Experience matters: the impact of doing versus watching on infants' subsequent perception of tool-use events

Prior work suggests that active experience affects infants' understanding of simple actions. The present studies compared the impact of active and observational experience on infants' ability to identify the goal of a novel tool-use event. Infants either received active training and practice in using a cane to retrieve an out-of-reach toy or had matched observational experience before taking part in a habituation paradigm that we used to assess infants' ability to identify the goal of another person's tool-use acts. Active training alone facilitated 10-month-old infants' ability to identify the goal of the tool-use event. Active experience using tools may enable infants to build motor representations of tool-use events that subsequently guide action perception and support action understanding.     

Humour production may enhance observational learning of a new tool-use action in 18-month-old infants

Many studies have shown that making children laugh enhances certain cognitive capacities such as attention, motivation, perception and/or memory, which in turn enhance learning. However, no study thus far has investigated whether laughing has an effect on learning earlier in infancy. The goal of this study was to see whether using humour with young infants in a demonstration of a complex tool-use task can enhance their learning. Fifty-three 18-month-old infants participated in this study and were included either in a humorous or a control demonstration group. In both groups infants observed an adult using a tool to retrieve an out-of-reach toy. What differed between groups was that in the humorous demonstration group, instead of playing with the toy, the adult threw it on the floor immediately after retrieval. The results show that infants who laughed at the demonstration in the humorous demonstration group reproduced significantly more frequent target actions than infants who did not laugh and those in the control group. This effect is discussed with regard to individual differences in terms of temperament and social capacities as well as positive emotion and dopamine release.     

The emergence of tool use during the second year of life

Despite a growing interest in the question of tool-use development in infants, no study so far has systematically investigated how learning to use a tool to retrieve an out-of-reach object progresses with age. This was the first aim of this study, in which 60 infants, aged 14, 16, 18, 20, and 22months, were presented with an attractive toy and a rake-like tool. There were five conditions of spatial relationships between the toy and the tool, going from the toy and tool being connected to there being a large spatial gap between them. A second aim of the study was to evaluate at what age infants who spontaneously fail the task can learn this complex skill by being given a demonstration from an adult. Results show that even some of the youngest infants could spontaneously retrieve the toy when it was presented inside and touching the top part of the tool. In contrast, in conditions with a spatial gap, the first spontaneous successes were observed at 18months, suggesting that a true understanding of the use of the tool has not been fully acquired before that age. Interestingly, it is also at 18months that infants began to benefit from the demonstration in the conditions with a spatial gap. The developmental steps for tool use observed here are discussed in terms of changes in infants' ability to attend to more than one item in the environment. The work provides insight into the progressive understanding of tool use during infancy and into how observational learning improves with age.     

Infants’ developing expectations of possible and impossible tool-use events between ages 8 and 12 months

Infants’ developing causal expectations for the outcome of a simple tool-use event from ages 8 to 12 months were investigated. Causal expectations were studied by comparing infants’ developing tool-use actions (i.e. as tool-use agents) with their developing perceptual reactions (i.e. as tool-use observers) to possible and impossible tool-use events. In Experiment 1, tool-use actions were studied by presenting infants, ages 8 and 12 months, with tool-use object-retrieval problems. In Experiment 2, a second age-matched sample of infants watched a comparable series of possible and impossible tool-use events in which a tool was used to retrieve a goal-object. Two core related findings were made. First, infants’ causal action and causal perception develop in parallel. In both action and perception, supporting tool-use develops before surrounding tool-use. Second, infants’ tool-use action develops before their causal perception of comparable tool-use events. The findings support the constructivist hypothesis that infants’ causal actions may develop before and inform their causal perceptions.     

Infant's perception of goal-directed actions performed by a mechanical device

The present work investigated whether by the end of the first year, infants interpret actions performed by a mechanical device as goal-directed and why they would do so. Using a modified version of the Woodward (1998) habituation paradigm, 9- and 12-month-old infants were tested in a condition in which they saw a mechanical claw performing an action (Study 1). When infants viewed the claw grasping and transporting objects to the back of a stage, 12-month-old but not 9-month-old infants interpreted the action as goal-directed. In Study 2, 9-month-olds received prior to habituation an information phase showing infants how a human held and operated the claw. This enrichment of infants’ knowledge enabled 9-month-old infants to interpret the action display as goal-directed. The role of the developing means-end understanding and tool-use for infants’ interpretation of actions performed by a mechanical device is discussed.     

