Think fast! The relationship between goal prediction speed and social competence in infants

What is in an action? Preschool children predict that agents take previous paths and not previous goals

Developmental science has experienced a vivid debate on whether young children prioritize goals over means in their prediction of others' actions. Influential developmental theories highlight the role of goal objects for action understanding. Yet, recent infant studies report evidence for the opposite. The empirical evidence is therefore inconclusive. The current study advanced this debate by assessing preschool children's verbal predictions of others' actions. In five experiments (N = 302), we investigated whether preschool children and adults predict agents to move towards their previous goal (that is, show goal-related predictions) or predict agents to move along the same movement path that they pursued before. While Experiments 1a, 1b and 1c presented young children and adults with animated agents, Experiments 2a and 2b presented participants with human grasping action. An integrative analysis across experiments revealed that children were more likely to predict the agent to move along the same movement path, Z = -4.574, p ≤ 0.0001 (r = 0.304). That is, preschool children were more likely to predict that agents would move along the same trajectory even though this action would lead to a new goal object. Thus, our findings suggest that young children's action prediction relies on the detection of spatial and movement information. Overall, we discuss our findings in terms of theoretical frameworks that conceive of action understanding as an umbrella term that comprises different forms and facets in which humans understand others' actions. RESEARCH HIGHLIGHTS: We investigated whether preschool children predict agents to move towards their previous goal or to move along the same movement path that they pursued before. Unlike adults, preschool children predicted that agents would move along the same trajectory even though this action would lead to a new goal. Adults' goal-based predictions were affected from contextual details, whereas children systematically made path-based predictions. Young children's action prediction relies on the detection of spatial and movement information.

The Origins of Theory of Mind in Infant Social Cognition: Investigating Longitudinal Pathways from Intention Understanding and Joint Attention to Preschool Theory of Mind

A growing body of literature has established longitudinal associations between key social cognitive capacities emerging in infancy and children's subsequent theory of mind. However, existing work is limited by modest sample sizes, narrow infant measures, and theory of mind assessments with restricted variability and generalizability. The current study aimed to extend this literature by (a) recruiting a large sample of participants (n = 116; 53 boys; 63 girls; all U.S. residents; 88 White, 8 Hispanic or Latino, 2 Black or African American, 14 two or more races/ethnicities, 4 unknown; median family income: $74-122,000), (b) examining multiple measures of infant social cognition (intentional action understanding, responding to joint attention, initiating joint attention) at Time 1 (8-12 months), and (c) using an ecologically valid theory of mind assessment designed to capture individual differences in preschoolers' mental state understanding (the Children's Social Understanding Scale; Tahiroglu et al., 2014) at Time 2 (37-45 months). Measured variable path analysis revealed a significant longitudinal association between infants' initiating joint attention and later theory of mind: infants who engaged in more attempts to initiate joint attention with experimenters through gaze alternation or gestures went on to show better parent-reported mental state understanding as preschoolers. Notably, the paths from infants' responding to joint attention and intentional action understanding to later theory of mind did not emerge as significant. These findings bolster and clarify existing claims about how mental state reasoning is rooted in foundational social-cognitive capacities emerging in infancy.

Three-year-olds' Perspective-taking in Social Interactions: Relations with Socio-cognitive Skills

Understanding others’ perspectives and integrating this knowledge in social interactions is challenging for young children; even adults struggle with this skill. While young children show the capacity to understand what others can and cannot see under supportive laboratory conditions, more research is necessary to understand how children implement their perspective-taking (PT) skill during interactions and which socio-cognitive skills support their ability to do so. This preregistered study examined children’s Level 1 visual PT in a real-time social interaction and tested whether social-cognitive skills (focusing on inhibition of imitation) predicted PT. Thirty-six 3-year-old children (mean age: 37.3 months) participated in a PT task and responded implicitly (via eye gaze) and explicitly (via toy choice) to situations where their communicative partner could see some objects but not others. Three-year-olds demonstrated sensitivity to another’s perspective via implicit responses, but did not consistently take their partner’s perspective into account in their actions when considering objects their partner could not see. Contrary to adult findings, children who struggled to inhibit imitating (those more affected by another’s actions) demonstrated better PT, again when considering objects outside their partner’s sight. Thus, 3-year-olds’ sensitivity to others’ perspectives was robust, while acting on PT knowledge may still be developing; further, children more affected by another’s actions demonstrated improved PT skills.

