Infants' perception of goal‐directed actions on video

Imitation studies and object search studies show that infants have difficulties using action information presented on video to guide their own behaviour. The present study investigated whether infants also have problems interpreting information shown on video relative to real live information. It was examined whether 6‐month‐olds interpret an action with a salient action effect as goal‐directed when it is performed by an actor on a video‐screen and when it is performed by a live actor. A video presentation of a goal‐directed action display was presented to one group of infants, and another group received the same action display, matched in all details, live on a stage. Results indicate that 6‐month‐olds in the video group as well as in the live group interpreted the human action as goal‐directed. Moreover, comparison across both groups revealed no difference in the overall looking pattern between the video and the live presentation group. Thus, our findings show that infants as young as 6 months of age can take important information from video clips and interpret televised actions in meaningful ways that is equivalent to their interpretation of live actions.     

Specialization of the motor system in infancy: from broad tuning to selectively specialized purposeful actions

In executing purposeful actions, adults select sufficient and necessary limbs. But infants often move goal‐irrelevant limbs, suggesting a developmental process of motor specialization. Two experiments with 9‐ and 12‐month‐olds revealed gradual decreases in extraneous movements in non‐acting limbs during unimanual actions. In Experiment 1, 9‐month‐olds produced more extraneous movements in the non‐acting hand/arm and feet/legs than 12‐month‐olds. In Experiment 2, analysis of the spatiotemporal dynamics of infants’ movements revealed developmental declines in the spatiotemporal coupling of movements between acting and non‐acting arms. We also showed that the degree of specialization in infants’ unimanual actions is associated with individual differences in motor experience and visual attention, indicating the experience‐dependent and broad functional nature of these developmental changes. Our study provides important new insights into motor development: as in cognitive domains, motor behaviours are initially broadly tuned to their goal, becoming progressively specialized during the first year of life.     

Object individuation and event mapping: developmental changes in infants’ use of featural information

The present research examined the development of 4.5‐ to 7.5‐month‐old infants’ ability to map different‐features occlusion events using a simplified event‐mapping task. In this task, infants saw a different‐features (i.e. egg‐column) event followed by a display containing either one object or two objects. Experiments 1 and 2 assessed infants’ ability to judge whether the egg‐column event was consistent with a subsequent one‐column display. Experiments 3 and 4 examined infants’ ability to judge whether the objects seen in the egg‐column event and those seen in a subsequent display were consistent in their featural composition. At 7.5 and 5.5 months, but not at 4.5 months, the infants successfully mapped the egg‐column event onto the one‐column display. However, the 7.5‐ and 5.5‐month‐olds differed in whether they mapped the featural properties of those objects. Whereas the 7.5‐month‐olds responded as if they expected to see two specific objects, an egg and a column, in the final display the 5.5‐month‐olds responded as if they simply expected to see ‘two objects’. Additional results revealed, however, that when spatiotemporal information specified the presence of two objects, 5.5‐month‐olds succeeded at tagging the objects as being featurally distinct, although they still failed to attach more specific information about what those differences were. Reasons for why the younger infants had difficulty integrating featural information into their object representations were discussed.     

Imitation from television by 24‐ and 30‐month‐olds

Infants’ imitation of complex actions was examined in three experiments with 24‐ and 30‐month‐olds. In all experiments, an adult modeled a series of actions with novel stimuli and the infant's reproduction of those actions was assessed either immediately or after a 24‐hour delay. Some infants watched the demonstration live, while other infants watched the same demonstration on television from a pre‐recorded videotape. Both 24‐ and 30‐month‐olds imitated actions that had been modeled on television; however, their performance was consistently inferior to that of infants of the same age who watched the demonstration live.     

Eighteen- and 24-month-old infants correct others in anticipation of action mistakes

Much of human communication and collaboration is predicated on making predictions about others' actions. Humans frequently use predictions about others' action mistakes to correct others and spare them mistakes. Such anticipatory correcting reveals a social motivation for unsolicited helping. Cognitively, it requires forward inferences about others' actions through mental attributions of goal and reality representations. The current study shows that infants spontaneously intervene when an adult is mistaken about the location of an object she is about to retrieve. Infants pointed out a correct location for an adult before she was about to commit a mistake. Infants did not intervene in control conditions when the adult had witnessed the misplacement, or when she did not intend to retrieve the misplaced object. Results suggest that preverbal infants anticipate a person's mistaken action through mental attributions of both her goal and reality representations, and correct her proactively by spontaneously providing unsolicited information.     

