Social attitudes differentially modulate imitation in adolescents and adults

Spike-timing-dependent plasticity induction reveals dissociable supplementary- and premotor-motor pathways to automatic imitation

Humans tend to spontaneously imitate others' behavior, even when detrimental to the task at hand. The action observation network (AON) is consistently recruited during imitative tasks. However, whether automatic imitation is mediated by cortico-cortical projections from AON regions to the primary motor cortex (M1) remains speculative. Similarly, the potentially dissociable role of AON-to-M1 pathways involving the ventral premotor cortex (PMv) or supplementary motor area (SMA) in automatic imitation is unclear. Here, we used cortico-cortical paired associative stimulation (ccPAS) to enhance or hinder effective connectivity in PMv-to-M1 and SMA-to-M1 pathways via Hebbian spike-timing-dependent plasticity (STDP) to test their functional relevance to automatic and voluntary motor imitation. ccPAS affected behavior under competition between task rules and prepotent visuomotor associations underpinning automatic imitation. Critically, we found dissociable effects of manipulating the strength of the two pathways. While strengthening PMv-to-M1 projections enhanced automatic imitation, weakening them hindered it. On the other hand, strengthening SMA-to-M1 projections reduced automatic imitation but also reduced interference from task-irrelevant cues during voluntary imitation. Our study demonstrates that driving Hebbian STDP in AON-to-M1 projections induces opposite effects on automatic imitation that depend on the targeted pathway. Our results provide direct causal evidence of the functional role of PMv-to-M1 projections for automatic imitation, seemingly involved in spontaneously mirroring observed actions and facilitating the tendency to imitate them. Moreover, our findings support the notion that SMA exerts an opposite gating function, controlling M1 to prevent overt motor behavior when inadequate to the context.

Driving Hebbian plasticity over ventral premotor-motor projections transiently enhances motor resonance

BACKGROUND

Making sense of others' actions relies on the activation of an action observation network (AON), which maps visual information about observed actions onto the observer's motor system. This motor resonance process manifests in the primary motor cortex (M1) as increased corticospinal excitability finely tuned to the muscles engaged in the observed action. Motor resonance in M1 is facilitated by projections from higher-order AON regions. However, whether manipulating the strength of AON-to-M1 connectivity affects motor resonance remains unclear.

METHODS

We used transcranial magnetic stimulation (TMS) in 48 healthy humans. Cortico-cortical paired associative stimulation (ccPAS) was administered over M1 and the ventral premotor cortex (PMv), a key AON node, to induce spike-timing-dependent plasticity (STDP) in the pathway connecting them. Single-pulse TMS assessed motor resonance during action observation.

RESULTS

Before ccPAS, action observation increased corticospinal excitability in the muscles corresponding to the observed movements, reflecting motor resonance in M1. Notably, ccPAS aimed at strengthening projections from PMv to M1 (PMv→M1) induced short-term enhancement of motor resonance. The enhancement specifically occurred with the ccPAS configuration consistent with forward PMv→M1 projections and dissipated 20 min post-stimulation; ccPAS administered in the reverse order (M1→PMv) and sham stimulation did not affect motor resonance.

CONCLUSIONS

These findings provide the first evidence that inducing STDP to strengthen PMv input to M1 neurons causally enhances muscle-specific motor resonance in M1. Our study sheds light on the plastic mechanisms that shape AON functionality and demonstrates that exogenous manipulation of AON connectivity can influence basic mirror mechanisms that underlie social perception.

The effect of automatic imitation in serial movements with different effectors

Individuals often imitate the postures or gestures of others in everyday life, without even being aware. This behavioral tendency is known as "automatic imitation" in laboratory settings and is thought to play a crucial role in social interactions. Previous studies have shown that the perception of a simple finger movement activates a shared representation of the observed and executed movements, which then elicits automatic imitation. However, relatively few studies have examined whether automatic imitation is limited to simple single-finger movements or whether it can be produced using a different automatic imitation paradigm with more complex sequential movements. Therefore, this study conducted three experiments in which participants observed the sequential movements of a model and then executed a compatible (similar) action or an incompatible (different) action involving the hand or foot in response to number cues that indicated the sequence for moving their hands or feet. The delay to onset of participants' initial hand or foot movements was calculated. Participants consistently executed compatible actions faster than incompatible actions. In particular, the results showed an imitative compatibility effect with a human stimulus but not an inanimate stimulus. These results demonstrate that automatic imitation occurs during more complex movements that require memory.

Does the threat of COVID-19 modulate automatic imitation?

The tendency to involuntarily imitate the actions of others (automatic imitation) can be modulated by social affiliative cues. Here, we explored whether the disruption to our social lives caused by the COVID-19 pandemic may subsequently influence automatic imitation. Three groups were initially presented a sentence comprehension task that featured either neutral (control), safe or unsafe primes to COVID-19 infection. They then completed an automatic imitation task, where a numeric cue was presented alongside apparent motion of an index or middle finger, which was either compatible or incompatible with the required response. Reaction times were longer for the incompatible compared to compatible trials, and thus demonstrated automatic imitation. However, there was no influence of the primes indicating that automatic imitation was unaffected by the risk of COVID-19. The potential theoretical explanations and practical implications of pathogen avoidance and social bonding incentives are discussed with reference to pandemic events.