Stopping at nothing: Two-year-olds differentiate between interrupted and abandoned goals

Previous research has established that goal tracking emerges early in the first year of life and rapidly becomes increasingly sophisticated. However, it has not yet been shown whether young children continue to update their representations of others' goals over time. The current study investigated this by probing young children's (24- to 30-month-olds; N = 24) ability to differentiate between goal-directed actions that have been halted because the goal was interrupted and those that have been halted because the goal was abandoned. To test whether children are sensitive to this distinction, we manipulated the experimenter's reason for not completing a goal-directed action; his initial goal was either interrupted by an obstacle or abandoned in favor of an alternative. We measured whether children's helping behavior was sensitive to the experimenter's reason for not completing his goal-directed action by recording whether children completed the experimenter's initial goal or the alternative goal. The results showed that children helped to complete the experimenter's initial goal significantly more often after this goal had been interrupted than after it had been abandoned. These results support the hypothesis that children continue to update their representations of others' goals over time by 2 years of age and specifically that they differentiate between abandoned and interrupted goals.

Action prediction during real-time parent-infant interactions

Social interactions provide a crucial context for early learning and cognitive development during infancy. Action prediction-the ability to anticipate an observed action-facilitates successful, coordinated interaction and is an important social-cognitive skill in early development. However, current knowledge about infant action prediction comes largely from screen-based laboratory tasks. We know little about what infants' action prediction skills look like during real-time, free-flowing interactions with a social partner. In the current study, we used head-mounted eyetracking to quantify 9-month-old infants' visual anticipations of their parents' actions during free-flowing parent-child play. Our findings reveal that infants do anticipate their parents' actions during dynamic interactions at rates significantly higher than would be expected by chance. In addition, the frequency with which they do so is associated with child-led joint attention and hand-eye coordination. These findings are the first to reveal infants' action prediction behaviors in a more naturalistic context than prior screen-based studies, and they support the idea that action prediction is inherently linked to motor development and plays an important role in infants' social-cognitive development. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=9HrmcicfiqE.

Do Children and Adults with Autism Spectrum Condition Anticipate Others' Actions as Goal-Directed? A Predictive Coding Perspective

An action's end state can be anticipated by considering the agent's goal, or simply by projecting the movement trajectory. Theories suggest that individuals with autism spectrum condition (ASC) have difficulties anticipating other's goal-directed actions, caused by an impairment using prior information. We examined whether children, adolescents and adults with and without ASC visually anticipate another's action based on its goal or movement trajectory by presenting participants an agent repeatedly taking different paths to reach the same of two targets. The ASC group anticipated the goal and not just the movement pattern, but needed more time to perform goal-directed anticipations. Results are in line with predictive coding accounts, claiming that the use of prior information is impaired in ASC.

Intentional action processing across the transition to crawling: Does the experience of self-locomotion impact infants' understanding of intentional actions?

Motor developmental milestones in infancy, such as the transition to self-locomotion, have cascading implications for infants' social and cognitive development. The current studies aimed to add to this literature by exploring whether and how crawling experience impacts a key social-cognitive milestone achieved in infancy: the development of intentional action understanding. Study 1 used a cross-sectional, age-held-constant design to examine whether locomotor (n = 36) and prelocomotor (n = 36) infants differ in their ability to process a failed intentional reaching action. Study 2 (n = 124) further probed this question by assessing how variability in locomotor infants' experience maps onto variability in their failed intentional action understanding. Both studies also assessed infants' tendency to engage in triadic interactions to shed light on whether self-locomotion impacts intentional action understanding directly or indirectly via changes in infants' interactions with social partners. Altogether, results showed no evidence for the role of self-locomotion in the development of intentional action understanding. Locomotor and prelocomotor infants did not differ in their failed action understanding or levels of triadic engagement (Study 1) and individual differences in days of crawling experience, propensity to crawl during play, and maximum crawling speed failed to predict infants' intentional action understanding or triadic engagement (Study 2). Explanations for these null findings and alternative influences on the development of intentional action understanding are considered.