From outcome prediction to action selection: developmental change in the role of action–effect bindings

Ideomotor theory considers bidirectional action–effect associations to be the fundamental building blocks for intentional action. The present study employed a novel pupillometric and oculomotor paradigm to study developmental changes in the role of action‐effects in the acquisition of voluntary action. Our findings suggest that both 7‐ and 12‐month‐olds (and adults) can use acquired action–effect bindings to predict action outcomes but only 12‐month‐olds (and adults) showed evidence for employing action‐effects to select actions. This dissociation supports the idea that infants acquire action–effect knowledge before they have developed the cognitive machinery necessary to make use of that knowledge to perform intentional actions.     

One‐year‐old infants use teleological representations of actions productively

Two experiments investigated whether infants represent goal‐directed actions of others in a way that allows them to draw inferences to unobserved states of affairs (such as unseen goal states or occluded obstacles). We measured looking times to assess violation of infants' expectations upon perceiving either a change in the actions of computer‐animated figures or in the context of such actions. The first experiment tested whether infants would attribute a goal to an action that they had not seen completed. The second experiment tested whether infants would infer from an observed action the presence of an occluded object that functions as an obstacle. The looking time patterns of 12‐month‐olds indicated that they were able to make both types of inferences, while 9‐month‐olds failed in both tasks. These results demonstrate that, by the end of the first year of life, infants use the principle of rational action not only for the interpretation and prediction of goal‐directed actions, but also for making productive inferences about unseen aspects of their context. We discuss the underlying mechanisms that may be involved in the developmental change from 9 to 12 months of age in the ability to infer hypothetical (unseen) states of affairs in teleological action representations.     

Mother versus stranger: a triadic situation of imitation at the end of the first year of life

This study presents two experiments investigating 8‐ and 12‐month‐old infants' imitative behaviour. Seventy‐two 8‐month‐olds and seventy‐two 12‐month‐olds were observed in a triadic situation which included their mother and a stranger. Depending on the condition, either the mother or the stranger acted as the demonstrator and either stayed close or withdrew after the demonstration, during the response period. In addition to imitative acts, visual exploration and smiles addressed, respectively, to each partner were computed. Results showed that at both ages, neither the familiarity nor the position of the partner has an effect on the number of target gestures that are imitated. At 12 months, infants looked and smiled more at the stranger when he demonstrated target actions but no difference was found when the mother acted as demonstrator. Moreover, 12‐month‐old infants looked more at the demonstrating partner immediately after their first imitation. At 8 months, infants paid more attention to the stranger in all conditions except when the mother performed the target actions and moved away, a pattern that suggests a referencing to the mother. Results from the gaze and smile variables suggest that with age different motivations (social contact, exploration of objects) induce imitation. Copyright © 2003 John Wiley & Sons, Ltd.     

Delayed Match Retrieval: a novel anticipation‐based visual working memory paradigm

We tested 8‐ and 10‐month‐old infants’ visual working memory (VWM) for object‐location bindings – what is where – with a novel paradigm, Delayed Match Retrieval, that measured infants’ anticipatory gaze responses (using a Tobii T120 eye tracker). In an inversion of Delayed‐Match‐to‐Sample tasks and with inspiration from the game Memory, in test trials, three face‐down virtual ‘cards’ were presented. Two flipped over sequentially (revealing, e.g. a swirl pattern and then a star), and then flipped back face‐down. Next, the third card was flipped to reveal a match (e.g. a star) to one of the previously seen, now face‐down cards. If infants looked to the location where the (now face‐down) matching card had been shown, this was coded as a correct response. To encourage anticipatory looks, infants subsequently received a reward (a brief, engaging animation) presented at that location. Ten‐month‐old infants performed significantly above chance, showing that their VWM could hold object‐location information for the two cards. Overall, 8‐month‐olds’ performance was at chance, but they showed a robust learning trend. These results corroborate previous findings (Kaldy & Leslie, 2005; Oakes, Ross‐Sheehy & Luck, 2006) and point to rapid development of VWM for object‐location bindings. However, compared to previous paradigms that measure passive gaze responses to novelty, this paradigm presents a more challenging, ecologically relevant test of VWM, as it measures the ability to make online predictions and actively localize objects based on VWM. In addition, this paradigm can be readily scaled up to test toddlers or older children without significant modification.     

