructing, testing, and comparing these hypotheses, and thus for producing new insights into early cognitive development. We first introduce the general framework – applicable to any infant gaze experiment – and then demonstrate its utility by analyzing data from a set of experiments investigating the role of attentional cues in infant learning. The new analysis uncovers significantly more structure in these data, finding evidence of learning that was not found in standard analyses and showing an unexpected relationship between cue use and learning rate. Finally, we discuss general implications for the construction and testing of quantitative linking hypotheses. MATLAB code for sample linking hypotheses can be found on the first author's website.

The development of associative word learning in monolingual and bilingual infants

Children growing up bilingual face a unique linguistic environment. The current study investigated whether early bilingual experience influences the developmental trajectory of associative word learning, a foundational mechanism for lexical acquisition. Monolingual and bilingual infants (N= 98) were tested on their ability to learn dissimilar-sounding words (lifandneem) in the Switch task. Twelve-month-olds from both language backgrounds failed to detect a violation of a previously taught word–object pairing. However, both monolinguals and bilinguals succeeded at 14 months, and their performance did not differ. The results indicate that early bilingual experience does not interfere with the development of the fundamental ability to form word–object associations, suggesting that this mechanism is robust across different early language environments.

From simple innate biases to complex visual concepts.

Early in development, infants learn to solve visual problems that are highly challenging for current computational methods. We present a model that deals with two fundamental problems in which the gap between computational difficulty and infant learning is particularly striking: learning to recognize hands and learning to recognize gaze direction. The model is shown a stream of natural videos and learns without any supervision to detect human hands by appearance and by context, as well as direction of gaze, in complex natural scenes. The algorithm is guided by an empirically motivated innate mechanism--the detection of "mover" events in dynamic images, which are the events of a moving image region causing a stationary region to move or change after contact. Mover events provide an internal teaching signal, which is shown to be more effective than alternative cues and sufficient for the efficient acquisition of hand and gaze representations. The implications go beyond the specific tasks, by showing how domain-specific "proto concepts" can guide the system to acquire meaningful concepts, which are significant to the observer but statistically inconspicuous in the sensory input.

Frequency of Premature Infant Engagement and Disengagement Behaviors During Two Maternally Administered Interventions

Although sensitive maternal behaviors improve later quality of mother-infant interaction and subsequently infant development, little is known regarding how an intervention might promote early premature infant social interactive behavior. This study compared the frequency of premature infant engagement and disengagement behaviors during two maternally administered interventions, the multisensory auditory, tactile, visual, and vestibular intervention (ATVV) and kangaroo care for 26 infants between 31 and 46 weeks postmenstrual age. The ATVV intervention elicited more disengagement (M = 24 vs 12, P = .0003), trended toward more engagement (M = 21 vs 15.7, P = .06) and more potent engagement (M = 24 vs 12, P = .0003), subtle disengagement (M = 25 vs 11.9, P < .0001), and potent disengagement (M = 22.9 vs 14, P = .006) behaviors than did kangaroo care. The ATVV intervention may be an intervention to promote the infant's learning how to regulate engagement and disengagement behaviors.

Electrophysiological Evidence for the Understanding of Maternal Speech by 9-Month-Old Infants

Early word learning in infants relies on statistical, prosodic, and social cues that support speech segmentation and the attachment of meaning to words. It is debated whether such early word knowledge represents mere associations between sound patterns and visual object features, or reflects referential understanding of words. By measuring an event-related brain potential component known as the N400, we demonstrated that 9-month-old infants can detect the mismatch between an object appearing from behind an occluder and a preceding label with which their mother introduces it. Differential N400 amplitudes have been shown to reflect semantic priming in adults, and its absence in infants has been interpreted as a sign of associative word learning. By setting up a live communicative situation for referring to objects, we demonstrated that a similar priming effect also occurs in young infants. This finding may indicate that word meaning is referential from the outset of word learning and that referential expectation drives, rather than results from, vocabulary acquisition in humans.

Neurocognitive mechanisms underlying social learning in infancy: infants' neural processing of the effects of others' actions.

Social transmission of knowledge is one of the reasons for human evolutionary success, and it has been suggested that already human infants possess eminent social learning abilities. However, nothing is known about the neurocognitive mechanisms that subserve infants' acquisition of novel action knowledge through the observation of other people's actions and their consequences in the physical world. In an electroencephalogram study on social learning in infancy, we demonstrate that 9-month-old infants represent the environmental effects of others' actions in their own motor system, although they never achieved these effects themselves before. The results provide first insights into the neurocognitive basis of human infants' unique ability for social learning of novel action knowledge.