Let's get it together: Infants generate visual predictions based on collaborative goals

Infants engage in social interactions that include multiple partners from very early in development. A growing body of research shows that infants visually predict the outcomes of an individual's intentional actions, such as a person reaching towards an object (e.g., Krogh-Jespersen & Woodward, 2014), and even show sophistication in their predictions regarding failed actions (e.g., Brandone, Horwitz, Aslin, & Wellman, 2014). Less is known about infants' understanding of actions involving more than one individual (e.g., collaborative actions), which require representing each partners' actions in light of the shared goal. Using eye-tracking, Study 1 examined whether 14-month-old infants visually predict the actions of an individual based on her previously shared goal. Infants viewed videos of two women engaged in either a collaborative or noncollaborative interaction. At test, only one woman was present and infants' visual predictions regarding her future actions were measured. Fourteen-month-olds anticipated an individual's future actions based on her past collaborative behavior. Study 2 revealed that 11-month-old infants only visually predict higher-order shared goals after engaging in a collaborative intervention. Together, our results indicate that by the second year after birth, infants perceive others' collaborative actions as structured by shared goals and that active engagement in collaboration strengthens this understanding in young infants.

Posterior Fossa Arachnoid Cyst in a Pediatric Population is Associated with Social Perception and Rest Cerebral Blood Flow Abnormalities

Posterior fossa arachnoid cysts (PFAC) may produce not only neurological symptoms but also other symptoms still poorly understood such as behavioral and learning deficits, awkwardness, and difficulties in social interaction. These subtle social impairments have not been formally described and their underlying brain mechanisms remain unknown. In the present case-control study, we aimed to empirically characterize social impairments in a pediatric population with PFAC using eye tracking. In addition, we investigated putative functional cortical abnormalities in these children using arterial spin labeling magnetic resonance imaging. Overall, 15 patients with PFAC (3f, age = 9.4 ± 4 years) and 43 typically developing volunteer children (16f, age = 9.3 ± 3.6 years) were enrolled in this study. Eye tracking was used to record gaze patterns during visualization of social interaction scenes. Viewing times to faces of characters and non-social background were analyzed. A voxel-wise whole-brain analysis was performed to investigate rest cerebral blood flow (CBF) abnormalities. Significantly reduced viewing time to faces was observed in patients compared with controls (p < 0.01). A ROC curve analysis revealed that 30% of PFAC patients presented viewing time to the face lower than the cutoff, while none of the controls did. The whole-brain analysis revealed a significant decrease in rest CBF in PFAC patients compared with controls bilaterally in the superior temporal gyrus and the temporoparietal junction (TPJ) (p < 0.05 FWE). These results suggest that early life PFAC may have an impact on functional activity of the temporal lobe, which could be associated with social perception deficits.

Triadic interactions support infants' emerging understanding of intentional actions

Infants' understanding of the intentional nature of human action develops gradually across the first year of life. A key question is what mechanisms drive changes in this foundational social-cognitive ability. The current studies explored the hypothesis that triadic interactions in which infants coordinate attention between a social partner and an object of mutual interest promote infants' developing understanding of others as intentional agents. Infants' spontaneous tendency to participate in triadic engagement was assessed in a semi-structured play session with a researcher. Intentional action understanding was assessed by evaluating infants' ability to visually predict the goal of an intentional reaching action. Study 1 (N = 88) revealed that 8- to 9-month-olds who displayed more bouts of triadic engagement showed better concurrent reasoning about the goal of an intentional reaching action. Study 2 (N = 114) confirmed these findings using a longitudinal design and demonstrated that infants who displayed more bouts of triadic engagement at 6-7 months were better at prospectively reasoning about the goal of an intentional reaching action 3 months later. Cross-lagged path analyses revealed that intentional action understanding at 6-7 months did not predict later triadic engagement, suggesting that early triadic engagement supports later intentional action processing and not the other way around. Finally, evidence from both studies revealed the unique contribution of triadic over dyadic forms of engagement. These results highlight the importance of social interaction as a developmental mechanism and suggest that infants enrich their understanding of intentionality through triadic interactions with social partners.

Six-Month-Old Infants Predict Agents' Goal-Directed Actions on Occluded Objects

Infants can infer agents' goals after observing agents' goal-directed actions on objects and can subsequently make predictions about how agents will act on objects in the future. We investigated the representations supporting these predictions. We familiarized 6-month-old infants to an agent who preferentially reached for one of two featurally distinct objects following a cue. At test, the objects were sequentially occluded from the infant in the agent's presence. We asked whether infants could generate action predictions without visual access to the relevant objects by measuring whether infants shifted their gaze to the location of the agent's hidden goal object following the cue. We also examined what infants represented about the hidden objects by removing one of the occluders to reveal either the original hidden object or the unexpected other object and measuring infants' looking time. We found that, even without visual access to the objects, infants made predictive gazes to the location of the agent's occluded goal object, but failed to represent the features of either hidden object. These results suggest that infants make goal-based action predictions when the relevant objects in the scene are occluded, but doing so may come at the expense of maintaining representations of the objects.