The Perceived Broad Group Emotional Climate Scale: Development and Validation With Chinese Community Residents and University Students

Perceived broad group emotional climate (PBGEC) is a perceived meso-environment emotion, which refers to individuals’ perceptions and experiences of the emotion climate when interacting with group members in daily life, and is not derived from individuals’ own emotions. The purpose of this study was to develop and validate a PBGEC scale (PBGECS) for Chinese community residents and university students. A total of 1,408 residents from Chongqing completed the survey of PBGECS, the present social attitude scale, the future social expectations scale, and the social wellbeing scale, which constituted Sample 1; A total of 607 college students from Nanchang completed the survey of PBGECS and the Positive and Negative Affect Scale, which constituted Sample 2. Exploratory factor analysis revealed a two-factor structure, including positive PBGEC (PBGEC-P) and negative PBGEC (PBGEC-N). Internal consistency was strong for each factor and the full-scale (α ≥ 0.83). Confirmatory factor analysis showed that the correlated two-factor model of PBGEC and the four-factor model (including PBGEC-P, PBGEC-N, individual positive affect, and individual negative affect) demonstrated the best fit to the data, which supported the structural validity of the PBGECS. The interpretive validity, cultural validity, and population validity of the scale were also proved by examining the relationship between PBGEC and socioeconomic status, social attitude, and social wellbeing, respectively. The results show that the PBGECS demonstrated satisfactory reliability and validity, which can be used to assesses the perceived emotion climate of an individual’s surrounding environment.

The Effects of Online Status on Self-Other Processing as Revealed by Automatic Imitation

High status individuals have been found to be less attuned to the behavior of others in the social environment. An important question is whether social status in an online setting affects social information processing in a way that resembles the known effects of real-world status on such processing. We examined differences in automatic imitation between Instagram “leaders” and “followers.” In Experiment 1, we found that followers exhibited more automatic imitation than leaders. Experiment 2 sought to establish whether this effect depended on status being salient, or whether it would occur spontaneously in the absence of priming. Results confirmed that thinking about status prior to the task is necessary for producing the pattern of effects in which high status individuals exhibit less automatic imitation than lower status individuals. We discuss our findings in relation to the effects of online status on self-other processing as assessed in the automatic imitation task.

Imitation in one's own presence: No specific effect of self-focus on imitation

Previous studies have reported that imitative responses may be modulated by top-down social factors such as self-focus. However, growing evidence suggests that such social factors may actually modulate domain-general processes such as spatially compatible responding, rather than specifically social processes such as imitation. In this study, we aimed to identify the cognitive processes being modulated under conditions of heightened or diminished self-focus. Participants performed a stimulus-response compatibility task which independently measures both spatial and imitative response tendencies, under two conditions: heightened self-focus, where the task was performed in the presence of two mirrors; and diminished self-focus, where the mirrors were covered. While participants were faster to respond to compatible trials than to incompatible trials, both imitatively and spatially, there was no significant modulation of either spatial or imitative compatibility by self-focus; although the magnitude of the modulation of spatial compatibility was numerically similar to the effect of self-focus on imitation found in previous studies. These results provide no evidence for an effect of self-focus on either social-specific, or domain-general, processes.

Dissociable effects of averted "gaze" on the priming of bodily representations and motor actions

Gaze direction is an important stimulus that signals key details about social (dis)engagement and objects in our physical environment. Here, we explore how gaze direction influences the perceiver's processing of bodily information. Specifically, we examined how averted versus direct gaze modifies the operation of effector-centered representations (i.e., specific fingers) versus movement-centered representations (i.e., finger actions). Study 1 used a stimulus-response compatibility paradigm that tested the priming of a relevant effector or relevant movement, after observing videos of direct or averted gaze. We found a selective priming of relevant effectors, but only after averted gaze videos. Study 2 found similar priming effects with symbolic direction cues (averted arrows). Study 3 found that averted gaze cues do not influence generic spatial compatibility effects, and thus, are specific to body representations. In sum, this research suggests that both human and symbolic averted cues selectively prime relevant body-part representations, highlighting the dynamic interplay between our bodies, minds, and environments.

Challenges and opportunities for top-down modulation research in cognitive psychology

Studying social modulation of cognitive processes holds much promise for illuminating how, where, when and why social factors influence how we perceive and act in the world, as well as providing insight into the underlying cognitive mechanisms. This is no small objective; it reflects an ambitious programme of research. At present, based on the modal theoretical and methodological approach, we suggest that several challenges exist to achieving such lofty aims. These challenges span an overreliance on a simplistic dichotomy between "top-down" and "bottom-up" modulation, a lack of specificity about mechanisms that renders clear interpretations difficult, and theories that largely test against null hypotheses. We suggest that these challenges present several opportunities for new research and we encourage the field to abandon simplistic dichotomies and connect much more with existing research programmes such as semantics, memory and attention, which have all built diverse research platforms over many decades and that can help shape how social modulation is conceptualised and studied from a cognitive and brain perspective. We also outline ways that stronger theoretical positions can be taken, which avoid comparing to null hypotheses, and endorse methodological reform through fully embracing proposals from the open science movement and "credibility revolution". We feel that by taking these opportunities, the field will have a better chance of reaching its potential to build a cumulative science of social modulation that can inform understanding of basic cognitive and brain systems, as well as real-life social interactions and the varied abilities observed across the Autism Spectrum.

Being mimicked affects inhibitory mechanisms of imitation

This study investigated the effects of being mimicked on automatic imitation indices and social cohesion. 180 female participants were either interactively mimicked or anti-mimicked. In the mimicry condition, a confederate topographically aligned, during anti-mimicry, misaligned, their behavior to the participants. Being mimicked may evoke a sense of overlap between self and other generated movements. This so-created self-other overlap may generalize to other forms of imitation and social cohesion. Here, we investigated the effects of being mimicked on automatic imitation indices, using the Imitation-Inhibition Task. These indices are the baseline corrected facilitation and inhibition index, and the interference index which depicts the relation between facilitation and inhibition. In case of a generalized self-other overlap, we expect an increase in the facilitation, inhibition, and interference index, after the Mimicry as compared to the Anti-Mimicry condition. We furthermore predicted that the modulation of the indices would predict higher social cohesion ratings. Yet, our results showed a lower inhibition index after being mimicked, respectively an increase after Anti-Mimicry, with no effects on social cohesion ratings. This suggests that potential self-other overlap after being mimicked does not generalize to automatic imitation indices. Instead, being mimicked may have increased self-regulatory processes, and task performance.

