Visual appearance modulates motor control in social interactions

Stephan De La Rosa,Tobias Meilinger,Stephan Streuber,Aurelie Saulton,Laura Fademrecht,M Alejandra Quiros-Ramirez,Heinrich Bülthoff,Isabelle Bülthoff,Rouwen Cañal-Bruland

doi:10.1016/j.actpsy.2020.103168

Abstract

The goal of new adaptive technologies is to allow humans to interact with technical devices, such as robots, in natural ways akin to human interaction. Essential for achieving this goal, is the understanding of the factors that support natural interaction. Here, we examined whether human motor control is linked to the visual appearance of the interaction partner. Motor control theories consider kinematic-related information but not visual appearance as important for the control of motor movements (Flash & Hogan, 1985; Harris & Wolpert, 1998; Viviani & Terzuolo, 1982). We investigated the sensitivity of motor control to visual appearance during the execution of a social interaction, i.e. a high-five. In a novel mixed reality setup participants executed a high-five with a three-dimensional life-size human- or a robot-looking avatar. Our results demonstrate that movement trajectories and adjustments to perturbations depended on the visual appearance of the avatar despite both avatars carrying out identical movements. Moreover, two well-known motor theories (minimum jerk, two-thirds power law) better predict robot than human interaction trajectories. The dependence of motor control on the human likeness of the interaction partner suggests that different motor control principles might be at work in object and human directed interactions.

Highlights

Shaking a friend's hand or picking up a glass for drinking are two examples of humans commonly interacting with their physical and social environment in everyday life
Researchers have suggested that object and social interactions might rely on common motor principles based on theoretical considerations (Wolpert et al, 2003; Wolpert & Flanagan, 2001)
In contrast to the prediction that visual appearance does not influence motor control, we found that the arm movement depended on the visual appearance of the avatar along all spatial axes

Summary

Introduction

Shaking a friend's hand or picking up a glass for drinking are two examples of humans commonly interacting with their physical and social environment in everyday life. To date it remains largely unknown whether motor actions directed towards the physical (e.g. objects) and social (e.g., other people) environment rely on the same motor principles. Little is known about motor control in such interactive scenarios, where participants' movements are not restricted To this end, we examined whether motor control processes differ when humans interact (i.e. high-fived) with a social (i.e. human) and object (i.e. a robot) environment

Methods

Results

Conclusion