Oxytocin promotes action prediction

The neuropeptide oxytocin (OT) has been suggested to facilitate social cognition and behavior. As predicting others' behavior is at the core of human social-cognitive abilities and is indispensable for successful social interaction, we hypothesized that OT would increase action prediction. To test this hypothesis, 61 male and female healthy participants self-administered OT or placebo intranasally and their anticipatory eye-movements were recorded using eye-tracking techniques. We found that the ability to predict others' future actions was enhanced following OT treatment. This effect was mediated by the time to the first anticipatory eye-movement suggesting that improved action prediction might operate by increased attention to social cues. These findings provide direct evidence for the role of OT in promoting perception and processing of social cues.

Goal prediction in 2-year-old children with and without autism spectrum disorder: An eye-tracking study

This study examined the predictive reasoning abilities of typically developing (TD) infants and 2-year-old children with autism spectrum disorder (ASD) in an eye-tracking paradigm. Participants watched a video of a goal-directed action in which a human actor reached for and grasped one of two objects. At test, the objects switched locations. Across these events, we measured: visual anticipation of the action outcome with kinematic cues (i.e., a completed reaching behavior); goal prediction of the action outcome without kinematic cues (i.e., an incomplete reach); and latencies to generate predictions across these two tasks. Results revealed similarities in action anticipation across groups when trajectory information regarding the intended goal was present; however, when predicting the goal without kinematic cues, developmental and diagnostic differences became evident. Younger TD children generated goal-based visual predictions, whereas older TD children were not systematic in their visual predictions. In contrast to both TD groups, children with ASD generated location-based predictions, suggesting that their visual predictions may reflect visuomotor perseveration. Together, these results suggest differences in early predictive reasoning abilities. Autism Res 2018, 11: 870-882. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

The current study examines the ability to generate visual predictions regarding other people's goal-directed actions, specifically reaching and grasping an object, in infants and children with and without autism spectrum disorder. Results showed no differences in abilities when movement information about a person's goal was evident; however, differences were evident across age and clinical diagnoses when relying on previous knowledge to generate a visual prediction.

Reaching the goal: Active experience facilitates 8-month-old infants' prospective analysis of goal-based actions

From early in development, infants view others' actions as structured by intentions, and this action knowledge may be supported by shared action production/perception systems. Because the motor system is inherently prospective, infants' understanding of goal-directed actions should support predictions of others' future actions, yet little is known about the nature and developmental origins of this ability, specifically whether young infants use the goal-directed nature of an action to rapidly predict future social behaviors and whether their action experience influences this ability. Across three conditions, we varied the level of action experience infants engaged in to determine whether motor priming influenced infants' ability to generate rapid social predictions. Results revealed that young infants accurately generated goal-based visual predictions when they had previously been reaching for objects; however, infants who passively observed a demonstration were less successful. Further analyses showed that engaging the cognitively based prediction system to generate goal-based predictions following motor engagement resulted in slower latencies to predict, suggesting that these smart predictions take more time to deploy. Thus, 8-month-old infants may have motor representations of goal-directed actions, yet this is not sufficient for them to predict others' actions; rather, their own action experience supports the ability to rapidly implement knowledge to predict future behavior.

Action Prediction Allows Hypothesis Testing via Internal Forward Models at 6 Months of Age

We propose that action prediction provides a cornerstone in a learning process known as internal forward models. According to this suggestion infants' predictions (looking to the mouth of someone moving a spoon upward) will moments later be validated or proven false (spoon was in fact directed toward a bowl), information that is directly perceived as the distance between the predicted and actual goal. Using an individual difference approach we demonstrate that action prediction correlates with the tendency to react with surprise when social interactions are not acted out as expected (action evaluation). This association is demonstrated across tasks and in a large sample (n = 118) at 6 months of age. These results provide the first indication that infants might rely on internal forward models to structure their social world. Additional analysis, consistent with prior work and assumptions from embodied cognition, demonstrates that the latency of infants' action predictions correlate with the infant's own manual proficiency.

