Does causal action facilitate causal perception in infants younger than 6 months of age?

The primacy of experience in language processing: Semantic priming is driven primarily by experiential similarity

The organization of semantic memory, including memory for word meanings, has long been a central question in cognitive science. Although there is general agreement that word meaning representations must make contact with sensory-motor and affective experiences in a non-arbitrary fashion, the nature of this relationship remains controversial. One prominent view proposes that word meanings are represented directly in terms of their experiential content (i.e., sensory-motor and affective representations). Opponents of this view argue that the representation of word meanings reflects primarily taxonomic structure, that is, their relationships to natural categories. In addition, the recent success of language models based on word co-occurrence (i.e., distributional) information in emulating human linguistic behavior has led to proposals that this kind of information may play an important role in the representation of lexical concepts. We used a semantic priming paradigm designed for representational similarity analysis (RSA) to quantitatively assess how well each of these theories explains the representational similarity pattern for a large set of words. Crucially, we used partial correlation RSA to account for intercorrelations between model predictions, which allowed us to assess, for the first time, the unique effect of each model. Semantic priming was driven primarily by experiential similarity between prime and target, with no evidence of an independent effect of distributional or taxonomic similarity. Furthermore, only the experiential models accounted for unique variance in priming after partialling out explicit similarity ratings. These results support experiential accounts of semantic representation and indicate that, despite their good performance at some linguistic tasks, the distributional models evaluated here do not encode the same kind of information used by the human semantic system.

Exploring the influence of self-identification on perceptual judgments of physical and social causality

People tend to overestimate the causal contribution of the self to the observed outcome in various situations, a cognitive bias known as the 'illusion of control.' This study delves into whether this cognitive bias impacts causality judgments in animations depicting physical and social causal interactions. In two experiments, participants were instructed to associate themselves and a hypothetical stranger identity with two geometrical shapes (a circle and a square). Subsequently, they viewed animations portraying these shapes assuming the roles of agent and patient in causal interactions. Within one block, the shape related to the self served as the agent, while the shape associated with the stranger played the role of the patient. Conversely, in the other block, the identity-role association was reversed. We posited that the perception of the self as a causal agent might influence explicit judgments of physical and social causality. Experiment 1 demonstrated that physical causality ratings were solely shaped by kinematic cues. In Experiment 2, emphasising social causality, the dominance of kinematic parameters was confirmed. Therefore, contrary to the hypothesis anticipating diminished causality ratings with specific identity-role associations, results indicated negligible impact of our manipulation. The study contributes to understanding the interplay between kinematic and non-kinematic cues in human causal reasoning. It suggests that explicit judgments of causality in simple animations primarily rely on low-level kinematic cues, with the cognitive bias of overestimating the self's contribution playing a negligible role.

Infants rationally infer the goals of other people's reaches in the absence of first-person experience with reaching actions

Does knowledge of other people's minds grow from concrete experience to abstract concepts? Cognitive scientists have hypothesized that infants' first-person experience, acting on their own goals, leads them to understand others' actions and goals. Indeed, classic developmental research suggests that before infants reach for objects, they do not see others' reaches as goal-directed. In five experiments (N = 117), we test an alternative hypothesis: Young infants view reaching as undertaken for a purpose but are open-minded about the specific goals that reaching actions are aimed to achieve. We first show that 3-month-old infants, who cannot reach for objects, lack the expectation that observed acts of reaching will be directed to objects rather than to places. Infants at the same age learned rapidly, however, that a specific agent's reaching action was directed either to an object or to a place, after seeing the agent reach for the same object regardless of where it was, or to the same place regardless of what was there. In a further experiment, 3-month-old infants did not demonstrate such inferences when they observed an actor engaging in passive movements. Thus, before infants have learned to reach and manipulate objects themselves, they infer that reaching actions are goal-directed, and they are open to learning that the goal of an action is either an object or a place. RESEARCH HIGHLIGHTS: In the present experiments, 3-month-old prereaching infants learned to attribute either object goals or place goals to other people's reaching actions. Prereaching infants view agents' actions as goal-directed, but do not expect these acts to be directed to specific objects, rather than to specific places. Prereaching infants are open-minded about the specific goal states that reaching actions aim to achieve.

The Primacy of Experience in Language Processing: Semantic Priming Is Driven Primarily by Experiential Similarity

The organization of semantic memory, including memory for word meanings, has long been a central question in cognitive science. Although there is general agreement that word meaning representations must make contact with sensory-motor and affective experiences in a non-arbitrary fashion, the nature of this relationship remains controversial. One prominent view proposes that word meanings are represented directly in terms of their experiential content (i.e., sensory-motor and affective representations). Opponents of this view argue that the representation of word meanings reflects primarily taxonomic structure, that is, their relationships to natural categories. In addition, the recent success of language models based on word co-occurrence (i.e., distributional) information in emulating human linguistic behavior has led to proposals that this kind of information may play an important role in the representation of lexical concepts. We used a semantic priming paradigm designed for representational similarity analysis (RSA) to quantitatively assess how well each of these theories explains the representational similarity pattern for a large set of words. Crucially, we used partial correlation RSA to account for intercorrelations between model predictions, which allowed us to assess, for the first time, the unique effect of each model. Semantic priming was driven primarily by experiential similarity between prime and target, with no evidence of an independent effect of distributional or taxonomic similarity. Furthermore, only the experiential models accounted for unique variance in priming after partialling out explicit similarity ratings. These results support experiential accounts of semantic representation and indicate that, despite their good performance at some linguistic tasks, the distributional models evaluated here do not encode the same kind of information used by the human semantic system.

