Imitating step by step: a detailed analysis of 9- to 15-month-olds' reproduction of a three-step action sequence

To investigate what infants around their first birthday learn from observing an action sequence, 9- to 15-month-olds' imitative behavior was compared in three conditions: a demonstration group watched three target action steps and a final outcome, a control group observed only the third step and final outcome, and a baseline group received no demonstration. After a short delay, the demonstration infants of all ages produced more target actions than the control and baseline infants. Moreover, the latency to the first step was shortest in the demonstration condition. Data about the performance of the single steps in each age sample revealed which target actions were novel to the infants, and which steps were learned by observation. Infants in the control condition did not generate the unseen target action steps. It is concluded that infants' memory capacity and their ability to encode action-effect relations contribute to their imitation of an action sequence.     

Motion tracking of parents’ infant‐ versus adult‐directed actions reveals general and action‐specific modulations

Parents tend to modulate their movements when demonstrating actions to their infants. Thus far, these modulations have primarily been quantified by human raters and for entire interactions, thereby possibly overlooking the intricacy of such demonstrations. Using optical motion tracking, the precise modulations of parents’ infant‐directed actions were quantified and compared to adult‐directed actions and between action types. Parents demonstrated four novel objects to their 14‐month‐old infants and adult confederates. Each object required a specific action to produce a unique effect (e.g. rattling). Parents were asked to demonstrate an object at least once before passing it to their demonstration partner, and they were subsequently free to exchange the object as often as desired. Infants’ success at producing the objects’ action‐effects was coded during the demonstration session and their memory of the action‐effects was tested after a several‐minute delay. Indicating general modulations across actions, parents repeated demonstrations more often, performed the actions in closer proximity and demonstrated action‐effects for longer when interacting with their infant compared to the adults. Meanwhile, modulations of movement size and velocity were specific to certain action‐effect pairs. Furthermore, a ‘just right’ modulation of proximity was detected, since infants’ learning, memory, and parents’ prior evaluations of their infants’ motor abilities, were related to demonstrations that were performed neither too far from nor too close to the infants. Together, these findings indicate that infant‐directed action modulations are not solely overall exaggerations but are dependent upon the characteristics of the to‐be learned actions, their effects, and the infant learners.     

The social context of imitation in infancy

Infants increasingly generalize deferred imitation across environmental contexts between 6 and 18 months of age. In three experiments with 126 6-, 9-, 12-, 15-, and 18-month-olds, we examined the role of the social context in deferred imitation. One experimenter demonstrated target actions on a hand puppet, and a second experimenter tested imitation 24h later. When the second experimenter was novel, infants did not exhibit deferred imitation at any age; when infants were preexposed to the second experimenter, all of them did. Imitating immediately after the demonstration also facilitated deferred imitation in a novel social context at all ages but 6 months. Infants' pervasive failure to exhibit deferred imitation in a novel social context may reflect evolutionary selection pressures that favored conservative behavior in social animals.     

The influence of electronic sound effects on learning from televised and live models

Infants rapidly accrue information via imitation from multiple sources, including television and electronic toys. In two experiments, we examined whether adding sound effects to video or live demonstrations would influence imitation by 6-, 12-, and 18-month-olds. In Experiment 1, we added matching and mismatching sound effects to target actions presented by a televised model. We found that 6-month-olds reproduced the target actions regardless of whether the sound effects were matched or mismatched, whereas 12- and 18-month-olds reproduced the actions only when the sound effects were matched. In Experiment 2, we added matching sound effects to target actions presented by a live model. The addition of sound effects disrupted imitation performance by 6-, 12-, and 18-month-olds. Overall, imitation provides a clear behavioral measure of rapid changes in learning from television and electronic toys during infancy. These findings have practical implications for producers and parents regarding learning in the digital age and theoretical implications regarding the development of integrated action-perception representational systems.     

Sensitivity to communicative relevance tells young children what to imitate

How do children decide which elements of an action demonstration are important to reproduce in the context of an imitation game? We tested whether selective imitation of a demonstrator’s actions may be based on the same search for relevance that drives adult interpretation of ostensive communication. Three groups of 18‐month‐old infants were shown a toy animal either hopping or sliding (action style) into a toy house (action outcome), but the communicative relevance of the action style differed depending on the group. For the no prior information group, all the information in the demonstration was new and so equally relevant. However, for infants in the ostensive prior information group, the potential action outcome was already communicated to the infant prior to the main demonstration, rendering the action style more relevant. Infants in the ostensive prior information group imitated the action style significantly more than infants in the no prior information group, suggesting that the relevance manipulation modulated their interpretation of the action demonstration. A further condition (non‐ostensive prior information) confirmed that this sensitivity to new information is only present when the ‘old’ information had been communicated, and not when infants discovered this information for themselves. These results indicate that, like adults, human infants expect communication to contain relevant content, and imitate action elements that, relative to their current knowledge state or to the common ground with the demonstrator, is identified as most relevant.     

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.     

