Imitation of causally opaque versus causally transparent tool use by 3- and 5-year-old children

We investigated whether the tendency to imitate or emulate is influenced by the availability of causal information, and the amount of information available in a display. Three and 5-year-old children were shown by either a live or video model how to obtain a reward from either a clear or an opaque puzzle box. Some of the actions in the sequence were causally relevant to retrieving the reward, whereas others were irrelevant. The clear box made the causally irrelevant actions visible, whereas the opaque box prevented them from being seen. Results indicated that both 3- and 5-year-old children imitated the irrelevant actions regardless of the availability of causal information following a live demonstration. In contrast, the 3-year-olds employed an emulative approach, omitting irrelevant actions, when the information available was degraded in a video demonstration. However, the 5-year-olds were unaffected by the degraded information and employed an imitative approach. We suggest that imitation develops to be such an adaptive human strategy that it may often be employed at the expense of task efficiency.     

Emulation and “overemulation” in the social learning of causally opaque versus causally transparent tool use by 23- and 30-month-olds

We explored whether a rising trend to blindly “overcopy” a model’s causally irrelevant actions between 3 and 5 years of age, found in previous studies, predicts a more circumspect disposition in much younger children. Children between 23 and 30 months of age observed a model use a tool to retrieve a reward from either a transparent or opaque puzzle box. Some of the tool actions were irrelevant to reward retrieval, whereas others were causally necessary. The causal relevance of the tool actions was highly visible in the transparent box condition, allowing the participants to potentially discriminate which actions were necessary. In contrast, the causal efficacy of the tool was hidden in the opaque box condition. When both the 23- and 30-month-olds were presented with either the transparent or opaque box, they were most commonly emulative rather than imitative, performing only the causally necessary actions. This strategy contrasts with the blanket imitation of both causally irrelevant and causally relevant actions witnessed at 3 and 5 years of age in our previous studies. The results challenge a current view of 1- and 2-year-olds as largely “blind imitators”; instead, they show that these young children have a variety of social learning processes available to them. More broadly the emerging patterns of results suggest, rather counterintuitively, that the human species becomes more imitative rather than less imitative with age, in some ways “mindlessly” so.     

Choosing and using tools: Prior experience and task difficulty influence preschoolers’ tool-use strategies

Children's acquisition of tool use abilities is an important part of development but is not yet well understood. This study compares two modes of tool-use learning, observation and individual haptic experience. Two- and 3-year-olds had haptic experience with tools, observed tool use by others, had both haptic and observational experience, or no tool exposure. Their tool choice and use were evaluated across six problem-solving tasks that varied in degree of difficulty. Children learned about tools better by observation than by individual learning through manual exploration. Performance also varied by task difficulty, with more complex tasks proving more difficult. Findings are discussed from cognitive and evolutionary perspectives.     

Cultural transmission of irrelevant tool actions in diffusion chains of 3- and 5-year-old children

We used the diffusion chain method in order to investigate whether irrelevant actions would be transmitted along chains of 3- and 5-year-old children. Four chains of eight children witnessed a trained “expert” child perform a sequence of actions in order to retrieve a reward from either a transparent or an opaque puzzle box. The action sequence involved both goal relevant and goal irrelevant actions. In the transparent box chains the participants could potentially determine which of the actions were irrelevant as the causal effects were clearly visible. Results indicated that irrelevant actions transmitted down chains of 3-year-old children irrespective of box transparency. In contrast, irrelevant actions dropped out of the transparent box chain extremely quickly at 5 years, but were maintained within the opaque chain. These findings highlight the power of the diffusion chain method as a tool for exploring cultural learning.     

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.     

Imitation: definitions, evidence, and mechanisms

Imitation can be defined as the copying of behavior. To a biologist, interest in imitation is focused on its adaptive value for the survival of the organism, but to a psychologist, the mechanisms responsible for imitation are the most interesting. For psychologists, the most important cases of imitation are those that involve demonstrated behavior that the imitator cannot see when it performs the behavior (e.g., scratching one's head). Such examples of imitation are sometimes referred to as opaque imitation because they are difficult to account for without positing cognitive mechanisms, such as perspective taking, that most animals have not been acknowledged to have. The present review first identifies various forms of social influence and social learning that do not qualify as opaque imitation, including species-typical mechanisms (e.g., mimicry and contagion), motivational mechanisms (e.g., social facilitation, incentive motivation, transfer of fear), attentional mechanisms (e.g., local enhancement, stimulus enhancement), imprinting, following, observational conditioning, and learning how the environment works (affordance learning). It then presents evidence for different forms of opaque imitation in animals, and identifies characteristics of human imitation that have been proposed to distinguish it from animal imitation. Finally, it examines the role played in opaque imitation by demonstrator reinforcement and observer motivation. Although accounts of imitation have been proposed that vary in their level of analysis from neural to cognitive, at present no theory of imitation appears to be adequate to account for the varied results that have been found.     