Outcome-based observational learning in human infants

Previous work shows that infants manifest emulation learning in the use of end-state information. Outcome-based emulation has been interpreted as affordance learning or goal attribution. The present paper explores whether these two learning possibilities might be related. In 3 experiments, 17-month-old infants (N = 180) were presented with action outcomes across a variety of contexts and tasks: They observed either the full demonstration or the model's starting and final postures, plus the initial and end states of the object, or the latter portion of the foregoing display, or the end state of the object alone. The tasks included combinatory, noncombinatory, and body movement acts. Infants reproduced observed outcomes most often by observing the full demonstration. A similar effect was attained by exposure to both posture and configuration changes, but the effect was subject to the combinatory nature of the apparatus. In contrast, performance was less efficient after seeing the object's end state alone, suggesting that infants in the previous conditions did not simply emulate in association with the affordances. These findings support the notion that goal attribution based on sensitivity to bodily cues is reliant on the clarity of the affordances of a task.     

Observing inefficient action can induce infant preference and learning

‘Motionese’ can be defined as an exaggerated and repetitive action. It induces preference and learning in infants. However, which action component of motionese promotes infants’ preference and learning remains largely unknown. In this study, we focused on inefficiency and toward-ness of action. Our study demonstrates that observing an inefficient holding out action can induce a visual preference in 4-month-old infants and learning in 10-month-old infants through eight experiments (N = 192). We found that when infants observe inefficient holding out action, the action attracts their attention and facilitates learning about the identity of the toy object accompanying it, especially when people direct inefficient actions towards them. Our findings indicate that both action efficiency and toward-ness may be key factors in infant learning.     

The role of action effects in 12-month-olds' action control: a comparison of televised model and live model

The present study investigated differences in infant imitation after watching a televised model and a live model and addressed the issue of whether action effects influence infants’ action control in both cases. In a 2 × 2 design, 12-month-old infants observed a live or a televised model performing a three-step action sequence, in which either the 2nd or the 3rd action step was combined with an acoustical action effect. We assumed that infants would use the observed action-effect relations for their own action control in the test phase afterwards. Even though results exhibited differences in the absolute amount of imitation between the two demonstration groups, both groups showed similar result patterns regarding the action effect manipulation: infants imitated the action step that was followed by a salient action effect more often and mostly as the first target action, emphasizing the important role of action effects in infants’ action control.     

The role of frequency information and teleological reasoning in infants' and adults' action prediction

This study investigates the contribution of frequency learning and teleological reasoning to action prediction in 9-month-old infants and adults. Participants observed how an agent repeatedly walked to a goal while taking the longer of 2 possible paths, as the shorter and more efficient path was impassable. In the subsequent test phase, both paths were passable. In the 1st test trial, infants and adults anticipated the agent to take the longer path. Unlike adults, infants kept anticipating movements to the longer path even after observing that the agent now took the more efficient path, indicating that the frequency of previous observations dominates action prediction. These results provide evidence, contrary to existing claims in the developmental literature, that frequency learning underlies action prediction in infancy, whereas teleological reasoning might gain importance later on in life.     

The ghost condition: imitation versus emulation in young children's observational learning

Although observational learning by children may occur through imitating a modeler's actions, it can also occur through learning about an object's dynamic affordances--a process that M. Tomasello (1996) calls "emulation." The relative contributions of imitation and emulation within observational learning were examined in a study with 14- to 26-month-old children. The effectiveness of a "ghost" condition, in which the effective operation of the means apparatus was seen to occur without human agency, was compared with that of a standard modeling procedure in which the child saw an experimenter demonstrate the means action. The ghost condition was as likely to encourage observational learning as was the modeling condition; indeed, performance in the ghost condition was significantly better. The role of emulation in the development of observational learning is discussed in the context of a possible form of goal directedness without agency.     

