An integrative model of rational imitation in infancy

Infants' selective imitation of a transitive agent and an intransitive agent

This study examined how the reliability (i.e., transitivity) of an agent's object choices affects 16-month-old infants' (N = 48) imitation of her unconventional way of turning on a touch light box with her head when her hands were available. When the agent made transitive choices (i.e., she chose Object A over Object B, Object B over Object C, and then A over C), infants imitated her head touch actions. When the agent made intransitive choices (i.e., after choosing A over B and B over C, she chose C over A), infants were more likely to use only their hands to touch the light box. In addition, when it was presumably difficult for infants to judge the transitivity of the agent's choices (i.e., she chose B over C, A over B, and then A over C), they used their hands more. These results demonstrate that infants' understanding informs their decisions to selectively imitate others' specific ways to act on novel artifacts, consistent with young children's selective trust in information provided by other people based on their epistemic reliability.

Rational imitation declines within the second year of life: Changes in the function of imitation

Cultural learning plays a crucial role in enabling children to fit into their social community by mastering culture-specific habits. Infants learn actions via imitation, and they seem to be sensitive to the context in which a model demonstrates these. They imitate rationally by copying unusual means to achieve a goal more when the model chooses this means voluntarily compared with when some constraints force the model to do so. We investigated the development of rational imitation. In a within-participants design, 18-, 24-, and 36-month-olds (N = 293) observed two unusual actions: Instead of using her hands, a model operated an apparatus by using her head or by sitting on the apparatus. The model did so once with her hands being occupied and once with her hands being free. Besides measuring participants' imitative responses, we analyzed the gaze behavior directed at the model during the response phase of the current study and of 14-month-olds (N = 82) from Gellén and Buttelmann's study (Child Development Research, Vol. 2017, art. 8080649 [2017]). Increasing age was accompanied by an increasing rate of overall imitation across conditions. None of the three older age groups selectively imitated the unusual actions significantly more often in the hands-free condition than in the hands-occupied condition. Thus, rational imitation seems to disappear during the second year of life. Furthermore, there was a significant increase between 14 and 24 months of age and beyond in children's tendency to gaze at the model after reenacting the observed action. Children's gaze behavior indicates that this pattern might be due to a growing underlying social component in early cultural learning.

Thirteen- to Sixteen-Months Old Infants Are Able to Imitate a Novel Act from Memory in Both Unfamiliar and Familiar Settings But Do Not Show Evidence of Rational Inferential Processes

Gergely et al. (2002) reported that children imitated a novel action - illuminating a light-box by using the forehead - after a delay significantly more often if the hands of the experimenter had been visible in comparison with if they had been covered. In an attempt to explore these findings we conducted two studies with a total N of 63 children. Both studies investigated deferred imitation of the action in two conditions, with the hands of the experimenter visible or covered, but the settings differed. Study 1 (n = 30; mean age = 16.6 months) was carried out in an unfamiliar environment (a laboratory setting) while Study 2 (n = 33; mean age = 13.3 months) was conducted in familiar surroundings (at home or at day care). The results showed that 50% of the children in Study 1 and 42.4% in Study 2 evidenced deferred imitation as compared to only 4.9% (n = 2) in the baseline condition. However, in none of the studies did the children use inferential processes when imitating, we detected no significant differences between the two conditions, hands visible or hands covered. The findings add to the validity of the head touch procedure as a measure of declarative-like memory processes in the pre-verbal child. At the same time the findings question the robustness of the concept 'rational imitation,' it seems not as easy as expected to elicit a response based on rational inferential processes in this age group.

Fourteen-Month-Olds Adapt Their Imitative Behavior in Light of a Model’s Constraints

Rather than reenacting every action they observe, preverbal infants adapt their imitative behavior. Although previous studies have revealed the capability of preverbal infants to imitate selectively, the question about the adaptability of this behavior on an individual level did not attract considerable scientific attention until now. In the current study, we investigated whether 14-month-old infants flexibly alternate their imitative response in accordance with a model’s changing physical constraints in a body-part imitation paradigm. Participants were presented with two novel actions whereby a model illuminated a light-box and turned on a sound-box, either by using her forehead (head touch) or by sitting on the apparatus (sit-touch). Each participant observed these tasks in two conditions: once where the model’s hands were occupied and once where her hands were free while executing the head or sit-touch. Participants were more likely to reenact the observed novel behavior when the model had freely chosen to perform it than when she had to do so due to physical constraints. Not only did we replicate a number of previous findings, we show here that preverbal infants adapt their imitative behavior across conditions based on the physical constraints of the model. These results point towards the adaptable nature of imitative behavior also on an individual level. This ability might be one of the building blocks for children for learning their social group’s specific action repertoire.

The relation between contingency preference and imitation in 6–8-month-old infants

Detecting self-generated actions and imitating other-generated actions are important abilities in order to interact with others. The relationship between these domains was investigated in 6–8-month-old infants. In a contingency-preference task, infants observed their own legs on a real-time and a delayed video display. In an imitation task, the experimenter demonstrated a three-step action directed at a puppet mouse. The Cognitive Scale of the Bayley Scales of Infant and Toddler Development was administered in order to control for the infants’ cognitive developmental status. A negative correlation was found between the proportion of time spent looking at the delayed display in the contingency-preference task and the imitation score in the imitation task. This indicates that the lower the infants’ preference for the delayed video image, the more likely they were to imitate. The correlation between contingency preference and imitation remained even after controlling for cognitive developmental status. Thus, a basic interest in high contingency might underlie the preference for observing self-generated actions and imitating other-generated actions.