Own and Others' Prior Experiences Influence Children's Imitation of Causal Acts

Young children learn from others' examples, and they do so selectively. We examine whether the efficacy of prior experiences influences children's imitation. Thirty-six-month-olds had initial experience on a causal learning task either by performing the task themselves or by watching an adult perform it. The nature of the experience was manipulated such that the actor had either an easy or a difficult experience completing the task. Next, a second adult demonstrated an innovative technique for completing it. Children who had a difficult first-person experience, and those who had witnessed another person having difficulty, were significantly more likely to adopt and imitate the adult's innovation than those who had or witnessed an easy experience. Children who observed another were also more likely to imitate than were those who had the initial experience themselves. Imitation is influenced by prior experience, both when it is obtained through one's own hands-on motor manipulation and when it derives from observing the acts of others.     

Observational learning from tool using models by human-reared and mother-reared capuchin monkeys (<Emphasis Type="Italic">Cebus apella</Emphasis>)

Studies of wild capuchins suggest an important role for social learning, but experiments with captive subjects have generally not supported this. Here we report social learning in two quite different populations of capuchin monkeys (Cebus apella). In experiment 1, human-raised monkeys observed a familiar human model open a foraging box using a tool in one of two alternative ways: levering versus poking. In experiment 2, mother-raised monkeys viewed similar techniques demonstrated by monkey models. A control group in each population saw no model. In both experiments, independent coders detected which technique experimental subjects had seen, thus confirming social learning. Further analyses examined fidelity of copying at three levels of resolution. The human-raised monkeys exhibited fidelity at the highest level, the specific tool use technique witnessed. The lever technique was seen only in monkeys exposed to a levering model, by contrast with controls and those witnessing poke. Mother-reared monkeys instead typically ignored the tool and exhibited fidelity at a lower level, tending only to re-create whichever result the model had achieved by either levering or poking. Nevertheless this level of social learning was associated with significantly greater levels of success in monkeys witnessing a model than in controls, an effect absent in the human-reared population. Results in both populations are consistent with a process of canalization of the repertoire in the direction of the approach witnessed, producing a narrower, socially shaped behavioural profile than among controls who saw no model. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Regulation of emotion and behavior among 3- and 5-year-olds

In this cross-sectional study, the authors examined the relationship between emotion and behavior regulation in 3- and 5-year olds. Eighty-seven children performed a compliance sorting task. The authors manipulated the demand for emotion regulation by presenting and then hiding toys (low) or making toys visible (high). Mothers and teachers rated children's coping responses. Five-year-olds sorted less in the high condition than in the low condition, and 3-year-olds spent equal time sorting in both conditions. Compliance was positively correlated with problem-focused coping and negatively correlated with emotion-focused coping. Correlations between emotion and behavior regulation were stronger for the 5-year-olds. Age groups were differently affected by the higher demands of emotion regulation, indicating that the child's resources for regulation interact with the task demands to determine behavioral outcome.     

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.     

Observational learning of tool use in children: Investigating cultural spread through diffusion chains and learning mechanisms through ghost displays

In the first of two experiments, we demonstrate the spread of a novel form of tool use across 20 “cultural generations” of child-to-child transmission. An experimentally seeded technique spread with 100% fidelity along twice as many “generations” as has been investigated in recent exploratory “diffusion” experiments of this type. This contrasted with only a single child discovering the technique spontaneously in a comparable group tested individually without any model. This study accordingly documents children’s social learning of tool use on a new, population-level scale that characterizes real-world cultural phenomena. In a second experiment, underlying social learning processes were investigated with a focus on the contrast between imitation (defined as copying actions) and emulation (defined as learning from the results of actions only). In two different “ghost” conditions, children were presented with the task used in the first experiment but now operated without sight of an agent performing the task, thereby presenting only the information used in emulation. Children in ghost conditions were less successful than those who had watched a model in action and showed variable matching to what they had seen. These findings suggest the importance of observational learning of complex tool use through imitation rather than only through emulation. Results of the two experiments are compared with those of similar experiments conducted previously with chimpanzees and are discussed in relation to the wider perspective of human culture and the influence of task complexity on social learning.     