Developmental trajectory of interpersonal motor alignment: Positive social effects and link to social cognition

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Interpersonal motor alignment (IMA) has positive effects on healthy social life.

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IMA - mimicry, synchrony, automatic imitation - is studied throughout development.

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It relies on motor resonance brain mechanisms identified throughout development.

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It is modulated by contextual and personal factors.

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IMA is underinvestigated in adolescence, yet it may aid to enhance resilience.

Interpersonal motor alignment is a ubiquitous behavior in daily social life. It is a building block for higher social cognition, including empathy and mentalizing and promotes positive social effects. It can be observed as mimicry, synchrony and automatic imitation, to name a few. These phenomena rely on motor resonance processes, i.e., a direct link between the perception of an action and its execution. While a considerable literature debates its underlying mechanisms and measurement methods, the question of how motor alignment comes about and changes in ontogeny all the way until adulthood, is rarely discussed specifically. In this review we will focus on the link between interpersonal motor alignment, positive social effects and social cognition in infants, children, and adolescents, demonstrating that this link is present early on in development. Yet, in reviewing the existing literature pertaining to social psychology and developmental social cognitive neuroscience, we identify a knowledge gap regarding the healthy developmental changes in interpersonal motor alignment especially in adolescence.

The Effect of Money Priming on Self-Focus in the Imitation-Inhibition Task

Abstract. The self-sufficiency hypothesis suggests that priming individuals with money makes them focus more strongly on themselves than on others. However, recently, research supporting this claim has been heavily criticized and some attempts to replicate have failed. A reason for the inconsistent findings in the field may lay in the common use of explicit measures, because they tend to rely on one or just a few items and are thus prone to demand effects and low reliability. In the present research, we administered, in two experiments, the imitation-inhibition task – a robust, unobtrusive, and reliable paradigm that is sensitive to self-other focus on a trial-by-trial basis. A pilot study found an increased focus on the self as compared to others when primed with money. Building on this finding, a preregistered high-powered experiment replicated this effect, suggesting that money primes may indeed increase a focus on the self. An additionally carried out meta-analysis indicates that automatic imitation is modulated by self-other focus and that money primes lead to a smaller focus on the self than conventional methods. Overall, the found effects are rather small and several limitations, such as order effects, call for a cautious interpretation of the findings.

The role of transients in action observation

A large number of studies have now described the various ways in which the observation of another person's dynamic movement can influence the speed with which the observer is able to prepare a motor action themselves. The typical results are most often explained with reference to theories that link perception and action. Such theories argue that the cognitive structures associated with each share common representations. Consequently, action preparation and action observation are often said to be functionally equivalent. However, the dominance of these theories in explaining action observation effects has masked the potential contribution from processes associated with the detection of low-level "transients" resulting from observing a body movement, such as motion and sound. In the present review, we describe work undertaken in one particular action observation phenomenon ("social inhibition of return") and show that the transient account provides the best explanation of the effect. We argue that future work should consider attention capture and orienting as a potential contributing factor to action observation effects more broadly.

The influence of prosocial priming on visual perspective taking and automatic imitation

Imitation and perspective taking are core features of non-verbal social interactions. We imitate one another to signal a desire to affiliate and consider others' points of view to better understand their perspective. Prior research suggests that a relationship exists between prosocial behaviour and imitation. For example, priming prosocial behaviours has been shown to increase imitative tendencies in automatic imitation tasks. Despite its importance during social interactions, far less is known about how perspective taking might relate to either prosociality or imitation. The current study investigates the relationship between automatic imitation and perspective taking by testing the extent to which these skills are similarly modulated by prosocial priming. Across all experimental groups, a surprising ceiling effect emerged in the perspective taking task (the Director's Task), which prevented the investigation of prosocial priming on perspective taking. A comparison of other studies using the Director's Task shows wide variability in accuracy scores across studies and is suggestive of low task reliability. In addition, despite using a high-power design, and contrary to three previous studies, no effect of prosocial prime on imitation was observed. Meta-analysing all studies to date suggests that the effects of prosocial primes on imitation are variable and could be small. The current study, therefore, offers caution when using the computerised Director's Task as a measure of perspective taking with adult populations, as it shows high variability across studies and may suffer from a ceiling effect. In addition, the results question the size and robustness of prosocial priming effects on automatic imitation. More generally, by reporting null results we hope to minimise publication bias and by meta-analysing results as studies emerge and making data freely available, we hope to move towards a more cumulative science of social cognition.

Enhanced Automatic Action Imitation and Intact Imitation-Inhibition in Schizophrenia

Imitation plays a key role in social learning and in facilitating social interactions and likely constitutes a basic building block of social cognition that supports higher-level social abilities. Recent findings suggest that patients with schizophrenia have imitation impairments that could contribute to the social impairments associated with the disorder. However, extant studies have specifically assessed voluntary imitation or automatic imitation of emotional stimuli without controlling for potential confounders. The imitation impairments seen might therefore be secondary to other cognitive, motoric, or emotional deficits associated with the disorder. To overcome this issue, we used an automatic imitation paradigm with nonemotional stimuli to assess automatic imitation and the top-down modulation of imitation where participants were required to lift one of 2 fingers according to a number shown on the screen while observing the same or the other finger movement. In addition, we used a control task with a visual cue in place of a moving finger, to isolate the effect of observing finger movement from other visual cueing effects. Data from 33 patients (31 medicated) and 40 matched healthy controls were analyzed. Patients displayed enhanced imitation and intact top-down modulation of imitation. The enhanced imitation seen in patients may have been medication induced as larger effects were seen in patients receiving higher antipsychotic doses. In sum, we did not find an imitation impairment in schizophrenia. The results suggest that previous findings of impaired imitation in schizophrenia might have been due to other cognitive, motoric, and/or emotional deficits.

