Imitation and interindividual differences: Belief in free will is not related to automatic imitation

It is well known that individuals have the tendency to automatically imitate each other and that such imitative behavior is fostered by perceiving intentions in others’ actions. That is, past research has shown that perceiving an action as internally driven enhances the shared representation of observed and executed actions increasing automatic imitation. An interpersonal factor that increases the perception that a behavior is internally driven is belief in free will. Consequently, we hypothesized that the more individuals believe in free will, the more they automatically imitate others. To test this prediction, we conducted two high-powered (total N = 642) and preregistered studies in which we assessed automatic imitation with the imitation-inhibition task. Contrary to our predictions, belief in free will did not correlate with automatic imitation. This finding contributes to current findings challenging the assumption that automatic imitation is modulated by interindividual differences. Further theoretical implications are discussed.

Top-Down Modulation of Motor Priming by Belief About Animacy: A Registered Replication Report

Research has shown that people automatically imitate others and that this tendency is stronger when the other person is a human compared with a non-human agent. However, a controversial question is whether automatic imitation is also modulated by whether people believe the other person is a human. Although early research supported this hypothesis, not all studies reached the same conclusion and a recent meta-analysis found that there is currently neither evidence in favor nor against an influence of animacy beliefs on automatic imitation. One of the most prominent studies supporting such an influence is the study by Liepelt & Brass (2010), who found that automatic imitation was stronger when participants believed an ambiguous, gloved hand to be human, as opposed to wooden. In this registered report, including both original authors, we provide a high-powered replication of this study. By doing so, the current report contributes to answering the longstanding question of whether automatic imitation can be modulated by high-level social beliefs.

Similarity and automatic imitation

Individuals automatically imitate a wide range of different behaviors. Previous research suggests that imitation as a social process depends on the similarity between interaction partners. However, some of the experiments supporting this notion could not be replicated and all of the supporting experiments manipulated not only similarity between actor and observer, but also other features. Thus, the existing evidence leaves open whether similarity as such moderates automatic imitation. To directly test the similarity account, in four experiments, we manipulated participants’ focus on similarities or differences while holding the stimulus material constant. In Experiment 1, we presented participants with a hand and let them either focus on similarities, differences, or neutral aspects between their own hand and the other person’s hand. The results indicate that focusing on similarities increased perceived similarity between the own and the other person’s hand. In Experiments 2 to 4, we tested the hypothesis that focusing on similarities, as compared with differences, increases automatic imitation. Experiment 2 tested the basic effect and found support for our prediction. Experiment 3 and 4 replicated this finding with higher-powered samples. Exploratory investigations further suggest that it is a focus on differences that decreases automatic imitation, and not a focus on similarities that increases automatic imitation. Theoretical implications and future directions are discussed.

Concurrently observed actions are represented as independent actions and not as a compound action

Recent research suggests that we can simultaneously represent the actions of multiple agents in our motor system. However, it is currently unclear exactly how we represent their actions. Here, we tested two competing hypotheses. According to the independence hypothesis, we represent concurrently observed actions as independent, competing actions. According to the compound hypothesis, we instead integrate those actions, whenever possible, into compound actions. In Experiment 1 (N = 32), we first show that the standard imitation-inhibition task with a single hand can be extended to measure automatic imitation of compound actions. In Experiment 2 (N = 55), we then tested how we represent concurrently observed actions by further extending this task to include two hands performing identical or different actions. The results revealed that two hands performing two different actions (e.g., one hand lifts index finger, one hand lifts middle finger) produced an effect similar to that of both hands performing just one of those actions (e.g., both hands lift index finger) but different from that of both hands performing both actions together (e.g., lift both index and middle finger). As such, our results show that concurrently observed actions are coded separately in the motor system.