Emergent Goal-Anticipatory Gaze in Infants via Event-Predictive Learning and Inference

From about 7 months of age onward, infants start to reliably fixate the goal of an observed action, such as a grasp, before the action is complete. The available research has identified a variety of factors that influence such goal-anticipatory gaze shifts, including the experience with the shown action events and familiarity with the observed agents. However, the underlying cognitive processes are still heavily debated. We propose that our minds (i) tend to structure sensorimotor dynamics into probabilistic, generative event-predictive, and event boundary predictive models, and, meanwhile, (ii) choose actions with the objective to minimize predicted uncertainty. We implement this proposition by means of event-predictive learning and active inference. The implemented learning mechanism induces an inductive, event-predictive bias, thus developing schematic encodings of experienced events and event boundaries. The implemented active inference principle chooses actions by aiming at minimizing expected future uncertainty. We train our system on multiple object-manipulation events. As a result, the generation of goal-anticipatory gaze shifts emerges while learning about object manipulations: the model starts fixating the inferred goal already at the start of an observed event after having sampled some experience with possible events and when a familiar agent (i.e., a hand) is involved. Meanwhile, the model keeps reactively tracking an unfamiliar agent (i.e., a mechanical claw) that is performing the same movement. We qualitatively compare these modeling results to behavioral data of infants and conclude that event-predictive learning combined with active inference may be critical for eliciting goal-anticipatory gaze behavior in infants.     

Crawling is associated with more flexible memory retrieval by 9-month-old infants

In the present experiment, we used a deferred imitation paradigm to explore the effect of crawling on memory retrieval by 9-month-old human infants. Infants observed an experimenter demonstrate a single target action with a novel object and their ability to reproduce that action was assessed after a 24-hr delay. Some infants were tested with the demonstration stimulus in the demonstration context and some infants were tested with a different stimulus in a different context. Half of the infants in each test condition were crawling at the time of participation and half were not. Both crawling and non-crawling infants exhibited retention when tested with the demonstration stimulus in the demonstration context, but only infants who were crawling by 9 months of age exhibited retention when tested with a different stimulus in a different context. These findings demonstrate that the onset of independent locomotion is associated with more flexible memory retrieval during the first year of life.     

Infants’ understanding of everyday social interactions: A dual process account

Six- and 12-month-old infant’s eye movements were recorded as they observed feeding actions being performed in a rational or non-rational manner. Twelve-month-olds fixated the goal of these actions before the food arrived (anticipation); the latency of these gaze shifts being dependent (r = .69) on infants life experience being feed. In addition, 6- and 12-month-olds dilated their pupil during observation of non-rational feeding actions. This effect could not be attributed to light differences or differences in familiarity, but was interpreted to reflect sympathetic-like activity and arousal caused by a violation of infant’s expectations about rationality. We argue that evaluation of rationality requires less experience than anticipations of action goals, suggesting a dual process account of preverbal infants’ everyday action understanding.     

Visual experience enhances infants' use of task-relevant information in an action task

Four experiments examined whether infants' use of task-relevant information in an action task could be facilitated by visual experience in the laboratory. Twelve- but not 9-month-old infants spontaneously used height information and chose an appropriate (taller) cover in search of a hidden tall toy. After watching examples of covering events in a teaching session, 9-month-old infants succeeded in an action task that involved the same event category; learning was not generalized to events from a different category. The present results demonstrate that learning through visual experience can be transferred to infants' subsequent actions. These findings shed light on the link between perception and action in infancy.     

Changes in infant visual attention when observing repeated actions

Infants’ early visual preferences for faces, and their observational learning abilities, are well-established in the literature. The current study examines how infants’ attention changes as they become increasingly familiar with a person and the actions that person is demonstrating. The looking patterns of 12- (n = 61) and 16-month-old infants (n = 29) were tracked while they watched videos of an adult presenting novel actions with four different objects three times. A face-to-action ratio in visual attention was calculated for each repetition and summarized as a mean across all videos. The face-to-action ratio increased with each action repetition, indicating that there was an increase in attention to the face relative to the action each additional time the action was demonstrated. Infant’s prior familiarity with the object used was related to face-to-action ratio in 12-month-olds and initial looking behavior was related to face-to-action ratio in the whole sample. Prior familiarity with the presenter, and infant gender and age, were not related to face-to-action ratio. This study has theoretical implications for face preference and action observations in dynamic contexts.     

