Imitation of hierarchical action structure by young children

To provide the first systematic test of whether young children will spontaneously perceive and imitate hierarchical structure in complex actions, a task was devised in which a set of 16 elements can be modelled through either of two different, hierarchically organized strategies. Three-year-old children showed a strong and significant tendency to copy whichever of the two hierarchical approaches they witnessed an adult perform. Responses to an element absent in demonstrations, but present at test, showed that children did not merely copy the chain of events they had witnessed, but acquired hierarchically structured rules to which the new element was assimilated. Consistent with this finding, children did not copy specific sequences of actions at lower hierarchical levels.     

Children's Representation and Imitation of Events: How Goal Organization Influences 3‐Year‐Old Children's Memory for Action Sequences

Children's imitation of adults plays a prominent role in human cognitive development. However, few studies have investigated how children represent the complex structure of observed actions which underlies their imitation. We integrate theories of action segmentation, memory, and imitation to investigate whether children's event representation is organized according to veridical serial order or a higher level goal structure. Children were randomly assigned to learn novel event sequences either through interactive hands‐on experience (Study 1) or via storybook (Study 2). Results demonstrate that children's representation of observed actions is organized according to higher level goals, even at the cost of representing the veridical temporal ordering of the sequence. We argue that prioritizing goal structure enhances event memory, and that this mental organization is a key mechanism of social‐cognitive development in real‐world, dynamic environments. It supports cultural learning and imitation in ecologically valid settings when social agents are multitasking and not demonstrating one isolated goal at a time.     

Development of hierarchical conceptual relationships in children's semantic memories

The present study was designed to determine when children first display evidence of hierarchical conceptual organization. Children aged 5 to 9 answered either semantic or sensory questions about a list of words composed of either superordinate terms, prototypical category instance, or moderately typical instances. In a later unanticipated cued recall task the children were given taxonomically related cues composed of the two remaining word types not used in the orienting phase. The 5-year-olds' performance revealed that they possessed a modest degree of hierarchically organized conceptual information, which by age 9 had developed to relatively sophisticated levels. In particular, it was found that the range of information contained in the 5-year-olds' conceptual hierarchies was considerably narrower than that of the 9-year-olds', which supports Rosch's contention that conceptual categories are first constructed around prototypical instances. The children's performance on the cued recall task was also compared to their performance on traditional class inclusion and object-sorting tasks. It was found that the object-sorting task overestimated, while the class inclusion task underestimated the extent to which conceptual information is hierarchically organized in 5-year-olds.     

The role of cuing and organization in children's memory for events

Children's memory for a standardized, hierarchically organized event, making clay, was tested in two experiments. Immediately after participating in this event and again 2 weeks later, children described how they had made the clay. In Experiment 1, action and object cues were presented but only action cues greatly facilitated recall. Children who remade the clay reported more information and also reported more of the actions most central to the goal of the event during delayed recall. In Experiment 2, verbal cues representing two levels in the event hierarchy were presented, but neither aided recall. These and other patterns in the data indicated that, at most, the rudiments of a hierarchical structure had emerged after a single experience. These results were discussed in terms of their implications for the development and organization of event memories.     

Children’s coding of human action: cognitive factors influencing imitaation in 3‐year‐old

We used imitation as a tool for investigating how young children code action. The study was designed to examine the errors children make in re‐enacting manual gestures they see. Thirty‐two 3‐year‐old children served as subjects. Each child was shown 24 gestures, generated by systematically crossing four factors: visual monitoring, spatial endpoint, movement path, and number of hands. The results showed no difference as a function of whether the children could visually monitor their own responses. Interestingly, children made significantly more errors when the adult's action terminated on a body part than they did when the same movement terminated near the body part. There were also significantly more errors when the demonstrated act involved crossing midline than when it did not, and more errors when it involved one hand rather than two hands. Our hypothesis is that human acts are coded in terms of goals. The goals are hierarchically organized, and because young children have difficulty simultaneously integrating multiple goals into one act they often re‐enact the goals that are ranked higher, which leads to the errors observed. We argue that imitation is an active reconstruction of perceived events and taps cognitive processing. We suggest that the goal‐based imitation in 3‐year‐olds is a natural developmental outgrowth of the perceptual–motor mapping and goal‐directed coding of human acts found in infancy.     