The possibility of an impetus heuristic

Evidence consistent with a belief in impetus is drawn from studies of naïve physics, perception of causality, perception of force, and representational momentum, and the possibility of an impetus heuristic is discussed. An impetus heuristic suggests the motion path of an object that was previously constrained or influenced by an external source (e.g., object, force) appears to exhibit the same constraint or influence even after that constraint or influence is removed. Impetus is not a valid physical principle, but use of an impetus heuristic can in some circumstances provide approximately correct predictions regarding future object motion, and such predictions require less cognitive effort and resources than would predictions based upon objective physical principles. The relationship of an impetus heuristic to naïve impetus theory and to objective physical principles is discussed, and use of an impetus heuristic significantly challenges claims that causality or force can be visually perceived. Alternatives to an impetus heuristic are considered, and potential boundary conditions and falsification of the impetus notion are discussed. Overall, use of an impetus heuristic offers a parsimonious explanation for findings across a wide range of perceptual domains and could potentially be extended to more metaphorical types of motion.

Effect of Contingency Paradigm-Based Interventions on Developmental Outcomes in Young Infants: A Systematic Review

PURPOSE

The purpose of this systematic review was to identify controlled trials evaluating the efficacy of contingency paradigm-based interventions to improve feeding, motor, or cognitive outcomes during the first year of life.

SUMMARY OF KEY POINTS

Seventeen studies, including 10 randomized controlled trials, incorporating contingency paradigm-based interventions were identified. Three of 3 trials reported improvements in nutritive sucking using pacifier-activated lullaby in preterm infants before term age. Seven of 12 trials reported improvements in reaching, manual exploration, and kicking behaviors in term and preterm infants; and 6 of 10 trials reported gains in early cognition using sticky mittens and contingent toys.

CONCLUSION AND RECOMMENDATIONS FOR CLINICAL PRACTICE

Contingency paradigm-based interventions can improve feeding outcomes in the neonatal intensive care unit in very preterm infants, and increase reaching, and perceptual-cognitive behaviors in term infants. Future research is needed to establish contingency paradigms as an effective early intervention strategy.

WHAT THIS ADDS TO THE EVIDENCE

This review synthesizes a body of literature on contingency paradigm-based interventions and highlights its potential paradigm-based interventions to improve developmental outcomes in infants.

"May I Grab Your Attention?": An Investigation Into Infants' Visual Preferences for Handled Objects Using Lookit as an Online Platform for Data Collection

We examined the relation between 4- to 12-month-old infants' (N = 107) motor development and visual preference for handled or non-handled objects, using Lookit (lookit.mit.edu) as an online tool for data collection. Infants viewed eight pairs of objects, and their looking was recorded using their own webcam. Each pair contained one item with an easily graspable “handle-like” region and one without. Infants' duration of looking at each item was coded from the recordings, allowing us to evaluate their preference for the handled item. In addition, parents reported on their infants' motor behavior in the previous week. Overall, infants looked longer to handled items than non-handled items. Additionally, by examining the duration of infants' individual looks, we show that differences in infants' interest in the handled items varied both by infants' motor level and across the course of the 8-s trials. These findings confirm infant visual preferences can be successfully measured using Lookit and that motor development is related to infants' visual preferences for items with a graspable, handle-like region. The relative roles of age and motor development are discussed.

Children do not distinguish efficient from inefficient actions during observation

Observation is a powerful way to learn efficient actions from others. However, the role of observers' motor skill in assessing efficiency of others is unknown. Preschoolers are notoriously poor at performing multi-step actions like grasping the handle of a tool. Preschoolers (N = 22) and adults (N = 22) watched video-recorded actors perform efficient and inefficient tool use. Eye tracking showed that preschoolers and adults looked equally long at the videos, but adults looked longer than children at how actors grasped the tool. Deep learning analyses of participants' eye gaze distinguished efficient from inefficient grasps for adults, but not for children. Moreover, only adults showed differential action-related pupil dilation and neural activity (suppressed oscillation power in the mu frequency) while observing efficient vs. inefficient grasps. Thus, children observe multi-step actions without "seeing" whether the initial step is efficient. Findings suggest that observer's own motor efficiency determines whether they can perceive action efficiency in others.

When correlation equals causation: A behavioral and computational account of second-order correlation learning in children

We examined 2- and 3-year-old children's ability to use second-order correlation learning-in which a learned correlation between two pairs of features (e.g., A and B, A and C) is generalized to the noncontiguous features (i.e., B and C)-to make causal inferences. Previous findings showed that 20- and 26-month-old children can use second-order correlation learning to learn about static and dynamic features in category and noncategory contexts. The current behavioral study and computational model extend these findings to show that 2- and 3-year-olds can detect the second-order correlation between an object's surface feature and its capacity to activate a novel machine, but only if the children had encoded the first-order correlations on which the second-order correlation was based. These results have implications for children's developing information-processing capacities on their ability to use second-order correlations to infer causal relations in the world.