The mentalistic basis of core social cognition: experiments in preverbal infants and a computational model

Evaluating individuals based on their pro‐ and anti‐social behaviors is fundamental to successful human interaction. Recent research suggests that even preverbal infants engage in social evaluation; however, it remains an open question whether infants’ judgments are driven uniquely by an analysis of the mental states that motivate others’ helpful and unhelpful actions, or whether non‐mentalistic inferences are at play. Here we present evidence from 10‐month‐olds, motivated and supported by a Bayesian computational model, for mentalistic social evaluation in the first year of life.A video abstract of this article can be viewed at http://youtu.be/rD_Ry5oqCYE     

Ten‐month‐old infants use prior information to identify an actor's goal

For adults, prior information about an individual's likely goals, preferences or dispositions plays a powerful role in interpreting ambiguous behavior and predicting and interpreting behavior in novel contexts. Across two studies, we investigated whether 10‐month‐old infants’ ability to identify the goal of an ambiguous action sequence was facilitated by seeing prior instances in which the actor directly pursued and obtained her goal, and whether infants could use this prior information to understand the actor's behavior in a new context. Experiment 1 demonstrated that the goal preview impacted infants’ subsequent action understanding, but only if the preview was delivered in the same room as the subsequent action sequence. Experiment 2 demonstrated that infants’ failure to transfer prior goal information across situations arose from a change in the room per se and not other features of the task. Our results suggest that infants may use their understanding of simple actions as a leverage point for understanding novel or ambiguous actions, but that their ability to do so is limited to certain types of contextual changes.     

Increasing task difficulty enhances effects of intersensory redundancy: testing a new prediction of the Intersensory Redundancy Hypothesis

Prior research has demonstrated intersensory facilitation for perception of amodal properties of events such as tempo and rhythm in early development, supporting predictions of the Intersensory Redundancy Hypothesis (IRH). Specifically, infants discriminate amodal properties in bimodal, redundant stimulation but not in unimodal, nonredundant stimulation in early development, whereas later in development infants can detect amodal properties in both redundant and nonredundant stimulation. The present study tested a new prediction of the IRH: that effects of intersensory redundancy on attention and perceptual processing are most apparent in tasks of high difficulty relative to the skills of the perceiver. We assessed whether by increasing task difficulty, older infants would revert to patterns of intersensory facilitation shown by younger infants. Results confirmed our prediction and demonstrated that in difficult tempo discrimination tasks, 5‐month‐olds perform like 3‐month‐olds, showing intersensory facilitation for tempo discrimination. In contrast, in tasks of low and moderate difficulty, 5‐month‐olds discriminate tempo changes in both redundant audiovisual and nonredundant unimodal visual stimulation. These findings indicate that intersensory facilitation is most apparent for tasks of relatively high difficulty and may therefore persist across the lifespan.     

Infants’ developing understanding of the link between looker and object

Three studies investigated infants’ understanding that gaze involves a relation between a person and the object of his or her gaze. Infants were habituated to an event in which an actor turned and looked at one of two toys. Then, infants saw test events in which (1) the actor turned to the same side as during habituation to look at a different toy, or (2) the actor turned to the other side to look at the same toy as during habituation. The first of these involved a change in the relation between actor and object. The second involved a new physical motion on the part of the actor but no change in the relation between actor and object. Seven‐ and 9‐month‐old infants did not respond to the change in relation between actor and object, although infants at both ages followed the actor's gaze to the toys. In contrast, 12‐month‐old infants responded to the change in the actor–object relation. Control conditions verified that the paradigm was a sensitive index of the younger infants’ representations of action: 7‐ and 9‐month‐olds responded to a change in the actor–object relation when the actor's gaze was accompanied by a grasp. Taken together, these findings indicate that gaze‐following does not initially go hand in hand with understanding the relation between a person who looks and the object of his or her gaze, and that infants begin to understand this relation between 9 and 12 months.     

