The development of infants' use of novel verbal information when reasoning about others' actions

Causal learning by infants and young children: From computational theories to language practices

Causal reasoning-the ability to reason about causal relations between events-is fundamental to understanding how the world works. This paper reviews two prominent theories on early causal learning and offers possibilities for theory bridging. Both theories grow out of computational modeling and have significant areas of overlap while differing in several respects. Explanation-Based Learning (EBL) focuses on young infants' learning about causal concepts of physical objects and events, whereas Bayesian models have been used to describe causal reasoning beyond infancy across various concept domains. Connecting the two models offers a more integrated approach to clarifying the developmental processes in causal reasoning from early infancy through later childhood. We further suggest that everyday language practices offer a promising space for theory bridging. We provide a review of selective work on caregiver-child conversations, in particular, on the use of scaffolding language including causal talk and pedagogical questions. Linking the research on language practices to the two cognitive theories, we point out directions for further research to integrate EBL and Bayesian models and clarify how causal learning unfolds in real life. This article is categorized under: Psychology > Learning Cognitive Biology > Cognitive Development.

Six-month-olds' ability to use linguistic cues when interpreting others' pointing actions

The present research investigated whether six-month-olds who rarely produce pointing actions can detect the object-directedness and communicative function of others' pointing actions when linguistic information is provided. In Experiment 1, infants were randomly assigned to either a novel-word or emotional-vocalization condition. They were first familiarized with an event in which an actor uttered either a novel label (novel-word condition) or exclamatory expression (emotional-vocalization condition) and then pointed to one of two objects. Next, the positions of the objects were switched. During test trials, each infant watched the new-referent event where the actor pointed to the object to which the actor had not pointed before or the old-referent event where the actor pointed to the old object in its new location. Infants in the novel-word condition looked reliably longer at the new-referent event than at the old-referent event, suggesting that they encoded the object-directedness of the actor's point. In contrast, infants in the emotional-vocalization condition showed roughly equal looking times to the two events. To further examine infants' understanding of the communicative aspect of an actor's point using a different communicative context, Experiment 2 used an identical procedure to the novel-word condition in Experiment 1, except there was only one object present during the familiarization trials. When the familiarization trials did not include a contrasting object, we found that the communicative intention of the actor's point could be ambiguous. The infants showed roughly equal looking times during the two test events. The current research suggests that six-month-olds understand the object-directedness and communicative intention of others' pointing when presented with a label, but not when presented with an emotional non-speech vocalization.

Fourteen- to Eighteen-Month-Old Infants Use Explicit Linguistic Information to Update an Agent's False Belief

The current research examined how infants exploit linguistic information to update an agent's false belief about an object's location. Fourteen- to eighteen-month-old infants first watched a series of events involving two agents, a ball, and two containers (a box and a cup). Agent1 repeatedly acted on the ball and then put it in the box in the presence of agent2. Then agent1 disappeared from the scene and agent2 switched the ball's location from the box to the cup. Upon agent1's return, agent2 told her, "The ball is in the cup!" Agent1 then reached for either the cup (cup event) or the box (box event). The infants looked reliably longer if shown the box event as opposed to the cup event. However, when agent2 simply said, "The ball and the cup!" - which does not explicitly mention the ball's new location - infants looked significantly longer if shown the cup event as opposed the box event. These findings thus provide new evidence for false-belief understanding in infancy and suggest that infants expect an agent's false belief to be updated only by explicit verbal information.

Bilingual and Monolingual First Language Acquisition Experience Differentially Shapes Children's Property Term Learning: Evidence from Behavioral and Neurophysiological Measures

Studies of novel noun learning show bilingual children rely less on the Mutual Exclusivity Constraint (MEC) for word learning than monolinguals. Shifting the focus to learning novel property terms (adjectives), the present study compared 3.5- and five-year-old bilingual and monolingual preschoolers' adherence to the MEC. We found no bilingual-monolingual differences on a behavioral forced-choice task for the 3.5-year-olds, but five-year-old monolinguals adhered more to the MEC than bilinguals did. Older bilinguals adhered less to the MEC than younger ones, while there was no difference in MEC adherence between the younger and older monolinguals. In the 5-year-olds, we additionally acquired neurophysiological data using functional near-infrared spectroscopy (fNIRS) to allow for a first explorative look at potential neuronal underpinnings. The data show that, compared to bilinguals, monolinguals reveal higher activation over three brain regions (right frontal, left temporo-parietal, and left prefrontal) that may be involved in exploiting the MEC, building on conflict detection, inhibition, solution of a disjunction, and working memory processes. Taken together, our behavioral and neurophysiological findings reveal different paths towards novel property term learning depending on children's language acquisition context.

Infants' understanding of the definite/indefinite article in a third-party communicative situation

The present study examines how infants use their emergent perspective-taking and language comprehension abilities to make sense of interactions between two human agents. In the study, one agent (Agent1) could see only one of two identical balls on an apparatus because of a screen obstructing her view while the infant and another agent (Agent2) could see both balls. 19-month-old English-learning monolingual infants seemed to expect Agent2 to grasp the ball visible to Agent1 when she said to Agent2 "Give me the ball" but not when she said "Give me a ball." 14-month-olds appeared to accept that Agent2 could grasp either ball when Agent1 said "Give me the ball." Therefore, by 19 months of age, English-learning infants seem to attend to the specific linguistic units used, e.g., the definite article, to identify the referent of others' speech. Possible reasons in connection with language acquisition processes and/or environmental factors for the two age groups' respective failures with the definite and the indefinite articles are discussed.

