Gaze and body cues interplay during interactive requests

PLoS One. 2019 Oct 21;14(10):e0223591. doi: 10.1371/journal.pone.0223591. eCollection 2019.

Abstract

Although observing other's gaze and body movements provides a crucial source of information to successfully interact with other people, it remains unclear whether observers weigh differently these cues and whether the convergence of gaze and body's directions determines facilitation effects. Here we aim to shed more light on this issue by testing the reliance upon these cues from both a behavioral and a neurophysiological perspective in a social interactive context. In Experiment 1, we manipulated the convergence between the direction of an actor's upper limb movement and gaze direction while he attempts to socially interact with the participants observing the scene. We determined the direction of gaze as well as the duration of participants' ocular fixations during the observation of the scene. In Experiment 2, we measured and correlated the effect of the body/gaze manipulation on corticospinal excitability and on the readiness to interact-a disposition to engage in social situations. Eye-tracking data revealed that participants fixated chiefly the actor's head when his hand and gaze directions were divergent. Possibly a strategy to disambiguate the scene. Whereas participants mainly fixated the actor's hand when he performed an interactive request toward the participants. From a neurophysiological point of view, the more participants felt involved in the interaction, the lower was motor preparation in the muscle potentially needed to fulfill the actor's request. We contend that social contexts are more likely to elicit motor preparation compared to non-social ones, and that muscular inhibition is a necessary mechanism in order to prevent unwanted overt reactions during action observation tasks.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / physiology*
  • Cues*
  • Evoked Potentials, Motor
  • Female
  • Fixation, Ocular*
  • Humans
  • Male
  • Pattern Recognition, Visual
  • Transcranial Magnetic Stimulation
  • Young Adult

Grants and funding

This work was supported by Scientific Independence of Young Researchers grant (SIR - N. RBSI141QKX) to LS and by Progetto Strategico, Università di Padova (N. 2010XPMFW4) to UC. The present work was also carried out within the scope of the research program Dipartimenti di Eccellenza (art.1, commi 314-337 legge 232/2016), which was supported by a grant from MIUR to the Department of General Psychology, University of Padua. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.