Copying results and copying actions in the process of social learning: chimpanzees (Pan troglodytes) and human children (Homo sapiens)

There is currently much debate about the nature of social learning in chimpanzees. The main question is whether they can copy others' actions, as opposed to reproducing the environmental effects of these actions using their own preexisting behavioral strategies. In the current study, chimpanzees (Pan troglodytes) and human children (Homo sapiens) were shown different demonstrations of how to open a tube-in both cases by a conspecific. In different experimental conditions, demonstrations consisted of (1) action only (the actions necessary to open the tube without actually opening it); (2) end state only (the open tube, without showing any actions); (3) both of these components (in a full demonstration); or (4) neither of these components (in a baseline condition). In the first three conditions subjects saw one of two different ways that the tube could open (break in middle; caps off ends). Subjects' behavior in each condition was assessed for how often they opened the tube, how often they opened it in the same location as the demonstrator, and how often they copied the demonstrator's actions or style of opening the tube. Whereas chimpanzees reproduced mainly the environmental results of the demonstrations (emulation), human children often reproduced the demonstrator's actions (imitation). Because the procedure used was similar in many ways to the procedure that Meltzoff (Dev Psych 31:1, 1995) used to study the understanding of others' unfulfilled intentions, the implications of these findings with regard to chimpanzees' understanding of others' intentions are also discussed.     

Phonological similarity and mutual exclusivity: on-line recognition of atypical pronunciations in 3-5-year-olds

Recent research has considered the phonological specificity of children's word representations, but few studies have examined the flexibility of those representations. Tolerating acoustic-phonetic deviations has been viewed as a negative in terms of discriminating minimally different word forms, but may be a positive in an increasingly multicultural society where children encounter speakers with variable accents. To explore children's on-line processing of accented speech, preschoolers heard atypically pronounced words (e. g. 'fesh', from fish) and selected pictures from a four-item display as eye movements were tracked. Children recognized similarity between typical and accented variants, selecting the fish overwhelmingly when hearing 'fesh' (Experiment 1), even when a novel-picture alternative was present (Experiment 2). However, eye movements indicated slowed on-line recognition of accented relative to typical variants. Novel-picture selections increased with feature distance from familiar forms, but were similarly sensitive to vowel, onset, and coda changes (Experiment 3). Implications for child accent processing and mutual exclusivity are discussed.     

Syntactic structure and artificial grammar learning: the learnability of embedded hierarchical structures

Embedded hierarchical structures, such as "the rat the cat ate was brown", constitute a core generative property of a natural language theory. Several recent studies have reported learning of hierarchical embeddings in artificial grammar learning (AGL) tasks, and described the functional specificity of Broca's area for processing such structures. In two experiments, we investigated whether alternative strategies can explain the learning success in these studies. We trained participants on hierarchical sequences, and found no evidence for the learning of hierarchical embeddings in test situations identical to those from other studies in the literature. Instead, participants appeared to solve the task by exploiting surface distinctions between legal and illegal sequences, and applying strategies such as counting or repetition detection. We suggest alternative interpretations for the observed activation of Broca's area, in terms of the application of calculation rules or of a differential role of working memory. We claim that the learnability of hierarchical embeddings in AGL tasks remains to be demonstrated.     

Children's imitation of causal action sequences is influenced by statistical and pedagogical evidence

Children are ubiquitous imitators, but how do they decide which actions to imitate? One possibility is that children rationally combine multiple sources of information about which actions are necessary to cause a particular outcome. For instance, children might learn from contingencies between action sequences and outcomes across repeated demonstrations, and they might also use information about the actor’s knowledge state and pedagogical intentions. We define a Bayesian model that predicts children will decide whether to imitate part or all of an action sequence based on both the pattern of statistical evidence and the demonstrator’s pedagogical stance. To test this prediction, we conducted an experiment in which preschool children watched an experimenter repeatedly perform sequences of varying actions followed by an outcome. Children’s imitation of sequences that produced the outcome increased, in some cases resulting in production of shorter sequences of actions that the children had never seen performed in isolation. A second experiment established that children interpret the same statistical evidence differently when it comes from a knowledgeable teacher versus a naïve demonstrator. In particular, in the pedagogical case children are more likely to “overimitate” by reproducing the entire demonstrated sequence. This behavior is consistent with our model’s predictions, and suggests that children attend to both statistical and pedagogical evidence in deciding which actions to imitate, rather than obligately imitating successful action sequences.     

