Empathy Modulates the Reward Value of Mimicry: Implications for Imitation Based Interventions for Autism
Objectives: To directly test the reward value of mimicry, we measured the impact of being mimicked on preferential looking, using gaze duration as a proxy measure of reward consummation (i.e. longer gaze duration is associated with higher reward value). We further tested individual variability in this effect, as a function of trait empathy (as measured by Empathy Quotient, (EQ)).
Methods: 37 neurotypical adults (17 males) underwent a conditioning experiment in which they performed facial expressions (happy, sad, or neutral). Crucially, <1s after they started making the expression, they saw a video of a person making the same expression (Mimicking face) or another person making a different expression (AntiMimicking face). In the test phase, pairs of ‘Mimicking face’ and ‘AntiMimicking face’ were presented side-by-side on a gaze-tracking monitor. Further, subject’s ability to empathise was assessed via the Empathy Quotient (EQ). To ensure that any observed differences were not related to greater response conflict associated with a given face, we conducted a separate experiment (N=19) investigating the effect of spatial congruency on gaze behaviour.
Results: Participants showed longer gaze duration for Mimicking faces than AntiMimicking faces after conditioning, (controlling for any baseline difference in looking times for the two faces) (t=2.99, p=.005). No such pattern was detected when comparing spatially congruent vs. incongruent faces in the control paradigm. Further, the magnitude of the difference in gaze duration between Mimicking and AntiMimicking faces, was positively correlated with EQ (r=.319; p=.04).
Conclusions: These findings suggest that being mimicked by a face changes its reward value, which is indexed by longer gaze durations. This effect is not driven by different levels of response conflict associated with the different faces, as shown by the results of the control task. Further, this effect is greater in more empathic individuals, suggesting that empathy affects the interaction between mimicry and reward system, i.e. this link seems to be stronger in individuals with higher EQ. These results provide direct evidence for a potential reward-based mechanism through which imitation-based interventions in autism may work, and identify key dimensions of individual variation.