The relationship between inhibition of automatic imitation and personal cognitive styles

Background

Previous studies have demonstrated the importance of the inhibition of automatic imitation in social interactions. Additionally, cognitive traits are known to vary among individuals. According to the empathizing-systemizing (E-S) model, personality can be quantified by empathizing and systemizing drives in causal cognition. Since inhibition of automatic imitation is strongly related to social cognition, the level of inhibition may be explained by personal cognitive traits. Thus, the current study tested whether cognitive traits, measured based on the E-S model, correlated with levels of automatic imitation inhibition.

Methods

The empathizing-systemizing quotient (EQ-SQ) questionnaire was used to assess cognitive traits. Behavioral and electroencephalogram data were acquired during the imitation inhibition task. In addition to reaction time, based on signal detection theory, task sensitivity and response bias were calculated from reaction data. As a physiological measure of automatic imitation, mu rhythm power suppression was calculated from electroencephalogram data. Congruency effects for reaction time and electroencephalogram measures were calculated by subtracting congruent trials from incongruent trails.

Results

Correlation analyses between cognitive traits and task measures were conducted. There was a negative correlation found between EQ score and the behavioral index reflecting task performance. Moreover, a negative correlation was found between SQ score and the congruency effect on mu suppression.

Conclusions

Participants with higher EQ scored relatively lower in inhibiting their responses. Conversely, high SQ participants showed successful inhibition of mu suppression. The imitative tendency may disturb the inhibition of response. The correlation between SQ and mu index suggests the involvement of domain-general information processing on imitation inhibition; however, further research is required to determine this. Since different correlations were found for behavioral and physiological measures, these measures may reflect different steps of information processing for successful task execution. Through correlational analysis, a possible relation was identified between the inhibiting process of automatic imitation and personal cognitive styles on social interactions.

Top-down attentional factors modulate action priming in reach-to-grasp action

Previous studies report that viewing exaggerated, high-lifting reaches (versus direct reaches) primes higher vertical deviation in wrist trajectory in the observer's subsequent reaches (trajectory priming), but it is unclear to what extent this effect depends upon task instructions relevant to top-down attention. In two experiments, participants were instructed to gaze at a dot presented on a large monitor for a colour-change go signal that cued them to execute a direct reach to a target. In the background, the monitor also displayed life-sized films of a human model. The films were of the model either remaining still or reaching to grasp a target with either a direct trajectory or an exaggerated, high-lifting trajectory. When the dot traced the human model's wrist throughout her movement, a robust trajectory priming effect emerged. When the dot remained stationary in a central location but the human model reached in the background, the human model's trajectory did not alter the participants' trajectories. Finally, when the dot traced exaggerated and direct trajectories and the human model remained stationary, the dot's movement produced an attenuated, non-significant trajectory priming effect. These findings show that top-down attentional factors modulate trajectory priming. In addition, a moving non-human stimulus does not produce the same degree of action priming when contextual factors make salient its independence of human agency and/or intention.

Anticipating actions and corticospinal excitability: A preregistered motor TMS experiment

Past research on action observation and imitation suggests that observing a movement activates a corresponding motor representation in the observer. However, recent research suggests that individuals may not only reflexively simulate the observed behavior but also simulate and engage in anticipated action without another person actually engaging in it. For example, it has been demonstrated that observing a triggering event (i.e., nose wrinkling) that potentially leads to the anticipation of an action (i.e., nose scratching) increases the likelihood that the observer will perform that action. In the present research, we applied motor Transcranial Magnetic Stimulation (TMS) to investigate such anticipated social action effects at the neurophysiological level within a trial-by-trial measure. While a pilot study suggests that observing nose wrinkling elicits stronger motor evoked potentials (MEPs) in participants' biceps muscles than observing control events, this effect could not be fully replicated in a preregistered study. Although a post hoc meta-analysis across both studies supports the general hypothesis, these results need to be taken cautiously. Implications of the results reported in the manuscript are discussed.

Impression or expression? The influence of self-monitoring on the social modulation of motor contagion

Social primes (pro-social, anti-social) can modulate mimicry behaviour. To date, these social modulation effects have been explained by the primed incentive to affiliate with another (Social Top-Down Response Modulation; STORM) and the primed active-self-concept leading to behaviour that is either consistent or inconsistent with the primed-construct (Active-Self account). This study was designed to explore the explanatory power of each of these accounts and thereby gain a greater understanding of how social modulation unfolds. To do this, we assessed social modulation of motor contagion in individuals high or low in self-monitoring. It was reasoned that high self-monitors would modulate mimicry according to the primed social incentive, whereas low self-monitors would modulate according to the primed active-self-concept. Participants were primed with a pro-social and anti-social cue in the first-person and third-person perspective. Next, they completed an interpersonal observation–execution task featuring the simultaneous observation and execution of arm movements that were either congruent or incongruent to each other. Results showed increased incongruent movement deviation (motor contagion) for the anti-social compared to the pro-social prime in the high self-monitors only. Findings support the STORM account of mimicry by showing observers modulate behaviour based on the social incentive underpinning an interpersonal exchange.