Developmental changes in the processing of hierarchical shapes continue into adolescence

The present study was designed to trace the normal development of local and global processing of hierarchical visual forms. We presented pairs of hierarchical shapes to children and adults and asked them to indicate whether the two shapes were the same or different at either the global or the local level. In Experiments 1 (6-year-olds, 10-year-olds, adults) and 2 (10-year-olds, 14-year-olds, adults), we presented stimuli centrally. All age groups responded faster on global trials than local trials (global precedence effect), but the bias was stronger in children and diminished to the adult level between 10 and 14 years of age. In Experiment 3 (10-year-olds, 14-year-olds, adults), we presented stimuli in the left or right visual field so that they were transmitted first to the contralateral hemisphere. All age groups responded faster on local trials when stimuli were presented in the right visual field (left hemisphere); reaction times on global trials were independent of visual field. The results of Experiment 3 suggest that by 10 years of age the hemispheres have adult-like specialization for the processing of hierarchical shapes, at least when attention is directed to the global versus local level. Nevertheless, their greater bias in Experiments 1 and 2 suggests that 10-year-olds are less able than adults to modulate attention to the output from local versus global channels-perhaps because they are less able to ignore distractors and perhaps because the cerebral hemispheres are less able to engage in parallel processing.     

Domains and facets: hierarchical personality assessment using the revised NEO personality inventory

Personality traits are organized hierarchically, with narrow, specific traits combining to define broad, global factors. The Revised NEO Personality Inventory (NEO-PI-R; Costa & McCrae, 1992c) assesses personality at both levels, with six specific facet scales in each of five broad domains. This article describes conceptual issues in specifying facets of a domain and reports evidence on the validity of NEO-PI-R facet scales. Facet analysis-the interpretation of a scale in terms of the specific facets with which it correlates-is illustrated using alternative measures of the five-factor model and occupational scales. Finally, the hierarchical interpretation of personality profiles is discussed. Interpretation on the domain level yields a rapid understanding of the individual interpretation of specific facet scales gives a more detailed assessment.     

The processing of structured and unstructured tonal sequences

The recall of hierarchically organized tonal sequences was investigated in two experiments. An adaptation of the technique of melodic dictation was employed, in which musically trained listeners notated each sequence after it was presented. Strong effects of sequence structure were obtained. Sequences whose tonal structure could be parsimoniously encoded in hierarchical fashion were recalled with a high level of accuracy. Sequences that could not be parsimoniously encoded produced substantially more errors in recall. Temporal segmentation was found to have a substantial effect on performance, which reflected grouping by temporal proximity regardless of tonal structure. The results provide evidence for the hypothesis that we encode tonal materials by inferring sequence structures and alphabets at different hierarchical levels, together with their rules of combination.     

A set-theoretical approach to the problem of hierarchical clustering

A set-theoretical formalization is developed for the problem of generating hierarchically organized collections of subsets, or to use a phrase common in the applied substantive literature, for the problem of hierarchical clustering. A number of terms are introduced to characterize those clustering methods that attempt to limit the size of the overlap between each pair of subsets constructed at a specific “compactness” level. Several examples, motivated primarily by graph theory, are discussed briefly to illustrate the various set-theoretical concepts presented.     

Using a bad tool with good intention: young children's imitation of adults' questionable choices

We present three studies exploring 2- to 4-year-olds’ imitation on witnessing a model whose questionable tool use choices suggested her untrustworthiness. In Study 1, children observed the model accidentally select a physically optimal tool for a task and then intentionally reject it for one that was functionally nonaffordant. When asked to perform the task for her, children at all ages ignored the model’s intentional cues and selected the optimal tool. Study 2 found that when the model’s nonaffordant tool choice was emphasized by claims about its design, 3-year-olds increased imitation. They also imitated, as did 2-year-olds, when the model selected a suboptimal rather than nonaffordant tool. The 4-year-olds consistently avoided imitation. Study 3 replicated these findings with new tools and participants. Additional measures indicated that knowledge about artifact design predicted children’s tendency to ignore the model. These results shed light on developmental trends in the social and cognitive functions of imitation.     

Effects of Knowledge Organization on Task Performance

This study proposes a knowledge organization facilitating human performance on scientifically relevant recall and problem-solving tasks. This organization is structured hierarchically so as to describe knowledge at different levels of detail; it is also task-adapted so that higher levels include information most important for implementing the intended tasks. The efficacy of this organization was assessed by two experiments, in experiment I, college-level subjects read a text and performed special training tasks to acquire knowledge of a physics topic organized either in the preceding hierarchical, or in a detailed single-level .organization; a third group read the single-level organization twice. In a subsequent test, subjects with the hierarchical organization performed appreciably better on tasks of recall, error correction, and knowledge modification. In experiment 2, subjects acquired knowledge in either of two alternative hierarchical organizations of the same physics topic, but with information distributed differently over the levels. As expected, in a subsequent test subjects performed better on those tasks depending on information from higher levels of their hierarchical organization. The specially designed training was effective in producing the desired organization of a subject's internal knowledge, but subjects with lower physics grades seemed less able to assimilate and use a hierarchical organization. Similar conclusions were obtained from a third experiment in which internal, knowledge organization was inferred from an analysis of free-recall protocols.     