When veps cry: Two-year-olds efficiently learn novel words from linguistic contexts alone

We assessed 24-month-old infants' lexical processing efficiency for both novel and familiar words. Prior work documented that 19-month-olds successfully identify referents of familiar words (e.g., The dog is so little) as well as novel words whose meanings were informed only by the surrounding sentence (e.g., The vep is crying), but that the speed with which they identify the referents of novel words lagged far behind that for familiar words. Here we take a developmental approach, extending this work to 24-month-olds. By comparing the performance of 19- and 24-month-olds directly, we document that during this period of rapid vocabulary growth, infants make significant processing gains for both familiar and novel words. We also offer the first evidence to date that, at both 19- and 24-months, the number of verbs infants know predicts their ability to use known verbs to learn novel nouns. These results reveal that 24-month-olds can efficiently learn novel words just by listening to the conversations around them.

Action perception in infancy: the plasticity of 7-month-olds' attention to grasping actions

The present study investigates the plasticity of 7-month-old infants' orienting of attention during their perception of grasping actions. Previous research has shown that when infants observe a grasping hand, they shift their attention in line with the grasping direction, which is indicated by a reliable priming effect in this direction. The mechanisms behind this priming effect are largely unknown, and it is unclear how malleable this priming effect is with respect to a brief exposure to novel action-target contingencies. In a spatial-cueing paradigm, we presented a series of training trials prior to a series of test trials. These training sequences significantly modulated infants' attention. This suggests that action perception, when assessed through shifts of attention, is not solely based on the infants' grasping experience but quickly adapts to context-specific observed regularities.

Preschoolers, adolescents, and adults visually anticipate an agent's efficient action; but only after having observed it frequently

The present study examined the contribution of efficiency reasoning and statistical learning on visual action anticipation in preschool children, adolescents, and adults. To this end, Experiment 1 assessed proactive eye movements of 5-year-old children, 15-year-old adolescents, and adults, who observed an agent stating the intent to reach a goal as quickly as possible. Subsequently the agent could four times either take a short, hence efficient, or long, hence inefficient, path to get to the goal. The results showed that in the first trial participants in none of the age groups predicted above chance level that the agent would produce the efficient action. Instead, we observed an age-dependent increase in action predictions in the subsequent repeated presentation of the same action. Experiment 2 ruled out that participants’ nonconsideration of the efficient path was due to a lack of understanding of the agent's action goal. Moreover, it demonstrated that 5-year-old children do predict that the agent will act efficiently when verbally reasoning about his future action. Overall, the study supports the view that rapid learning from frequency information guides visual action anticipations.

Exposure to multiple languages enhances communication skills in infancy

Early exposure to multiple languages can enhance children's communication skills, even when children are effectively monolingual (Fan, Liberman, Keysar & Kinzler, ). Here we report evidence that the social benefits of multilingual exposure emerge in infancy. Sixteen-month-old infants participated in a communication task that required taking a speaker's perspective to understand her intended meaning. Infants were presented with two identical toys, such as two cars. One toy was mutually visible to both the infant and the speaker, but the other was visible only to the infant and was blocked from the speaker's view by an opaque barrier. The speaker requested the mutually visible toy and we evaluated whether infants understood the speaker's request. Whereas monolingual infants were at chance in choosing between the two toys, infants with multilingual exposure reliably chose the toy the speaker requested. Successful performance was not related to the degree of exposure to other languages, suggesting that even minimal multilingual exposure may enhance communication skills.

Humans but Not Chimpanzees Vary Face-Scanning Patterns Depending on Contexts during Action Observation

Human and nonhuman primates comprehend the actions of other individuals by detecting social cues, including others’ goal-directed motor actions and faces. However, little is known about how this information is integrated with action understanding. Here, we present the ontogenetic and evolutionary foundations of this capacity by comparing face-scanning patterns of chimpanzees and humans as they viewed goal-directed human actions within contexts that differ in whether or not the predicted goal is achieved. Human adults and children attend to the actor’s face during action sequences, and this tendency is particularly pronounced in adults when observing that the predicted goal is not achieved. Chimpanzees rarely attend to the actor’s face during the goal-directed action, regardless of whether the predicted action goal is achieved or not. These results suggest that in humans, but not chimpanzees, attention to actor’s faces conveying referential information toward the target object indicates the process of observers making inferences about the intentionality of an action. Furthermore, this remarkable predisposition to observe others’ actions by integrating the prediction of action goals and the actor’s intention is developmentally acquired.