Developmental change in the acuity of the "Number Sense": The Approximate Number System in 3-, 4-, 5-, and 6-year-olds and adults

Behavioral, neuropsychological, and brain imaging research points to a dedicated system for processing number that is shared across development and across species. This foundational Approximate Number System (ANS) operates over multiple modalities, forming representations of the number of objects, sounds, or events in a scene. This system is imprecise and hence differs from exact counting. Evidence suggests that the resolution of the ANS, as specified by a Weber fraction, increases with age such that adults can discriminate numerosities that infants cannot. However, the Weber fraction has yet to be determined for participants of any age between 9 months and adulthood, leaving its developmental trajectory unclear. Here we identify the Weber fraction of the ANS in 3-, 4-, 5-, and 6-year-old children and in adults. We show that the resolution of this system continues to increase throughout childhood, with adultlike levels of acuity attained surprisingly late in development.     

Empathy, theory of mind, and individual differences in the appropriation bias among 4- and 5-year-olds

Evidence that young children often claim ownership of their partner’s contributions to an earlier collaborative activity, the appropriation bias, has been attributed to shared intentionality (Cognitive Development (1998) 13, 91–108). The current investigation explored this notion by examining individual differences in the bias among 4- and 5-year-olds as a function of empathy and theory of mind. On two occasions, children joined an adult and two dolls (with each doll being operated by one of the humans) in a picture matching board game before being asked to remember who placed each picture. Children showed a robust appropriation bias despite excellent recognition memory for the studied pictures (Study 1) and particularly in relation to the human sources (Study 2). Whereas higher levels of self-reported empathy were associated with a greater frequency of appropriation errors and fewer correct attributions for pictures placed by the adult and her doll partner, the opposite pattern emerged for theory of mind. Moreover, the positive relations between theory of mind and source monitoring accuracy remained robust after controlling for general ability and inhibitory skills. We consider the implications of these findings for understanding the processes driving the appropriation bias.     

Use of context in question answering by 3-, 4- and 5-year-old children

This study investigates, within the theory of relevance of Sperber & Wilson (1995), how 3-, 4-, and 5-year-old children (n = 45) use context when answering questions. The children were required to answer questions that placed differing contextual and processing demands on them, as predicted by the theory. The results indicate that an increasing ability to use complex contextual information was related to age and was reflected in the children's ability to answer questions appropriately. A developmental pattern became evident in terms of how the children assigned referents, enriched semantic underdetermination, and recovered implicatures. It also became evident that even at the age of 5 years 6 months the children were in the process of becoming more skilled at integrating contextually complex inferences. It was further shown how children's selection of the appropriate context, given the focus of the question, depended on how relevance was achieved in that context.     

The relation between language and cognition in 3- to 9-year-olds: the acquisition of grammatical gender in French

The French language has a grammatical gender system in which all nouns are assigned either a masculine or a feminine gender. Nouns provide two types of gender cues that can potentially guide gender attribution: morphophonological cues carried by endings and semantic cues (natural gender). The first goal of this study was to describe the acquisition of the probabilistic system based on phonological oppositions on word endings by French-speaking children. The second goal was to explore the extent to which this system affects categorization. In the study, 3- to 9-year-olds assigned gender categorization to invented nouns whose endings were typically masculine, typically feminine, or neutral. Two response conditions were used. In the determiner condition, children indicated the gender class by orally providing the determiner un or une marked for gender. In the picture condition, responses were given by pointing to the picture of a Martian-like female or male person that would be best called by each spoken pseudoword. Results indicated that as young as 3 years, children associated the determiner corresponding to the ending bias at greater than chance levels. Ending-consistent performance increased from 3 to 9 years of age. Moreover, from 4 years of age onward, sensitivity to endings affected categorization. Starting at that age, pictures were selected according to endings at greater than chance levels. This effect also increased with age. The discussion deals with the mechanisms of language acquisition and the relation between language and cognition.