A claw is like my hand: comparison supports goal analysis in infants

Understanding the intentional relations in others' actions is critical to human social life. Origins of this knowledge exist in the first year and are a function of both acting as an intentional agent and observing movement cues in actions. We explore a new mechanism we believe plays an important role in infants' understanding of new actions: comparison. We examine how the opportunity to compare a familiar action with a novel, tool use action helps 7- and 10-month-old infants extract and imitate the goal of a tool use action. Infants given the chance to compare their own reach for a toy with an experimenter's reach using a claw later imitated the goal of an experimenter's tool use action. Infants who engaged with the claw, were familiarized with the claw's causal properties, or learned the associations between claw and toys (but did not align their reaches with the claw's) did not imitate. Further, active participation in the familiar action to be compared was more beneficial than observing a familiar and novel action aligned for 10-month-olds. Infants' ability to extract the goal-relation of a novel action through comparison with a familiar action could have a broad impact on the development of action knowledge and social learning more generally.     

The reliability of a model influences 14-month-olds’ imitation

Human infants have an enormous amount to learn from others to become full-fledged members of their culture. Thus, it is important that they learn from reliable, rather than unreliable, models. In two experiments, we investigated whether 14-month-olds (a) imitate instrumental actions and (b) adopt the individual preferences of a model differently depending on the model’s previous reliability. Infants were shown a series of videos in which a model acted on familiar objects either competently or incompetently. They then watched as the same model demonstrated a novel action on an object (imitation task) and preferentially chose one of two novel objects (preference task). Infants’ imitation of the novel action was influenced by the model’s previous reliability; they copied the action more often when the model had been reliable. However, their preference for one of the novel objects was not influenced by the model’s previous reliability. We conclude that already by 14 months of age, infants discriminate between reliable and unreliable models when learning novel actions.     

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

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

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.     

Unwilling versus unable: infants' understanding of intentional action

Infants experienced a female adult handling them toys. Sometimes, however, the transaction failed, either because the adult was in various ways unwilling to give the toy (e.g., she teased the child with it or played with it herself) or else because she was unable to give it (e.g., she accidentally dropped it). Infants at 9, 12, and 18 months of age reacted with more impatience (e.g., reaching, looking away) when the adult was unwilling to give them the toy than when she was simply unable to give it. Six-month-olds, in contrast, showed no evidence of this differentiation. Because infants' behavioral responses were appropriately adapted to different kinds of intentional actions, and because the adult's actions sometimes produced results that did not match her goal (when having accidents or failed attempts), these findings provide especially rich evidence that infants first begin to understand goal-directed action at around 9 months of age.     

Potentiation in young infants: The origin of the prior knowledge effect?

In two experiments with 6-month-old infants, we found that prior learning of an operant task (remembered for 2 weeks) mediated new learning of a modeling event (remembered for only 1 day) and increased its recall. Infants first learned to associate lever pressing with moving a toy train housed in a large box. One or 2 weeks later, three target actions were modeled on a hand puppet while the train box (a retrieval cue) was in view. Merely retrieving the train memory strengthened it, and simultaneously pairing its retrieved memory with the modeled actions potentiated their learning and recall. When paired 1 week later, deferred imitation increased from 1 day to 4 weeks; when paired 2 weeks later, it increased from 1 day to 6 weeks. The striking parallels between potentiated learning in infants and the prior knowledge effect in adults suggests that the prior knowledge effect originates in early infancy.     

Do as I do: 7-month-old infants selectively reproduce others' goals

In the current study, we tested whether 7-month-old infants would selectively imitate the goal-relevant aspects of an observed action. Infants saw an experimenter perform an action on one of two small toys and then were given the opportunity to act on the toys. Infants viewed actions that were either goal-directed or goal-ambiguous, and that represented either completed or uncompleted goals. Infants reproduced the goal of the experimenter only in those cases where the action was goal-directed, in both the complete and incomplete goal conditions. These results provide the first evidence that infants as young as 7 months of age selectively imitate actions based on their goal-directedness, and that they are able to analyze the goals of even uncompleted actions. Even during the first year of life, infants' sensitivity to goal-directed action is expressed not only in their responses in visual habituation procedures, but also in their overt actions.     

Infants' imitation of goal-directed actions: the role of movements and action effects

This paper reviews studies on infants' imitation of goal-directed actions in the first two years of life. Special emphasis is given to the role of the two observable components of an action, that is, the movement and the action effects, on infants' replication of target actions. The reviewed studies provide evidence that infants benefit most from a full demonstration of both movements and effects. If movements are demonstrated in isolation, infants may encode this information, but they preferentially reproduce actions that lead to salient effects. If action effects are presented in isolation, infants younger than 19 months usually fail to emulate the unseen movements that would be necessary to produce these effects. Infants' ability to predict action effects or to infer unseen movements from incomplete demonstrations improves substantially at the end of the second year of life. It is concluded that the capability to learn relations between movements and action effects by observation, and the knowledge about movement-effect relations acquired so far, may be important factors underlying the developmental changes in infants' imitation of goal-directed actions.     

