In the eye of the beholder: Social traits predict motor simulation during social gaze

Abstract

Previous research has robustly demonstrated that mutual eye contact between actor and observer promotes the simulation of perceived actions into the observer’s own motor system, which in turn facilitates successful social perception and communication. However, the socially relevant connotation embedded in eye contact may be different for individuals with differing social traits. Here, we investigated whether normal (i.e. non-clinical) variability in self-reported social responsiveness, social anxiety and interpersonal relationship style (secure, avoidant or anxious attachment) is related to one’s ability to show enhanced motor resonance during dyadic eye contact. This was investigated in a representative dataset of 124 adult participants (age range: 18-35 years) who underwent transcranial magnetic stimulation (TMS) while observing an actor performing simple hand actions and simultaneously engaging in mutual eye contact or gazing away from the observer. Motor evoked potentials were collected as an index of motor resonance. Univariate analyses specifically highlighted the unique role of social responsiveness and secure attachment in shaping motor resonance, indicating that socially adaptive motor resonance during dyadic gaze (i.e. direct > averted) was only observed in participants displaying high levels of these traits. Furthermore, a multivariate clustering analysis identified three data-driven social trait profiles predominantly defined by attachment style, showing a clear differentiation in motor resonant patterns upon dyadic gaze cues in accordance with a recent neurobiological framework of attachment. Together, results demonstrate that motor resonance within a given social interaction is a sensitive tracker of socio-interactive engagement, which allows to capture (sub)clinical inter-individual variation in relevant social traits.