Looking good versus doing good: which factors take precedence when children learn about new tools?

We present two experiments exploring whether individuals would be persuaded to imitate the intentional action of an adult model whose actions suggest that the correct way to complete a task is with an inefficient tool. In Experiment 1, children ages 5–10 years and a group of adults watched an adult model reject an efficient tool in favor of one that was inefficient, but claim it was “made for” the task. Results indicated low rates of imitation of the model’s intentional choice until 9 and 10 years of age. In Experiment 2, children ages 3–11 years again watched a model reject a functional tool in favor of a nonfunctional one. This time, the demonstration took place on video. For half of the participants, the model from the video was present to offer a choice between the two tools (high-pressure condition), and for the other half, she was absent (low-pressure condition). Children also completed a social desirability questionnaire to explore relationships between imitation choices and personality. Results indicated that rates of imitation were associated with higher scores on the social desirability scale among children ages 3–7 years. Among 8- to 11-year-olds – and especially among 9- and 10-year-olds – the decision to copy the model’s intentional choice was more likely when the model was present than when she was absent. The findings reveal the contributions of age, personality, and social pressure to differences in imitation.     

What do children with autism attend to during imitation tasks?

Individuals with autism show a complex profile of differences in imitative ability, including a general deficit in precision of imitating another’s actions and special difficulty in imitating nonmeaningful gestures relative to meaningful actions on objects. Given that they also show atypical patterns of visual attention when observing social stimuli, we investigated whether possible differences in visual attention when observing an action to be imitated may contribute to imitative difficulties in autism in both nonmeaningful gestures and meaningful actions on objects. Results indicated that (a) a group of 18 high-functioning 8- to 15-year-olds with autistic disorder, in comparison with a matched group of 13 typically developing children, showed similar patterns of visual attention to the demonstrator’s action but decreased attention to his face when observing a model to be imitated; (b) nonmeaningful gestures and meaningful actions on objects triggered distinct visual attention patterns that did not differ between groups; (c) the autism group demonstrated reduced imitative precision for both types of imitation; and (d) duration of visual attention to the demonstrator’s action was related to imitation precision for nonmeaningful gestures in the autism group.     

Imitation is beneficial for verb learning in toddlers

The interplay between action and language is still not fully understood in terms of its relevance for early language development. Here, we investigated whether action imitation may be beneficial for first language acquisition. In a word-learning study 24-, 30- and 36-month-old children (N = 96) learned the labels of different actions in one of two conditions: Either the children just observed the experimenter producing the action (observation condition) or children produced the action themselves (action condition). The results show that 36-month-olds learned the labels of the more complex actions in both conditions, whereas 30-month-olds learned the labels only in the action but not in the observation condition. These findings suggest that action imitation is beneficial for verb learning early in life.     

Younger apes and human children plan their moves in a maze task

Planning defined as the predetermination of a sequence of actions towards some goal is crucial for complex problem solving. To shed light on the evolution of executive functions, we investigated the ontogenetic and phylogenetic origins of planning. Therefore, we presented all four great apes species (N = 12) as well as 4- and 5-year-old human preschoolers (N = 24) with a vertical maze task. To gain a reward placed on the uppermost level of the maze, subjects had to move the reward to the bottom through open gaps situated at each level of the maze. In total, there were ten gaps located over three of the maze’s levels, and free passage through these gaps could be flexibly blocked using multiple traps. Due to the decision tree design of the maze, the subjects had to plan their actions depending on the trap configuration up to two steps ahead to successfully retrieve the reward. We found that (1) our measure of planning was negatively correlated with age in nonhuman apes, (2) younger apes as well as 5-year-old children planned their moves up to two steps ahead whereas 4-year-olds were limited to plan one step ahead, and (3) similar performance but different underlying limitations between apes and children. Namely, while all species of nonhuman apes were limited by a lack of motor control, human children exhibited a shortage in shifting their attention across a sequence of subgoals.     