Music interferes with learning from television during infancy

Infants are frequently exposed to music during daily activities, including free play, and while viewing infant‐directed videotapes that contain instrumental music soundtracks. In Experiment 1, an instrumental music soundtrack was played during a live or televised demonstration to examine its effects on deferred imitation by 6‐, 12‐, and 18‐month‐old infants. Transfer of information was indexed via deferred imitation of the target actions following a 24‐h delay. For half the infants, the music context was also reinstated at the time of test. Performance by experimental groups was compared to that of a baseline control group that participated in the test session without prior exposure to the demonstration. Imitation performance was above baseline for the live groups but not for the video groups regardless of age or the music context at test. In Experiment 2, we added matched sound effects to the video demonstration and infants performed above baseline. We conclude that the music track creates additional cognitive load, disrupts selective attention to the target actions and inhibits transfer of learning from television of the imitation task. Music may impair an infant's ability to translate information from a two‐dimensional to three‐dimensional world even if the auditory context remains the same. Copyright © 2010 John Wiley & Sons, Ltd.     

Does texting interrupt imitation learning in 19-month-old infants?

Observed disruptions to parent-child interactions during parental media use, such as texting, have been termed technoference. For example, when a language learning interaction was disrupted by a phone call, toddlers were less likely to acquire the word. Other studies demonstrated that parents often exhibit a still face while silently reading information on their cell phones. In the present study, the effect of a text interruption on infant imitation learning was examined. Parents demonstrated three target actions to their infants and then infants were given the opportunity to repeat those interactions. The actions were demonstrated four times. Text interruptions occurred before or between demonstrations. Performance of these groups was compared to a baseline control group where the infant did not see a demonstration of the target actions and a no-interruption group where the parents demonstrated the target actions four times without interruption. Parents were randomly assigned to three conditions, interruption-first condition, one-interruption condition, or three-interruptions condition. Infant behavior was measured during the interruptions. Across text interruption groups parents exhibited high levels of still face during the interruptions (77 %). However, infants in all 3 interruption groups performed significantly above the baseline control indicating learning despite the interruptions. Higher reported maternal reliance on the smartphone was related to poorer imitation performance overall. In contrast, when parents reported that they found it easier to multi-task infant imitation rates were higher. These findings indicate that infants can learn under conditions of brief technoference and that individual differences in family media ecology are associated with learning.     

Mediated imitation in 6-month-olds: remembering by association

In two experiments with 72 6-month-olds, we examined whether associating an imitation task with an operant task affects infants' memory for either task. In Experiment 1, infants who imitated target actions that were modeled for 60 s on a hand puppet remembered them for only 1 day. We hypothesized that if infants associated the puppet imitation task with a longer-remembered operant task, then they might remember it longer too. In Experiment 2, infants learned to press a lever to activate a miniature train-a task 6-month-olds remember for 2 weeks-and saw the target actions modeled immediately afterward. These infants successfully imitated for up to 2 weeks, but only if the train memory was retrieved first. A follow-up experiment revealed that the learned association was bidirectional. This is the first demonstration of mediated imitation in 6-month-olds across two very different paradigms and reveals that associations are an important means of protracting memories.     

Relational information processing of novel unrelated actions by infants

Declarative memory in infants is often assessed via deferred imitation. Not much is known about the information processing basis of the memory effect found in these experiments. While in the typical deferred imitation study the order of actions remains the same during demonstration and retrieval, in two experiments with n=30 respective n=25, 10- and 11-month-old infants, the order of novel unrelated actions in demonstration and retrieval was varied (same, reversed, mixed). This allowed a separation of item-specific from item-relational information processing. In both experiments best memory performance was found when the order of target actions remained the same during encoding and recall, demonstrating that infants seem to rely on item-specific as well as item-relational information which has to be ad hoc constructed while encoding.     

Infants' symbolic comprehension of actions modeled with toy replicas

While very young children's understanding of objects as symbols for other entities has been the focus of much investigation, very little is known concerning the emergence of comprehension for symbolic relations among actions modeled with toy replicas and their real counterparts. We used videotaped depictions of real actions in a preferential looking task to assess toddlers' ability to comprehend such connections for action categories aligned with familiar object concepts. Across two experiments, 16- and 18-month-olds provided no evidence of understanding such relations, even when action categories were highlighted with verbal prompts. Among 24- and 26-month-olds, comprehension of relations between certain actions modeled with toys and videos of their real-world counterparts began to emerge, independent of expressive vocabulary size. Implications of our results for theoretical conclusions drawn from use of the generalized imitation procedure to study early conceptual development are discussed.     

Understanding the experimenter's intention improves 16-month-olds’ observational learning of the use of a novel tool

Our aim was to investigate why 16-month-old infants fail to master a novel tool-use action via observational learning. We hypothesized that 16-month-olds’ difficulties may be due to not understanding the goal of the observed action. To test this hypothesis, we investigated whether showing infants an explicit demonstration of the goal of the action before demonstrating the action would improve observational learning compared with a classic demonstration of the target action. We examined 16-month-old infants who observed a tool-use action consisting of grasping a rake-like tool to retrieve an out-of-reach toy, under five conditions. Only when infants were shown the goal of the action before demonstration did they show some success.