The sticky mittens paradigm: A critical appraisal of current results and explanations

Almost two decades ago, the sticky mittens paradigm was demonstrated as a way to train reaching and grasping behaviors in pre‐reaching infants, and consequently improve visual attentional abilities. In that first study, Needham and colleagues fitted 3‐month‐old infants with Velcro loop‐covered mittens and allowed them to interact with Velcro hook‐covered toys over the course of 2 weeks. In this review, we scrutinize the 17 studies that have followed those first sticky mittens results in regards to the motor, social perception, and visual attentional domains. Furthermore, we discuss the proposed mechanisms of the sticky mittens training. Current evidence strongly suggests that sticky mittens training facilitates social perception, which is consistent with prior correlational work showing links between action production and action perception. However, studies targeting motor and visual attentional abilities have too diverse results to warrant firm conclusions. We conclude that future research should focus on uncovering if there is a connection between sticky mittens training and motor behavior.

When it all falls down: the relationship between intuitive physics and spatial cognition

Our intuitive understanding of physical dynamics is crucial in daily life. When we fill a coffee cup, stack items in a refrigerator, or navigate around a slippery patch of ice, we draw on our intuitions about how physical interactions will unfold. What mental machinery underlies our ability to form such inferences? Numerous aspects of cognition must contribute - for example, spatial thinking, temporal prediction, and working memory, to name a few. Is intuitive physics merely the sum of its parts - a collection of these and other related abilities that we apply to physical scenarios as we would to other tasks? Or does physical reasoning rest on something extra - a devoted set of mental resources that takes information from other cognitive systems as inputs? Here, we take a key step in addressing this question by relating individual differences on a physical prediction task to performance on spatial tasks, which may be most likely to account for intuitive physics abilities given the fundamentally spatial nature of physical interactions. To what degree can physical prediction performance be disentangled from spatial thinking? We tested 100 online participants in an “Unstable Towers” task and measures of spatial cognition and working memory. We found a positive relationship between intuitive physics and spatial skills, but there were substantial, reliable individual differences in physical prediction ability that could not be accounted for by spatial measures or working memory. Our findings point toward the separability of intuitive physics from spatial cognition.

Play enhances visual form perception in infancy-an active training study

Motor experiences and active exploration during early childhood may affect individual differences in a wide range of perceptual and cognitive abilities. In the current study, we suggest that active exploration of objects facilitates the ability to process object forms and magnitudes, which in turn impacts the development of numerosity perception. We tested our hypothesis by conducting a preregistered active exploration intervention with 59 8-month-old infants. The minimal intervention consisted of actively playing with and exploring blocks once a day for 8 weeks. In order to control for possible training effects on attention, we used book reading as a control condition. Pre- and post-test assessments using eye-tracking showed that block play improved visual form perception, where infants became better at detecting a deviant shape. Furthermore, using three control tasks, we showed that the intervention specifically improved infants' ability to process visual forms and the effect could not be explained by a domain general improvement in attention or visual perception. We found that the intervention did not improve numerosity perception and suggest that because of the sequential nature of our hypothesis, a longer time frame might be needed to see improvements in this ability. Our findings indicate that if infants are given more opportunities for play and exploration, it will have positive effects on their visual form perception, which in turn could help their understanding of geometrical concepts.

Better all by myself: Gaining personal experience, not watching others, improves 3-year-olds' performance in a causal trap task

Children often learn from others' demonstrations, but in the causal domain evidence acquired from observing others may be more ambiguous than evidence generated for oneself. Prior work involving tool-using tasks suggests that observational learning might not provide sufficient information about the causal relations involved, but it remains unclear whether these limitations can be mitigated by providing demonstrations using familiar manual actions rather than unfamiliar tools. We provided 2.5- to 3.5-year-old children (N = 67) with the opportunity to acquire experience with a causal trap task by hand or by tool actively or from observing others. Initially, children either generated their own experience or watched a yoked demonstration; all children then attempted the trap task with the tool. Children who generated their own experience outperformed those who watched the demonstration. Hand or tool use had no effect on performance with a tool. The implications of these findings for scaffolding self-guided learning and for demonstrations involving errors are discussed.

Self-generated variability in object images predicts vocabulary growth

Object names are a major component of early vocabularies and learning object names depends on being able to visually recognize objects in the world. However, the fundamental visual challenge of the moment-to-moment variations in object appearances that learners must resolve has received little attention in word learning research. Here we provide the first evidence that image-level object variability matters and may be the link that connects infant object manipulation to vocabulary development. Using head-mounted eye tracking, the present study objectively measured individual differences in the moment-to-moment variability of visual instances of the same object, from infants' first-person views. Infants who generated more variable visual object images through manual object manipulation at 15 months of age experienced greater vocabulary growth over the next six months. Elucidating infants' everyday visual experiences with objects may constitute a crucial missing link in our understanding of the developmental trajectory of object name learning.