Twelve- and 18-month-olds copy actions in terms of goals

In the context of an imitation game, 12- and 18-month-old infants saw an adult do such things as make a toy mouse hop across a mat (with sound effects). In one condition (House), the adult ended by placing the mouse in a toy house, whereas in another condition (No House) there was no house present at the final location. Infants at both ages usually simply put the mouse in the house (ignoring the hopping motion and sound effects) in the House condition, presumably because they interpreted the adult's action in terms of this final goal and so ignored the behavioral means. In contrast, infants copied the adult's action (both the hopping motion and the sound effects) when no house was present, presumably because here infants saw the action itself as the adult's only goal. From very early, infants' social learning is flexible: infants focus on and copy either the end or the means of an adult action as required by the context.     

Guided by Intention: Preschoolers' Imitation Reflects Inferences of Causation

Object use is a ubiquitous characteristic of the human species, and learning how objects function is a fundamental part of development. In this article the authors examine the role that intentionality plays in children's understanding of causal relationships during observational learning of object use. Children observed demonstrations in which causally irrelevant and causally relevant actions were performed to achieve a desired goal. The intentionality of these actions was manipulated using verbal markers. Irrelevant actions were performed either intentionally (“There!”) or accidentally (“Whoops! I didn't mean to do that!”). Three-, 4-, and 5-year-olds, but not 2-year-olds, were less likely to imitate causally irrelevant actions performed accidentally than when they were performed intentionally. This suggests that older children used intentionality to guide causal inference and perceived intentional actions as causally effective and accidental actions as causally ineffective. Findings are discussed from an evolutionary perspective in relation to the cultural transmission of tool-use knowledge.     

Infants' attention to an adult's demonstration of object functions: evidence for a comparator process

The present study was motivated by a concern with the cognitive processes that infants bring to bear on stimulation offered by adults. As previous studies have highlighted the importance of parental stimulation with objects, this study consisted of an experimental investigation of this context of stimulation. It was hypothesized that adults' actions that demonstrate the functions of toys activate a comparator process in 9-month-old infants. It was predicted that prior exposure to the toy in a stationary state would increase attention to a demonstrative action, as the comparator process requires time over and above the local processing of an event. This prediction was borne out: 9-month-olds infants' attention to the demonstration of the functions of a toy was augmented by immediate prior exposure to the toy in a stationary state. By contrast, attention to other actions which did not demonstrate specific functions was either significantly reduced by prior exposure to the toy, or unaffected. Moreover, 16-month-olds who are better able to perform a broad range of actions with objects, did not show increased attention to a demonstration of functions when prior exposure to the toy was provided. © 1998 John Wiley & Sons, Ltd.     

Labels Facilitate Infants' Comparison of Action Goals

Understanding the actions of others depends on the insight that these actions are structured by intentional relations. In a number of conceptual domains, comparison with familiar instances has been shown to support children's and adults' ability to discern the relational structure of novel instances. Recent evidence suggests that this process supports infants' analysis of others' goal-directed actions (Gerson &; Woodward, 2012 Gerson , S. , &; Woodward , A. L. ( 2012 ). A claw is like my hand: Comparison supports goal analysis in infants . Cognition , 122 , 181 – 192 . doi: 10.1016/j.cognition.2011.10.014 [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). The current studies evaluated whether labeling, which has been shown to support relational learning in other domains, also supports infants' sensitivity to the goal structure of others' actions. Ten-month-old infants observed events in which a familiar action, grasping, was aligned (simultaneously presented) with a novel tool-use action, and both actions were accompanied by a matched label. Following this training, infants responded systematically to the goal structure of the tool-use actions in a goal imitation paradigm. In control conditions, when the aligned actions were accompanied by nonword vocalizations, or when labeling occurred without aligned actions, infants did not respond systematically to the tool-use action. These findings indicate that labels supported infants' comparison of the aligned actions, and this comparison facilitated their understanding of the novel action as goal-directed.     

Primacy of information about means selection over outcome selection in goal attribution by infants

It has been shown that, when observing an action, infants can rely on either outcome selection information (i.e., actions that express a choice between potential outcomes) or means selection information (i.e., actions that are causally efficient toward the outcome) in their goal attribution. However, no research has investigated the relationship between these two types of information when they are present simultaneously. In an experiment that addressed this question directly, we found that when outcome selection information could disambiguate the goal of the action (e.g., the action is directed toward one of two potential targets), but means selection information could not (i.e., the action is not efficiently adjusted to the situational constraints), 7- and 9-month-old infants did not attribute a goal to an observed action. This finding suggests that means selection information takes primacy over outcome selection information. The early presence of this bias sheds light on the nature of the notion of goal in action understanding.