Mimicking and anticipating others' actions is linked to Social Information Processing

It is widely known that individuals frequently imitate each other in social situations and that such mimicry fulfills an important social role in the sense that it functions as a social glue. With reference to the anticipated action effect, it has recently been demonstrated that individuals do not only imitate others, but also engage in anticipated action before the observed person starts engaging in that action. Interestingly, both phenomena (i.e., mimicry and anticipated action) rely on tracking others’ social behavior. Therefore, in the present research we investigated whether mimicry and anticipated action are related to social abilities as indicated by measures of social intelligence. The results demonstrate for the first time that mimicry as well as anticipated action is correlated with an important aspect of social intelligence—namely the ability to process social information. Theoretical implications and limitations are discussed.

Mimicry and automatic imitation are not correlated

It is widely known that individuals have a tendency to imitate each other. However, different psychological disciplines assess imitation in different manners. While social psychologists assess mimicry by means of action observation, cognitive psychologists assess automatic imitation with reaction time based measures on a trial-by-trial basis. Although these methods differ in crucial methodological aspects, both phenomena are assumed to rely on similar underlying mechanisms. This raises the fundamental question whether mimicry and automatic imitation are actually correlated. In the present research we assessed both phenomena and did not find a meaningful correlation. Moreover, personality traits such as empathy, autism traits, and traits related to self- versus other-focus did not correlate with mimicry or automatic imitation either. Theoretical implications are discussed.

The influence of intrapersonal sensorimotor experiences on the corticospinal responses during action-observation

The coupling of perception and action has been strongly indicated by evidence that the observation of an action primes a response in the observer. It has been proposed that these primed responses may be inhibited when the observer is able to more closely distinguish between self- and other-generated actions - the greater the distinction, then the greater the inhibition of the primed response. This self-other distinction is shown to be enhanced following a period of visual feedback of self-generated action. The present study was designed to examine how sensorimotor experiences pertaining to self-generated action affect primed responses from observed actions. Single-pulse transcranial magnetic stimulation was used to investigate corticospinal activity elicited during the observation of index- and little-finger actions before and after training (self-generated action). For sensorimotor training, participants executed finger movements with or without visual feedback of their own movement. Results showed that the increases in muscle-specific corticospinal activity elicited from action-observation persisted after training without visual feedback, but did not emerge following training with visual feedback. This inhibition in corticospinal activity during action-observation following training with vision could have resulted from the refining of internal models of self-generated action, which then led to a greater distinction between "self" and "other" actions.

From movement kinematics to social cognition: the case of autism

The way in which we move influences our ability to perceive, interpret and predict the actions of others. Thus movements play an important role in social cognition. This review article will appraise the literature concerning movement kinematics and motor control in individuals with autism, and will argue that movement differences between typical and autistic individuals may contribute to bilateral difficulties in reciprocal social cognition.

Orthogonal-compatibility effects confound automatic imitation: implications for measuring self-other distinction

Accurate distinction between self and other representations is fundamental to a range of social cognitive capacities, and understanding individual differences in this ability is an important aim for psychological research. This demands accurate measures of self-other distinction (SOD). The present study examined an experimental paradigm employed frequently to measure SOD in the action domain; specifically, we evaluated the rotated finger-action stimuli used increasingly to measure automatic imitation (AI). To assess the suitability of these stimuli, we compared AI elicited by different action stimuli to the performance on a perspective-taking task believed to measure SOD in the perception domain. In two separate experiments we reveal three important findings: firstly, we demonstrate a strong confounding influence of orthogonal-compatibility effects on AI elicited by certain rotated stimuli. Second, we demonstrate the potential for this confounding influence to mask important relationships between AI and other measures of SOD; we observed a relationship between AI and perspective-taking performance only when the former was measured in isolation of orthogonality compatibility. Thirdly, we observed a relationship between these two performance measures only in a sub-group of individuals exhibiting a pure form of AI. Furthermore, this relationship revealed a self-bias in SOD-reduced AI was associated with increased egocentric misattributions in perspective taking. Together, our findings identify an important methodological consideration for measures of AI and extend previous research by showing an egocentric style of SOD across action and perception domains.

Group Dynamics in Automatic Imitation

Imitation-matching the configural body movements of another individual-plays a crucial part in social interaction. We investigated whether automatic imitation is not only influenced by who we imitate (ingroup vs. outgroup member) but also by the nature of an expected interaction situation (competitive vs. cooperative). In line with assumptions from Social Identity Theory), we predicted that both social group membership and the expected situation impact on the level of automatic imitation. We adopted a 2 (group membership target: ingroup, outgroup) x 2 (situation: cooperative, competitive) design. The dependent variable was the degree to which participants imitated the target in a reaction time automatic imitation task. 99 female students from two British Universities participated. We found a significant two-way interaction on the imitation effect. When interacting in expectation of cooperation, imitation was stronger for an ingroup target compared to an outgroup target. However, this was not the case in the competitive condition where imitation did not differ between ingroup and outgroup target. This demonstrates that the goal structure of an expected interaction will determine the extent to which intergroup relations influence imitation, supporting a social identity approach.

Self-other control processes in social cognition: from imitation to empathy

We review the evidence that an ability to achieve a precise balance between representing the self and representing other people is crucial in social interaction. This ability is required for imitation, perspective-taking, theory of mind and empathy; and disruption to this ability may contribute to the symptoms of clinical and sub-clinical conditions, including autism spectrum disorder and mirror-touch synaesthesia. Moving beyond correlational approaches, a recent intervention study demonstrated that training participants to control representations of the self and others improves their ability to control imitative behaviour, and to take another's visual perspective. However, it is unclear whether these effects apply to other areas of social interaction, such as the ability to empathize with others. We report original data showing that participants trained to increase self-other control in the motor domain demonstrated increased empathic corticospinal responses (Experiment 1) and self-reported empathy (Experiment 2), as well as an increased ability to control imitation. These results suggest that the ability to control self and other representations contributes to empathy as well as to other types of social interaction.