Any way the wind blows: Children's inferences about force and motion events

Göksun, George, Hirsh-Pasek, and Golinkoff (2013) used force dynamics, or the semantic categories defined by spatial arrays of forces, to study the development of preschoolers' predictions about the outcomes of forces working in concert. The current study extends this approach to problems requiring inferences about causal factors. In total, 30 5- and 6-year-old children were asked to identify and coordinate forces to achieve a result. Problems varied in the number and orientation of forces, mirroring spatial arrays characteristic of categories like prevent (i.e., opposing forces). Children successfully inferred causes of single- and dual-force events, performing best when problems reflected the spatial arrays of forces described in language. Results support force dynamics as a valuable framework for the development of force and motion representations.

Object exploration facilitates 4-month-olds' mental rotation performance

How do infants learn to mentally rotate objects, to imagine them rotating through different viewpoints? One possibility is that development of infants' mental rotation (MR) is facilitated by visual and manual experience with complex objects. To evaluate this possibility, eighty 4-month-olds (40 females, 40 males) participated in an object exploration task with Velcro "sticky mittens" that allow infants too young to grasp objects themselves to nonetheless explore those objects manually as well as visually. These eighty infants also participated in a visual habituation task designed to test MR. Half the infants (Mittens First group) explored the object prior to the MR task, and the other half afterwards (Mittens Second group), to examine the role of immediate prior object experience on MR performance. We compared performance of male and female infants, but found little evidence for sex differences. However, we found an important effect of object exploration: The infants in the Mittens First group who exhibited the highest levels of spontaneous object engagement showed the strongest evidence of MR, but there were no consistent correlations between these measures for infants in the Mittens Second group. These findings suggest an important contribution from object experience to development of MR.

The case of CAUSE: neurobiological mechanisms for grounding an abstract concept

How can we understand causal relationships and how can we understand words such as 'cause'? Some theorists assume that the underlying abstract concept is given to us, and that perceptual correlation provides the relevant hints towards inferring causation from perceived real-life events. A different approach emphasizes the role of actions and their typical consequences for the emergence of the concept of causation and the application of the related term. A model of causation is proposed that highlights the family resemblance between causal actions and postulates that symbols are necessary for binding together the different partially shared semantic features of subsets of causal actions and their goals. Linguistic symbols are proposed to play a key role in binding the different subsets of semantic features of the abstract concept. The model is spelt out at the neuromechanistic level of distributed cortical circuits and the cognitive functions they carry. The model is discussed in light of behavioural and neuroscience evidence, and questions for future research are highlighted. In sum, taking causation as a concrete example, I argue that abstract concepts and words can be learnt and grounded in real-life interaction, and that the neurobiological mechanisms realizing such abstract semantic grounding are within our grasp.This article is part of the theme issue 'Varieties of abstract concepts: development, use and representation in the brain'.

The Efficiency of Infants' Exploratory Play Is Related to Longer-Term Cognitive Development

In this longitudinal study we examined the stability of exploratory play in infancy and its relation to cognitive development in early childhood. We assessed infants' (N = 130, mean age at enrollment = 12.02 months, SD = 3.5 months; range: 5-19 months) exploratory play four times over 9 months. Exploratory play was indexed by infants' attention to novelty, inductive generalizations, efficiency of exploration, face preferences, and imitative learning. We assessed cognitive development at the fourth visit for the full sample, and again at age three for a subset of the sample (n = 38). The only measure that was stable over infancy was the efficiency of exploration. Additionally, infants' efficiency score predicted vocabulary size and distinguished at-risk infants recruited from early intervention sites from those not at risk. Follow-up analyses at age three provided additional evidence for the importance of the efficiency measure: more efficient exploration was correlated with higher IQ scores. These results suggest that the efficiency of infants' exploratory play can be informative about longer-term cognitive development.

Characteristics of brief sticky mittens training that lead to increases in object exploration

The onset of independent prehension marks the beginning of infants' direct interaction with the physical world. The success infants have in contacting objects with their hands and arms can have both visual and auditory consequences; objects may move and collide with other objects or fall onto table surfaces. Seeing and hearing these events could have important consequences for infants' learning about objects and their subsequent behavior toward objects. The current research assessed the effects of brief object manipulation experiences and how a specific characteristic of training, auditory feedback produced by hard plastic toys colliding with a tabletop surface, affects pre-reaching infants' subsequent object exploration. In Experiment 1, infants participated in either active "sticky" mittens training or passive "nonsticky" mittens training with a set of toys; before and after this experience, infants explored a teether. Results showed that infants participating in active training increased looking toward and sustained touching of the teether from pre- to post-training, whereas infants receiving passive training decreased their looking toward and touching of the teether following training. To investigate whether infants' exploration behaviors were related to the amount of auditory feedback produced by the objects during training, in Experiment 2 data were collected from infants who received active sticky mittens training that had either more or less auditory feedback potential. Results showed more robust increases in infants' exploratory activity from pre- to post-training in the more auditory feedback condition compared with infants' exploratory activity in the less auditory feedback condition. These findings support the idea that active control of objects, including experiencing contingent feedback through multiple sensory modalities, promotes the development of object exploration during early infancy.