Perceptual narrowing towards adult faces is a cross‐cultural phenomenon in infancy: a behavioral and near‐infrared spectroscopy study with Japanese infants

Recent data showed that, in Caucasian infants, perceptual narrowing occurs for own‐race adult faces between 3 and 9 months of age, possibly as a consequence of the extensive amount of social and perceptual experience accumulated with caregivers and/or other adult individuals of the same race of the caregiver. The neural correlates of this developmental process remain unexplored, and it is currently unknown whether perceptual tuning towards adult faces can be extended to other cultures. To this end, in the current study we tested the ability of 3‐ and 9‐month‐old Japanese infants to discriminate among adult and infant Asian faces in a visual familiarization task (Experiment 1), and compared 9‐month‐olds’ cerebral hemodynamic responses to adult and infant faces as measured by near‐infrared spectroscopy (NIRS) (Experiment 2). Results showed that 3‐month‐olds exhibit above‐chance discrimination of adult and infant faces, whereas 9‐month‐olds discriminate adult faces but not infant faces (Experiment 1). Moreover, adult faces, but not infant faces, induced significant increases in hemodynamic responses in the right temporal areas of 9‐month‐old infants. Overall, our data suggest that perceptual narrowing towards adult faces is a cross‐cultural phenomenon occurring between 3 and 9 months of age, and translates by 9 months of age into a right‐hemispheric specialization in the processing of adult faces.     

Tracking independence and merging of prosodic and phonemic processing across infancy

Recent evidence suggests division of labor in phonological analysis underlying speech recognition. Adults and children appear to decompose the speech stream into phoneme‐relevant information and into syllable stress. Here we investigate whether both speech processing streams develop from a common path in infancy, or whether there are two separate streams from early on. We presented stressed and unstressed syllables (spoken primes) followed by initially stressed early learned disyllabic German words (spoken targets). Stress overlap and phoneme overlap between the primes and the initial syllable of the targets varied orthogonally. We tested infants 3, 6 and 9 months after birth. Event‐related potentials (ERPs) revealed stress priming without phoneme priming in the 3‐month‐olds; phoneme priming without stress priming in the 6‐month‐olds; and phoneme priming, stress priming as well as an interaction of both in 9‐month‐olds. In general the present findings reveal that infants start with separate processing streams related to syllable stress and to phoneme‐relevant information; and that they need to learn to merge both aspects of speech processing. In particular the present results suggest (i) that phoneme‐free prosodic processing dominates in early infancy; (ii) that prosody‐free phoneme processing dominates in middle infancy; and (iii) that both types of processing are operating in parallel and can be merged in late infancy.     

Developmental changes in automatic rule‐learning mechanisms across early childhood

Infants’ ability to learn complex linguistic regularities from early on has been revealed by electrophysiological studies indicating that 3‐month‐olds, but not adults, can automatically detect non‐adjacent dependencies between syllables. While different ERP responses in adults and infants suggest that both linguistic rule learning and its link to basic auditory processing undergo developmental changes, systematic investigations of the developmental trajectories are scarce. In the present study, we assessed 2‐ and 4‐year‐olds’ ERP indicators of pitch discrimination and linguistic rule learning in a syllable‐based oddball design. To test for the relation between auditory discrimination and rule learning, ERP responses to pitch changes were used as predictor for potential linguistic rule‐learning effects. Results revealed that 2‐year‐olds, but not 4‐year‐olds, showed ERP markers of rule learning. Although, 2‐year‐olds’ rule learning was not dependent on differences in pitch perception, 4‐year‐old children demonstrated a dependency, such that those children who showed more pronounced responses to pitch changes still showed an effect of rule learning. These results narrow down the developmental decline of the ability for automatic linguistic rule learning to the age between 2 and 4 years, and, moreover, point towards a strong modification of this change by auditory processes. At an age when the ability of automatic linguistic rule learning phases out, rule learning can still be observed in children with enhanced auditory responses. The observed interrelations are plausible causes for age‐of‐acquisition effects and inter‐individual differences in language learning.     