Evidence for a distributed hierarchy of action representation in the brain

Complex human behavior is organized around temporally distal outcomes. Behavioral studies based on tasks such as normal prehension, multi-step object use and imitation establish the existence of relative hierarchies of motor control. The retrieval errors in apraxia also support the notion of a hierarchical model for representing action in the brain. In this review, three functional brain imaging studies of action observation using the method of repetition suppression are used to identify a putative neural architecture that supports action understanding at the level of kinematics, object centered goals and ultimately, motor outcomes. These results, based on observation, may match a similar functional-anatomic hierarchy for action planning and execution. If this is true, then the findings support a functional-anatomic model that is distributed across a set of interconnected brain areas that are differentially recruited for different aspects of goal-oriented behavior, rather than a homogeneous mirror neuron system for organizing and understanding all behavior.     

Imitation in toddlers as a function of motor and verbal aspects of modeling

This study investigated the effects of the motor and verbal aspects of modeling on imitation. The subjects were 2- and 3-year-old children (N = 96). The child's imitation responses were recorded during the play period that followed each modeled act. Each child observed the model in one of four modeling conditions. In Condition 1, the model "flew" a telephone while saying that he or she was flying an airplane. Imitation was recorded as motor if the child flew the telephone but was recorded as verbal and realistic if the child flew an airplane. In Condition 2, the model flew an airplane while saying that he or she was flying a telephone. Imitation was recorded as verbal if the child flew the telephone. In Condition 3, the model flew an airplane and said that he or she was flying an airplane. If the child flew an airplane, imitation was scored as motor, verbal, and realistic. In Condition 4, the model flew a telephone and said that he or she was flying a telephone. Imitation was scored as motor and verbal if the child flew the telephone but was scored as realistic if the child flew the airplane. In Condition 1, 2-year-olds displayed more motor imitation than 3-year-olds, and 3-year-olds displayed more verbal-reality imitation than 2-year-olds. Boys displayed more motor imitation than girls. There were no age or sex differences in Condition 2. In Condition 3, 2-year-olds imitated more than 3-year-olds, with 3-year-old girls imitating the least. In Condition 4, reality imitation was largely due to 2-year-old boys' imitation of masculine-type acts.     

Index to Volume 163

This study investigated the effects of the motor and verbal aspects of modeling on imitation. The subjects were 2- and 3-year-old children (N = 96). The child's imitation responses were recorded during the play period that followed each modeled act. Each child observed the model in one of four modeling conditions. In Condition 1, the model “flew” a telephone while saying that he or she was flying an airplane. Imitation was recorded as motor if the child flew the telephone but was recorded as verbal and realistic if the child flew an airplane. In Condition 2, the model flew an airplane while saying that he or she was flying a telephone. Imitation was recorded as verbal if the child flew the telephone. In Condition 3, the model flew an airplane and said that he or she was flying an airplane. If the child flew an airplane, imitation was scored as motor, verbal, and. realistic. In Condition 4, the model flew a telephone and said that he or she was flying a telephone. Imitation was scored as motor and verbal if the child flew the telephone but was scored as realistic if the child flew the airplane. In Condition 1, 2-year-olds displayed more motor imitation than 3-year-olds, and 3-year-olds displayed more verbal-reality imitation than 2-year-olds. Boys displayed more motor imitation than girls. There were no age or sex differences in Condition 2. In Condition 3, 2-year-olds imitated more than 3-year-olds, with 3-year-old girls imitating the least. In Condition 4, reality imitation was largely due to 2-year-old boys' imitation of masculine-type acts.     

Determinants of imitation of hand-to-body gestures in 2- and 3-year-old children

Twenty children, ten 2-year-olds and ten 3-year-olds, participated in an AB procedure. In the baseline phase, each child was trained the same four matching relations to criterion under intermittent reinforcement. During the subsequent imitation test, the experimenter modeled a total of 20 target gestures (six trials each) interspersed with intermittently reinforced baseline trials. In each session, target gestures were selected in a pre-randomized sequence from: Set 1--ear touches; Set 2--shoulder touches; Set 3--midarm touches; and Set 4--wrist touches; subjects' responses to targets were not reinforced. In each target set, half the gestures featured in nursery matching games and were termed common targets whereas the remainder, which were topographically similar but did not feature in the games, served as uncommon targets. The children produced significantly more matching responses to common target models than to uncommon ones. Common responses were also produced as mismatches to uncommon target models more often than vice versa. Response accuracy did not improve over trials, suggesting that "parity" did not serve as a conditioned reinforcer. All children showed a strong bias for "mirroring"--responding in the same hemispace as the modeler. The 2-year-olds produced more matching errors than the 3-year-olds and most children showed a bias for responding with their right hands. The strong effects of training environment (nursery matching games) are consistent with a Skinnerian account, but not a cognitive goal theory account, of imitation in young children.