Plasticity may change inputs as well as processes, structures, and responses

Significant work has documented neuroplasticity in development, demonstrating that developmental pathways are shaped by experience. Plasticity is often discussed in terms of the results of differences in input; differences in brain structures, processes, or responses reflect differences in experience. In this paper, I discuss how developmental plasticity also effectively changes input into the system. That is, structures and processes change in response to input, and those changed structures and processes influence future inputs. For example, plasticity may change the pattern of eye movements to a stimulus, thereby changing which part of the scene becomes the input. Thus, plasticity is not only seen in the structures and processes that result from differences in experience, but also is seen in the changes in the input as those structures and processes adapt. The systematic study of the nature of experience, and how differences in experience shape learning, can contribute to our understanding of neuroplasticity in general.

The modulation of causal contexts in motion processes judgment as revealed by P2 and P3

The evoked response potential (ERP) procedure was used to investigate the representation of motion processes in different causal contexts, such as the collision of two squares or the repulsion of two magnets with like poles facing. Participants were required to judge whether each movement was plausible according to the causal context depicted by the cover story. Three main differences after the movement of the second object were found. First, the amplitudes at 70-170ms (N1) and 170-370ms (P2) elicited by a no-contact condition were more negative than a contact condition in the square context, whereas larger N1 and more positive amplitudes at 370-670ms were elicited by a no-contact condition in the magnet context. Second, larger P2 and more positive amplitudes at 370-670ms were elicited by inconsistent direction relative to consistent condition in the square context, whereas smaller N1 and more positive amplitudes at 370-670ms were elicited by inconsistent direction in the magnet context. Finally, larger P2 and more negative amplitudes at 370-470ms were elicited by plausible conditions relative to implausible conditions in a square context, whereas larger N1 and more positive amplitudes at 370-670ms were elicited by plausible conditions in the magnet context. These results suggested that the conceptual knowledge with different causal contexts have distinct effects on the judgment of objects interactions.

Infants' observation of tool-use events over the first year of life

How infants observe a goal-directed instrumental action provides a unique window into their understanding of others' behavior. In this study, we investigated eye-gaze patterns while infants observed events in which an actor used a tool on an object. Comparisons among 4-, 7-, 10-, and 12-month-old infants and adults reveal changes in infants' looking patterns with age; following an initial face bias, infants' scan path eventually shows a dynamic integration of both the actor's face and the objects on which they act. This shift may mark a transition in infants' understanding of the critical components of tool-use events and their understanding of others' behavior.

Functional neuroanatomy of intuitive physical inference

To engage with the world-to understand the scene in front of us, plan actions, and predict what will happen next-we must have an intuitive grasp of the world's physical structure and dynamics. How do the objects in front of us rest on and support each other, how much force would be required to move them, and how will they behave when they fall, roll, or collide? Despite the centrality of physical inferences in daily life, little is known about the brain mechanisms recruited to interpret the physical structure of a scene and predict how physical events will unfold. Here, in a series of fMRI experiments, we identified a set of cortical regions that are selectively engaged when people watch and predict the unfolding of physical events-a "physics engine" in the brain. These brain regions are selective to physical inferences relative to nonphysical but otherwise highly similar scenes and tasks. However, these regions are not exclusively engaged in physical inferences per se or, indeed, even in scene understanding; they overlap with the domain-general "multiple demand" system, especially the parts of that system involved in action planning and tool use, pointing to a close relationship between the cognitive and neural mechanisms involved in parsing the physical content of a scene and preparing an appropriate action.

Probing the Cultural Constitution of Causal Cognition - A Research Program

To what extent is the way people perceive, represent, and reason about causal relationships dependent on culture? While there have been sporadic attempts to explore this question, a systematic investigation is still lacking. Here, we propose that human causal cognition is not only superficially affected by cultural background, but that it is co-constituted by the cultural nature of the human species. To this end, we take stock of on-going research, with a particular focus on the methodological approaches taken: cross-species comparisons, archeological accounts, developmental studies, cross-cultural, and cross-linguistic experiments, as well as in-depth within-culture analyses of cognitive concepts, processes, and changes over time. We argue that only a combination of these approaches will allow us to integrate different components of cognition, levels of analysis, and points of view—the key requirements for a comprehensive, interdisciplinary research program to advance this field.

Contribution of Embodiment to Solving the Riddle of Infantile Amnesia

At least since the late nineteenth century, researchers have sought an explanation for infantile amnesia (IA)-the lack of autobiographical memories dating from early childhood-and childhood amnesia (CA), faster forgetting of events up until the age of about seven. Evidence suggests that IA occurs across altricial species, and a number of studies using animal models have converged on the hypothesis that maturation of the hippocampus is an important factor. But why does the hippocampus mature at one time and not another, and how does that maturation relate to memory? Our hypothesis is rooted in theories of embodied cognition, and it provides an explanation both for hippocampal development and the end of IA. Specifically, the onset of locomotion prompts the alignment of hippocampal place cells and grid cells to the environment, which in turn facilitates the ontogeny of long-term episodic memory and the end of IA. That is, because the animal can now reliably discriminate locations, location becomes a stable cue for memories. Furthermore, as the mode of human locomotion shifts from crawling to walking, there is an additional shift in the alignment of the hippocampus that marks the beginning of adult-like episodic memory and the end of CA. Finally, given a reduction in self-locomotion and exploration with aging, the hypothesis suggests a partial explanation for cognitive decline with aging.