Judging the Ability of Friends and Foes

Collaboration leads us to judge our own ability to be more similar to our collaborators and their ability to be more similar to our own, while competition leads us to exaggerate the gap between our abilities. How does this happen and what does it mean?

The modulation of motor contagion by intrapersonal sensorimotor experience

Sensorimotor experiences can modify the internal models for action. These modifications can govern the discrepancies between predicted and actual sensory consequences, such as distinguishing self- and other-generated actions. This distinction may also contribute toward the inhibition of movement interference, which is strongly associated with the coupling of observed and executed actions. Therefore, movement interference could be mediated by the sensorimotor experiences underlying the self-other distinction. The present study examined the impact of sensorimotor experiences on involuntary movement interference (motor contagion). Participants were required to complete a motor contagion paradigm in which they executed horizontal arm movements while observing congruent (horizontal) or incongruent (vertical) arm movements of a model. This task was completed before and after a training protocol in which participants executed the same horizontal arm movements in the absence of the model stimuli. Different groups of participants trained with or without vision of their moving limb. Analysis of participants who were predisposed to motor contagion (involuntary movement interference during the observation of incongruent movements) revealed that the no vision group continued to demonstrate contagion at post-training, although the vision group did not. We propose that the vision group were able to integrate the visual afferent information with an internal model for action, which effectively refines the ability to match self-produced afferent and efferent sources of information during response-execution. This enhanced matching allows for a better distinction between self and other, which in turn, mediates the inhibition of motor contagion.

Status and Power Do Not Modulate Automatic Imitation of Intransitive Hand Movements

The tendency to mimic the behaviour of others is affected by a variety of social factors, and it has been argued that such “mirroring” is often unconsciously deployed as a means of increasing affiliation during interpersonal interactions. However, the relationship between automatic motor imitation and status/power is currently unclear. This paper reports five experiments that investigated whether social status (Experiments 1, 2, and 3) or power (Experiments 4 and 5) had a moderating effect on automatic imitation (AI) in finger-movement tasks, using a series of different manipulations. Experiments 1 and 2 manipulated the social status of the observed person using an associative learning task. Experiment 3 manipulated social status via perceived competence at a simple computer game. Experiment 4 manipulated participants’ power (relative to the actors) in a card-choosing task. Finally, Experiment 5 primed participants using a writing task, to induce the sense of being powerful or powerless. No significant interactions were found between congruency and social status/power in any of the studies. Additionally, Bayesian hypothesis testing indicated that the null hypothesis should be favoured over the experimental hypothesis in all five studies. These findings are discussed in terms of their implications for AI tasks, social effects on mimicry, and the hypothesis of mimicry as a strategic mechanism to promote affiliation.

Cognitive mechanisms for responding to mimicry from others

Compared to our understanding of neurocognitive processes involved producing mimicry, the downstream consequences of being mimicked are less clear. A wide variety of positive consequences of mimicry, such as liking and helping, have been reported in behavioural research. However, an in-depth review suggests the link from mimicry to liking and other positive outcomes may be fragile. Positive responses to mimicry can break down due to individual factors and social situations where mimicry may be unexpected. It remains unclear how the complex behavioural effects of mimicry relate to neural systems which respond to being mimicked. Mimicry activates regions associated with mirror properties, self-other processing and reward. In this review, we outline three potential models linking these regions with cognitive consequences of being mimicked. The models suggest that positive downstream consequences of mimicry may depend upon self-other overlap, detection of contingency or low prediction error. Finally, we highlight limitations with traditional research designs and suggest alternative methods for achieving highly ecological validity and experimental control. We also highlight unanswered questions which may guide future research.

Intact Automatic Imitation and Typical Spatial Compatibility in Autism Spectrum Disorder: Challenging the Broken Mirror Theory

A lack of imitative behavior is frequently described as a core feature of Autism Spectrum Disorder (ASD), and is consistent with claims of mirror neuron system dysfunction in these individuals. Previous research has questioned this characterization of ASD however, arguing that when tests of automatic imitation are used--which do not require higher-level cognitive processing--imitative behavior is intact or even enhanced in individuals with ASD. In Experiment 1, 60 adult individuals with ASD and a matched Control group completed an automatic imitation task in which they were required to perform an index or a middle finger lift while observing a hand making either the same, or the alternate, finger movement. Both groups demonstrated a significant imitation effect whereby actions were executed faster when preceded by observation of the same action, than when preceded by the alternate action. The magnitude of this "imitation effect" was statistically indistinguishable in the ASD and Control groups. Experiment 2 utilized an improved automatic imitation paradigm to demonstrate that, when automatic imitation effects are isolated from those due to spatial compatibility, increasing autism symptom severity is associated with an increased tendency to imitate. Notably, there was no association between autism symptom severity and spatial compatibility, demonstrating the specificity of the link between ASD symptoms and increased imitation. These results provide evidence against claims of a lack of imitative behavior in ASD, and challenge the "Broken Mirror Theory of Autism."