“I don't know but I know who to ask”: 12‐month‐olds actively seek information from knowledgeable adults

Active social communication is an effective way for infants to learn about the world. Do pre‐verbal and pre‐pointing infants seek epistemic information from their social partners when motivated to obtain information they cannot discover independently? The present study investigated whether 12‐month‐olds (N = 30) selectively seek information from knowledgeable adults in situations of referential uncertainty. In a live experiment, infants were introduced to two unfamiliar adults, an Informant (reliably labeling objects) and a Non‐Informant (equally socially engaging, but ignorant about object labels). At test, infants were asked to make an impossible choice—locate a novel referent among two novel objects. When facing epistemic uncertainty—but not at other phases of the procedure—infants selectively referred to the Informant rather than the Non‐Informant. These results show that pre‐verbal infants use social referencing to actively and selectively seek information from social partners as part of their interrogative communicative toolkit. A video abstract of this article can be viewed at https://youtu.be/23dLPsa-fAY     

The role of sensorimotor experience in the development of mimicry in infancy

During social interactions we often have an automatic and unconscious tendency to copy or ‘mimic’ others’ actions. The dominant view on the neural basis of mimicry appeals to an automatic coupling between perception and action. It has been suggested that this coupling is formed through associative learning during correlated sensorimotor experience. Although studies with adult participants have provided support for this hypothesis, little is known about the role of sensorimotor experience in supporting the development of perceptual‐motor couplings, and consequently mimicry behaviour, in infancy. Here we investigated whether the extent to which an observed action elicits mimicry depends on the opportunity an infant has had to develop perceptual‐motor couplings for this action through correlated sensorimotor experience. We found that mothers’ tendency to imitate their 4‐month‐olds’ facial expressions during a parent‐child interaction session was related to infants’ facial mimicry as measured by electromyography. Maternal facial imitation was not related to infants’ mimicry of hand actions, and instead we found preliminary evidence that infants’ tendency to look at their own hands may be related to their tendency to mimic hand actions. These results are consistent with the idea that mimicry is supported by perceptual‐motor couplings that are formed through correlated sensorimotor experience obtained by observing one's own actions and imitative social partners.     

The Ontogeny of Long‐Term Retention During the Second Year of Life

Developmental changes in retention were assessed in two experiments with 18‐ and 24‐month‐old infants. In both experiments, infants were tested in a deferred imitation paradigm. In Experiment 1, independent groups of infants were tested either immediately or after delays of 1, 14, 28 or 56 days. There was no age‐related difference in the spontaneous production of target actions (baseline) or in immediate imitation. There were age‐related changes in retention after longer delays. Eighteen‐month‐olds exhibited retention for 14 days and 24‐month‐olds exhibited retention for at least 56 days. In Experiment 2, the maximum duration of retention by 24‐month‐olds was assessed. Independent groups of infants were tested after 3 or 6 months. Infants exhibited some evidence of retention after 3 months; however, forgetting was complete after 6 months.     

It's all good: Children's personality attributions after repeated success and failure in peer and computer interactions

The present study examined children's use of behavioural outcome information to make personality attributions in social and non‐social contexts. One hundred and twenty‐eight 3‐ to 6‐year‐olds were told about a story actor who engaged in primarily successful or primarily unsuccessful interactions with several different people (social context) or several different computers (non‐social context). Subsequently, children made behavioural predictions and trait attributions about the actor. Findings indicated that participants were more likely to use past information to make behavioural predictions and trait attributions when hearing about primarily successful than primarily unsuccessful interactions, although there were age‐related differences in trait attribution as a function of success and trait type. There was no support for differential use of information across contexts, as participants' predictions and attributions were similar regardless of hearing about interactions with computers or humans. Factors involved in the development of impression formation are discussed.