Emotional experience in music fosters 18-month-olds' emotion-action understanding: a training study

We examine whether emotional experiences induced via music-making promote infants' use of emotional cues to predict others' action. Fifteen-month-olds were randomly assigned to participate in interactive emotion training either with or without musical engagement for three months. Both groups were then re-tested with two violation-of-expectation paradigms respectively assessing their sensitivity to some expressive features in music and understanding of the link between emotion and behaviour in simple action sequences. The infants who had participated in music, but not those who had not, were surprised by music-face inconsistent displays and were able to interpret an agent's action as guided by her expressed emotion. The findings suggest a privileged role of musical experience in prompting infants to form emotional representations, which support their understanding of the association between affective states and action.

Sticky mittens, prickly Velcro, and infants' transition into independent reaching: Response to Williams, Corbetta, and Guan (2015)

Williams, Corbetta, and Guan (2015) report findings on the effects of active and passive motor training in three-month-old infants and argue that passive task exposure is sufficient to encourage future reaching behaviors. In this commentary, we relate these new findings to our body of published work using sticky mittens and describe important differences in the materials and procedures used. In particular, Williams et al. (2015) used modified sticky mittens that allowed infants' fingers to make direct contact with prickly Velcro on the toys, and they used a different training procedure that required infants to discover the hidden functionality of the sticky mittens by themselves. We argue that these differences explain the apparent conflicts between our prior work and the results reported by Williams et al. (2015). The Williams study presented infants with a learning context that was quite different from the one infants encountered in our research, and so it is not surprising that infants in their study showed such different patterns of behavior.

Catching moving objects: Differential effects of background motion on action mode selection and movement control in 6- to 10-month-old infants

In human adults the use of visual information for selecting appropriate modes for action appears to be separate from the use of visual information for the control of movements of which the action is composed (Milner & Goodale, [1995] The visual brain in action; [2008] Neuropsychologia 46:774-785). More specifically, action mode selection primarily relies upon allocentric information, whereas movement control mainly exploits egocentric information. In the present study, we investigated to what degree this division is already present in 6- to 10-month-old infants when reaching for moving objects; that is, whether allocentric information is uniquely exploited for action mode selection (i.e., reaching with one or the other hand) or whether it is also used for movement control (i.e., reaching kinematics). Infants were presented with laterally approaching objects at two speeds (i.e., 20 and 40 cm/s) against a stationary or moving background. Background motion affects allocentric information about the object's velocity relative to its background. Results indicated that object speed constrained both infants' action mode selection and movement control. Importantly, however, the influence of background motion was limited to action mode selection and did not extend to movement control. The findings provide further support for the contention that during early development information usage is--at least to some degree--separated for action mode selection and movement control.

Active Drumming Experience Increases Infants' Sensitivity to Audiovisual Synchrony during Observed Drumming Actions

In the current study, we examined the role of active experience on sensitivity to multisensory synchrony in six-month-old infants in a musical context. In the first of two experiments, we trained infants to produce a novel multimodal effect (i.e., a drum beat) and assessed the effects of this training, relative to no training, on their later perception of the synchrony between audio and visual presentation of the drumming action. In a second experiment, we then contrasted this active experience with the observation of drumming in order to test whether observation of the audiovisual effect was as effective for sensitivity to multimodal synchrony as active experience. Our results indicated that active experience provided a unique benefit above and beyond observational experience, providing insights on the embodied roots of (early) music perception and cognition.

Shifting goals: effects of active and observational experience on infants' understanding of higher order goals

Action perception links have been argued to support the emergence of action understanding, but their role in infants’ perception of distal goals has not been fully investigated. The current experiments address this issue. During the development of means-end actions, infants shift their focus from the means of the action to the distal goal. In Experiment One, we evaluated whether this same shift in attention (from the means to the distal goal) when learning to produce multi-step actions is reflected in infants’ perception of others’ means-end actions. Eight-months-old infants underwent active training in means-end action production and their subsequent analysis of an observed means-end action was assessed in a visual habituation paradigm. Infants’ degree of success in the training paradigm was related to their subsequent interpretation of the observed action as directed at the means versus the distal goal. In Experiment Two, observational and control manipulations provided evidence that these effects depended on the infants’ active engagement in the means-end actions. These results suggest that the processes that give rise to means-end structure in infants’ motor behavior also support the emergence of means-end structure in their analysis of others’ goals.