Investigating the Relationship between Stable Personality Characteristics and Automatic Imitation

Automatic imitation is a cornerstone of nonverbal communication that fosters rapport between interaction partners. Recent research has suggested that stable dimensions of personality are antecedents to automatic imitation, but the empirical evidence linking imitation with personality traits is restricted to a few studies with modest sample sizes. Additionally, atypical imitation has been documented in autism spectrum disorders and schizophrenia, but the mechanisms underpinning these behavioural profiles remain unclear. Using a larger sample than prior studies (N=243), the current study tested whether performance on a computer-based automatic imitation task could be predicted by personality traits associated with social behaviour (extraversion and agreeableness) and with disorders of social cognition (autistic-like and schizotypal traits). Further personality traits (narcissism and empathy) were assessed in a subsample of participants (N=57). Multiple regression analyses showed that personality measures did not predict automatic imitation. In addition, using a similar analytical approach to prior studies, no differences in imitation performance emerged when only the highest and lowest 20 participants on each trait variable were compared. These data weaken support for the view that stable personality traits are antecedents to automatic imitation and that neural mechanisms thought to support automatic imitation, such as the mirror neuron system, are dysfunctional in autism spectrum disorders or schizophrenia. In sum, the impact that personality variables have on automatic imitation is less universal than initial reports suggest.

Automatic imitation in a rich social context with virtual characters

It has been well established that people respond faster when they perform an action that is congruent with an observed action than when they respond with an incongruent action. Here we propose a new method of using interactive Virtual Characters (VCs) to test if social congruency effects can be obtained in a richer social context with sequential hand-arm actions. Two separate experiments were conducted, exploring if it is feasible to measure spatial congruency (Experiment 1) and anatomical congruency (Experiment 2) in response to a VC, compared to the same action sequence indicated by three virtual balls. In Experiment 1, we found a robust spatial congruency effect for both VC and virtual balls, modulated by a social facilitation effect for participants who felt the VC was human. In Experiment 2 which allowed for anatomical congruency, a form by congruency interaction provided evidence that participants automatically imitate the actions of the VC but do not imitate the balls. Our method and results build a bridge between studies using minimal stimuli in automatic interaction and studies of mimicry in a rich social interaction, and open new research venue for future research in the area of automatic imitation with a more ecologically valid social interaction.

Top-down social modulation of interpersonal observation-execution

Cyclical upper limb movement can involuntarily deviate from its primary movement axis when the performer concurrently observes incongruent biological motion (i.e. interpersonal observation-execution). The current study examined the social modulation of such involuntary motor interference using a protocol that reflected everyday social interactions encountered in a naturalistic social setting. Eighteen participants executed cyclical horizontal arm movements during the observation of horizontal (congruent) or curvilinear (incongruent) biological motion. Both prior to, and during the interpersonal observation-execution task, participants also received a series of social words designed to prime a pro-social or anti-social attitude. The results showed greater orthogonal movement deviation, and thus interference, for the curvilinear compared to horizontal stimuli. Importantly, and opposite to most of the previous findings from work on automatic imitation and mimicry, there was a greater interference effect for the anti-social compared to pro-social prime condition. These findings demonstrate the importance of interpreting the context of social primes, and strongly support predictions of a comparison between the prime construct and the self-concept/-schema and the top-down response modulation of social incentives.

Task-dependent and distinct roles of the temporoparietal junction and inferior frontal cortex in the control of imitation

The control of neurological networks supporting social cognition is crucially important for social interaction. In particular, the control of imitation is directly linked to interaction quality, with impairments associated with disorders characterized by social difficulties. Previous work suggests inferior frontal cortex (IFC) and the temporoparietal junction (TPJ) are involved in controlling imitation, but the functional roles of these areas remain unclear. Here, transcranial direct current stimulation (tDCS) was used to enhance cortical excitability at IFC and the TPJ prior to the completion of three tasks: (i) a naturalistic social interaction during which increased imitation is known to improve rapport, (ii) a choice reaction time task in which imitation needs to be inhibited for successful performance and (iii) a non-imitative control task. Relative to sham stimulation, stimulating IFC improved the context-dependent control of imitation-participants imitated more during the social interaction and less during the imitation inhibition task. In contrast, stimulating the TPJ reduced imitation in the inhibition task without affecting imitation during social interaction. Neither stimulation site affected the non-imitative control task. These data support a model in which IFC modulates imitation directly according to task demands, whereas TPJ controls task-appropriate shifts in attention toward representation of the self or the other, indirectly impacting upon imitation.

Copying you copying me: interpersonal motor co-ordination influences automatic imitation

Moving in a co-ordinated fashion with another individual changes our behaviour towards them; we tend to like them more, find them more attractive, and are more willing to co-operate with them. It is generally assumed that this effect on behaviour results from alterations in representations of self and others. Specifically, through neurophysiological perception-action matching mechanisms, interpersonal motor co-ordination (IMC) is believed to forge a neural coupling between actor and observer, which serves to blur boundaries in conceptual self-other representations and causes positive views of the self to be projected onto others. An investigation into this potential neural mechanism is lacking, however. Moreover, the specific components of IMC that might influence this mechanism have not yet been specified. In the present study we exploited a robust behavioural phenomenon--automatic imitation--to assess the degree to which IMC influences neural action observation-execution matching mechanisms. This revealed that automatic imitation is reduced when the actions of another individual are perceived to be synchronised in time, but are spatially incongruent, with our own. We interpret our findings as evidence that IMC does indeed exert an effect on neural perception-action matching mechanisms, but this serves to promote better self-other distinction. Our findings demonstrate that further investigation is required to understand the complex relationship between neural perception-action coupling, conceptual self-other representations, and social behaviour.

The role of the right temporoparietal junction in the control of imitation

Controlling neural representations of the self and other people is fundamental to social cognition. Brain imaging studies have implicated the right temporoparietal junction (rTPJ) in this ability, but causal evidence for its role is lacking. A debate is also ongoing regarding whether the control of, or switching between, self and other representations is a specialized or domain-general process: the rTPJ's well-established role in reorienting attention supports a domain-general process, but a role specific to social cognition has also been proposed. Neuronavigated repetitive transcranial magnetic stimulation was used to target the rTPJ (and a control mid-occipital site) during a task requiring participants to switch between representations of others' actions on both a social and a nonsocial level, by manipulating imitative and spatial compatibility simultaneously and independently. Both imitative and spatial compatibility effects were apparent on response times; however, the effect of imitative compatibility was significantly stronger, indicating less control of imitation, during stimulation of the rTPJ relative to the control site. This suggests that the rTPJ is involved in switching between self and other representations, and further, that this process may not be entirely domain general.