Infants' sensitivity to emotion in music and emotion-action understanding

Emerging evidence has indicated infants' early sensitivity to acoustic cues in music. Do they interpret these cues in emotional terms to represent others' affective states? The present study examined infants' development of emotional understanding of music with a violation-of-expectation paradigm. Twelve- and 20-month-olds were presented with emotionally concordant and discordant music-face displays on alternate trials. The 20-month-olds, but not the 12-month-olds, were surprised by emotional incongruence between musical and facial expressions, suggesting their sensitivity to musical emotion. In a separate non-music task, only the 20-month-olds were able to use an actress's affective facial displays to predict her subsequent action. Interestingly, for the 20-month-olds, such emotion-action understanding correlated with sensitivity to musical expressions measured in the first task. These two abilities however did not correlate with family income, parental estimation of language and communicative skills, and quality of parent-child interaction. The findings suggest that sensitivity to musical emotion and emotion-action understanding may be supported by a generalised common capacity to represent emotion from social cues, which lays a foundation for later social-communicative development.

Naming influences 9-month-olds' identification of discrete categories along a perceptual continuum

A growing body of evidence documents that naming guides 9-month-old infants as they organize their visual experiences into categories. In particular, this evidence reveals that naming highlights categories when these are visually distinct. Here we advance this work in by introducing an anticipatory looking design to assess how naming influences infants' categorization of objects that vary along a perceptual continuum. We introduced 9-month-old infants (n = 48) to continua of novel creature-like objects. During the learning phase, infants had an opportunity to observe that objects from one end of the perceptual continuum moved to the left and objects from the other end moved to the right. What varied was how the objects were named. Infants in theone-name condition heard the same novel noun applied to all objects along the continuum; those in the two-name condition heard one name for objects from one end of the continuum and a second name for objects at the other end. At test, all infants viewed new objects from the same continuum. At issue was whether infants would anticipate the side to which the test objects would move and whether their expectations varied as a function of naming condition. Infants in the one-name condition formed a single overarching category and therefore searched for new test objects at either location; those in the two-name condition discerned two categories and therefore correctly anticipated the likely location of the test objects, whether these were close to the poles or to the center of the continuum. This provides the first evidence that by 9 months, naming supports both the number of categories infants impose along a perceptual continuum and the clarity of the category boundaries.

Children's level of word knowledge predicts their exclusion of familiar objects as referents of novel words

When children are learning a novel object label, they tend to exclude as possible referents familiar objects for which they already have a name. In the current study, we wanted to know if children would behave in this same way regardless of how well they knew the name of potential referent objects, specifically, whether they could only comprehend it or they could both comprehend and produce it. Sixty-six monolingual German-speaking 2-, 3-, and 4-year-old children participated in two experimental sessions. In one session the familiar objects were chosen such that their labels were in the children's productive vocabularies, and in the other session the familiar objects were chosen such that their labels were only in the children's receptive vocabularies. Results indicated that children at all three ages were more likely to exclude a familiar object as the potential referent of the novel word if they could comprehend and produce its name rather than comprehend its name only. Indeed, level of word knowledge as operationalized in this way was a better predictor than was age. These results are discussed in the context of current theories of word learning by exclusion.

Do 12.5-month-old infants consider what objects others can see when interpreting their actions?

The present research examined whether 12.5-month-old infants take into account what objects an agent knows to be present in a scene when interpreting the agent's actions. In two experiments, the infants watched a female human agent repeatedly reach for and grasp object-A as opposed to object-B on an apparatus floor. Object-B was either (1) visible to the agent through a transparent screen; (2) hidden from the agent (but not the infants) by an opaque screen; or (3) placed by the agent herself behind the opaque screen, so that even though she could no longer see object-B, she knew of its presence there. The infants interpreted the agent's repeated actions toward object-A as revealing a preference for object-A over object-B only when she could see object-B (1) or was aware of its presence in the scene (3). These results indicate that, when watching an agent act on objects in a scene, 12.5-month-old infants keep track of the agent's representation of the physical setting in which these actions occur. If the agent's representation is incomplete, because the agent is ignorant about some aspect of the setting, infants use the agent's representation, rather than their own more complete representation, to interpret the agent's actions.

Can 9.5-month-old infants attribute to an agent a disposition to perform a particular action on objects?

The present research examined whether 9.5-month-old infants can attribute to an agent a disposition to perform a particular action on objects, and can then use this disposition to predict which of two new objects - one that can be used to perform the action and one that cannot - the agent is likely to reach for next. The infants first received familiarization trials in which they watched an agent slide either three (Experiments 1 and 3) or six (Experiment 2) different objects forward and backward on an apparatus floor. During test, the infants saw two new identical objects placed side by side: one stood inside a short frame that left little room for sliding, and the other stood inside a longer frame that left ample room for sliding. The infants who saw the agent slide six different objects attributed to her a disposition to slide objects: they expected her to select the "slidable" as opposed to the "unslidable" test object, and they looked reliably longer when she did not. In contrast, the infants who saw the agent slide only three different objects looked about equally when she selected either test object. These results add to recent evidence that infants in the first year of life can attribute dispositions to agents, and can use these dispositions to help predict agents' actions in new contexts.

Can infants attribute to an agent a disposition to perform a particular action?

The present research investigated whether 13.5-month-old infants would attribute to an actor a disposition to perform a recurring action, and would then use this information to predict which of two new objects-one that could be used to perform the action and one that could not-the actor would grasp next. During familiarization, the infants watched an actor slide various objects forward and backward on an apparatus floor. During test, the infants saw two new identical objects placed side by side: one stood inside a short frame that left little room for sliding; the other stood inside a longer frame that left ample room for sliding. The infants who saw the actor grasp the object inside the short frame looked reliably longer than those who saw the actor grasp the object inside the long frame. This and control results from a lifting condition provide evidence that by 13.5 months, infants can attribute to an actor a disposition to perform a particular action.