Understanding the effects of one's actions upon hidden objects and the development of search behaviour in 7-month-old infants

Infants' understanding of how their actions affect the visibility of hidden objects may be a crucial aspect of the development of search behaviour. To investigate this possibility, 7-month-old infants took part in a two-day training study. At the start of the first session, and at the end of the second, all infants performed a search task with a hiding-well. On both days, infants had an additional training experience. The 'Agency group' learnt to spin a turntable to reveal a hidden toy, whilst the 'Means-End' group learnt the same means-end motor action, but the toy was always visible. The Agency group showed greater improvement on the hiding-well search task following their training experience. We suggest that the Agency group's turntable experience was effective because it provided the experience of bringing objects back into visibility by one's actions. Further, the performance of the Agency group demonstrates generalized transfer of learning across situations with both different motor actions and stimuli in infants as young as 7 months.

Mapping the feel of the arm with the sight of the object: on the embodied origins of infant reaching

For decades, the emergence and progression of infant reaching was assumed to be largely under the control of vision. More recently, however, the guiding role of vision in the emergence of reaching has been downplayed. Studies found that young infants can reach in the dark without seeing their hand and that corrections in infants' initial hand trajectories are not the result of visual guidance of the hand, but rather the product of poor movement speed calibration to the goal. As a result, it has been proposed that learning to reach is an embodied process requiring infants to explore proprioceptively different movement solutions, before they can accurately map their actions onto the intended goal. Such an account, however, could still assume a preponderant (or prospective) role of vision, where the movement is being monitored with the scope of approximating a future goal-location defined visually. At reach onset, it is unknown if infants map their action onto their vision, vision onto their action, or both. To examine how infants learn to map the feel of their hand with the sight of the object, we tracked the object-directed looking behavior (via eye-tracking) of three infants followed weekly over an 11-week period throughout the transition to reaching. We also examined where they contacted the object. We find that with some objects, infants do not learn to align their reach to where they look, but rather learn to align their look to where they reach. We propose that the emergence of reaching is the product of a deeply embodied process, in which infants first learn how to direct their movement in space using proprioceptive and haptic feedback from self-produced movement contingencies with the environment. As they do so, they learn to map visual attention onto these bodily centered experiences, not the reverse. We suggest that this early visuo-motor mapping is critical for the formation of visually-elicited, prospective movement control.

Carving the world for language: how neuroscientific research can enrich the study of first and second language learning

Linguistics, psychology, and neuroscience all have rich histories in language research. Crosstalk among these disciplines, as realized in studies of phonology, is pivotal for understanding a fundamental challenge for first and second language learners (SLLs): learning verbs. Linguistic and behavioral research with monolinguals suggests that infants attend to foundational event components (e.g., path, manner). Language then heightens or dampens attention to these components as children map word to world in language-specific ways. Cross-linguistic differences in semantic organization also reveal sources of struggles for SLLs. We discuss how better integrating neuroscience into this literature can unlock additional mysteries of verb learning.

Encouragement is Nothing Without Control: Factors Influencing the Development of Reaching and Face Preference

Four parent-guided training procedures aimed at facilitating independent reaching were compared in 36 three-month-old infants recruited for this study and 36 infants taken from previously published reports. Training procedures systematically varied whether parental encouragement to act on external objects was provided, and whether self-produced experiences of moving an object were present. Reaching behavior was assessed before and after training, and face preference was measured after training by recording infants’ eye gaze in a visual-preference task. Results showed that simultaneous experiences of parental encouragement and self-produced object motion encouraged successful reaching and face preference. Neither experience in isolation was effective, indicating that both external encouragement and self-produced action experiences are necessary to facilitate successful reaching. However, experiences with self-produced object motion increased infants’ face preference. This result provides evidence for a developmental link between self-produced motor experiences and the emergence of face preference in three-month-old infants.

The joint role of trained, untrained, and observed actions at the origins of goal recognition

Recent findings across a variety of domains reveal the benefits of self-produced experience on object exploration, object knowledge, attention, and action perception. The influence of active experience may be particularly important in infancy, when motor development is undergoing great changes. Despite the importance of self-produced experience, we know that infants and young children are eventually able to gain knowledge through purely observational experience. In the current work, three-month-old infants were given experience with object-directed actions in one of three forms and their recognition of the goal of grasping actions was then assessed in a habituation paradigm. All infants were given the chance to manually interact with the toys without assistance (a difficult task for most three-month-olds). Two of the three groups were then given additional experience with object-directed actions, either through active training (in which Velcro mittens helped infants act more efficiently) or observational training. Findings support the conclusion that self-produced experience is uniquely informative for action perception and suggest that individual differences in spontaneous motor activity may interact with observational experience to inform action perception early in life.

Learning from their own actions: the unique effect of producing actions on infants' action understanding

Prior research suggests that infants' action production affects their action understanding, but little is known about the aspects of motor experience that render these effects. In Study 1, the relative contributions of self-produced (n = 30) and observational (n = 30) action experience on 3-month-old infants' action understanding was assessed using a visual habituation paradigm. In Study 2, generalization of training to a new context was examined (n = 30). Results revealed a unique effect of active over observational experience. Furthermore, findings suggest that benefits of trained actions do not generalize broadly, at least following brief training.