The controlled imitation task: a new paradigm for studying self-other control

In the automatic imitation task (AIT) participants make a cued response during simultaneous exposure to a congruent or incongruent action made by another agent. Participants are slower to make the cued response on incongruent trials, which is thought to reflect conflict between the motor representation activated by the cue and the motor representation activated by the observed action. On incongruent trials, good performance requires the capacity to suppress the imitative action, in favor of producing the cued response. Here, we introduce a new experimental paradigm that complements the AIT, and is therefore a useful task for studying the control of self and other activated representations. In what we term the "Controlled Imitation Task (CIT)", participants are cued to make an action, but on 50% of trials, within 100 ms of this cue, an on-screen hand makes a congruent or incongruent action. If the onscreen hand moves, the participant must suppress the cued response, and instead imitate the observed action as quickly and accurately as possible. In direct contrast to the AIT, the CIT requires suppression of a self-activated motor representation, and prioritization of an imitative response. In experiment 1, we report a robust pattern of interference effects in the CIT, such that participants are slower to make the imitative response on incongruent compared to congruent trials. In experiment 2, we replicate this effect while including a non-imitative spatial-cue control condition to show that the effect is particularly robust for imitative response tendencies per se. Owing to the essentially opposite control requirements of the CIT versus the AIT (i.e., suppression of self-activated motor representations instead of suppression of other-activated motor representations), we propose that this new task is a potentially informative complementary paradigm to the AIT that can be used in studies of self-other control processes.

Understanding the role of the 'self' in the social priming of mimicry

People have a tendency to unconsciously mimic other's actions. This mimicry has been regarded as a prosocial response which increases social affiliation. Previous research on social priming of mimicry demonstrated an assimilative relationship between mimicry and prosociality of the primed construct: prosocial primes elicit stronger mimicry whereas antisocial primes decrease mimicry. The present research extends these findings by showing that assimilative and contrasting prime-to-behavior effect can both happen on mimicry. Specifically, experiment 1 showed a robust contrast priming effect where priming antisocial behaviors induces stronger mimicry than priming prosocial behaviors. In experiment 2, we manipulated the self-relatedness of the pro/antisocial primes and further revealed that prosocial primes increase mimicry only when the social primes are self-related whereas antisocial primes increase mimicry only when the social primes are self-unrelated. In experiment 3, we used a novel cartoon movie paradigm to prime pro/antisocial behaviors and manipulated the perspective-taking when participants were watching these movies. Again, we found that prosocial primes increase mimicry only when participants took a first-person point of view whereas antisocial primes increase mimicry only when participants took a third-person point of view, which replicated the findings in experiment 2. We suggest that these three studies can be best explained by the active-self theory, which claims that the direction of prime-to-behavior effects depends on how primes are processed in relation to the ‘self’.

Automatic imitation is automatic, but less so for narcissists

Imitation is a fundamentally important human capability and has been the topic of considerable research in the behavioural sciences. One paradigm for investigating the basic nature of imitation is the "automatic imitation" paradigm. In this paradigm, participants are symbolically cued to make a particular response, whilst being incidentally exposed to a congruent or incongruent motor action performed by another person. The robust finding is that when the incidental action is incongruent with the cued action, participants are slower to respond than when it is congruent. Despite the name given to this paradigm, the extent to which the imitative tendency involved is actually automatic remains unclear. Here, we manipulated the probability of congruent and incongruent trials within blocks to assess the effects of expectation on the imitative process. In addition, we determined whether an individual difference variable related to how people process others' behaviour-narcissism-affected the automaticity of imitation. Our results confirm that imitation as observed in this paradigm is robust in the face of expectation. However, the degree to which expectation modulates automatic imitation was enhanced for individuals who scored higher on a narcissism inventory. Together, these results suggest that imitation in the automatic imitation paradigm is indeed largely automatic, but that individual differences in narcissism can change the extent to which imitative behaviour manifests.

Atypical social modulation of imitation in autism spectrum conditions

Appropriate modulation of imitation according to social context is important for successful social interaction. In the present study we subliminally primed high-functioning adults with ASC and age- and IQ-matched controls with either a pro- or non- social attitude. Following priming, an automatic imitation paradigm was used to acquire an index of imitation. Whereas imitation levels were higher for pro-socially primed relative to non-socially primed control participants, there was no difference between pro- and non- socially primed individuals with ASC. We conclude that high-functioning adults with ASC demonstrate atypical social modulation of imitation. Given the importance of imitation in social interaction we speculate that difficulties with the modulation of imitation may contribute to the social problems characteristic of ASC.

The antecedents and consequences of human behavioral mimicry

Behavioral mimicry--the automatic imitation of gestures, postures, mannerisms, and other motor movements--is pervasive in human interactions. The current review focuses on two recent themes in the mimicry literature. First, an analysis of the moderators of mimicry uncovers the various motivational, social, emotional, and personality factors that lead to more or less mimicry of an interaction partner in a given situation. Second, a significant amount of recent research has identified important downstream consequences of mimicking or being mimicked by another person. These include not only increased prosociality between interactants, but also unexpected effects on the individual, such as cognitive processing style, attitudes, consumer preferences, self-regulatory ability, and academic performance. Behavioral mimicry is also placed in its broader context: a form of interpersonal coordination. It is compared to interactional synchrony and other social contagion effects, including verbal, goal, and emotional contagion and attitudinal convergence.