First-person action experience reveals sensitivity to action efficiency in prereaching infants

Do infants learn to interpret others' actions through their own experience producing goal-directed action, or does some knowledge of others' actions precede first-person experience? Several studies report that motor experience enhances action understanding, but the nature of this effect is not well understood. The present research investigates what is learned during early motoric production, and it tests whether knowledge of goal-directed actions, including an assumption that actors maximize efficiency given environmental constraints, exists before experience producing such actions. Three-month-old infants (who cannot yet effectively reach for and grasp objects) were given novel experience retrieving objects that rested on a surface with no barriers. They were then shown an actor reaching for an object over a barrier and tested for sensitivity to the efficiency of the action. These infants showed heightened attention when the agent reached inefficiently for a goal object; in contrast, infants who lacked successful reaching experience did not differentiate between direct and indirect reaches. Given that the infants could reach directly for objects during training and were given no opportunity to update their actions based on environmental constraints, the training experience itself is unlikely to have provided a basis for learning about action efficiency. We suggest that infants apply a general assumption of efficient action as soon as they have sufficient information (possibly derived from their own action experience) to identify an agent's goal in a given instance.

Size matters: how age and reaching experiences shape infants' preferences for different sized objects

Looking and reaching preferences for different-sized objects were examined in 4-5- and 5-6-month-old infants. Infants were presented with pairs of different sized cylinders and preferences were analyzed by age and reaching status. Outcome variables included looking and touching time for each object, first look, and first touch. Significant three-way interactions with age and reaching status were found for both infants' looking and touching duration. Four-5- and 5-6-month-olds with less reaching experience spent more time visually and manually exploring larger objects. In contrast, 5-6-month-olds with more reaching experience spent more time looking at and touching smaller objects, despite a first look and first touch preference for the largest object. Initially, looking and reaching preferences seem to be driven by mechanisms responding to general visual salience independent of an object's potential for manual action. Once reaching skills emerge, infants begin to use visual information to selectively choose smaller, more graspable objects as exploration targets.

Forces and motion: how young children understand causal events

How do children evaluate complex causal events? This study investigates preschoolers' representation of force dynamics in causal scenes, asking whether (a) children understand how single and dual forces impact an object's movement and (b) this understanding varies across cause types (Cause, Enable, Prevent). Three-and-a half- to 5.5-year-olds (n = 60) played a board game in which they were asked to predict the endpoint of a ball being acted upon by one or two forces. Children mostly understood the interactions of forces underlying each type of cause; only 5.5-year-olds could integrate two contradictory forces. Children perceive force interactions underlying causal events, but some concepts might not be fully understood until later in childhood. This study provides a new way of thinking about causal relations.

Getting the closer object? An information-based dissociation between vision for perception and vision for movement in early infancy

In human adults two functionally and neuro-anatomically separate systems exist for the use of visual information in perception and the use of visual information to control movements (Milner & Goodale, 1995, 2008). We investigated whether this separation is already functioning in the early stages of the development of reaching. To this end, 6- and 7-month-old infants were presented with two identical objects at identical distances in front of an illusory Ponzo-like background that made them appear to be located at different distances. In two further conditions without the illusory background, the two objects were presented at physically different distances. Preferential reaching outcomes indicated that the allocentric distance information contained in the illusory background affected the perception of object distance. Yet, infants' reaching kinematics were only affected by the objects' physical distance and not by the perceptual distance manipulation. These findings were taken as evidence for the two-visual systems, as proposed by Milner and Goodale (2008), being functional in early infancy. We discuss the wider implications of this early dissociation.

Measuring preschoolers' superstitious tendencies

Superstitious behaviors have been studied extensively in adults and non-human species, but have not been systematically assessed in children. The purpose of the study is to develop and validate a method of measuring superstitious tendencies in young children based on an established learning paradigm. In two studies, 3-5-year-olds tapped a computer to make a target image appear. On half the trials, a sensory stimulus appeared at a random time before the target. Superstitious tendencies were measured by change in tapping during the presence of the sensory stimulus. Children's proportion of tapping increased during the presence of the sensory stimulus, indicating that children associated the sensory stimulus with the appearance of the target image, even though the two stimuli were not causally related. Implications for the development of superstitious tendencies and children's causal knowledge are discussed.

Correspondences between what infants see and know about causal and self-propelled motion

The associative learning account of how infants identify human motion rests on the assumption that this knowledge is derived from statistical regularities seen in the world. Yet, no catalog exists of what visual input infants receive of human motion, and of causal and self-propelled motion in particular. In this manuscript, we demonstrate that the frequency with which causal agency and self-propelled motion appear in the visual environment predicts infants' understanding of these motions. In an observational study, an infant wearing a head-mounted camera saw people act as agents in causal events three times more often than he saw people engaged in self-propelled motion. Subsequent experiments with the habituation paradigm revealed that infants begin to generalize self-propulsion to agents in causal events between 10 and 14 months of age. However, infants cannot generalize causal agency to a self-propelled object at 14 or 18 months unless the object exhibits additional cues to animacy. The results are discussed within a domain-general framework of learning about human action.