PSYCHOLOGICAL SCIENCE

Short Report

Haptically Linked Dyads

Are Two Motor-Control Systems Better Than One?

Kyle Reed,¹ Michael Peshkin,¹  Mitra J. Hartmann,¹ ,² Marcia Grabowecky,³ James Patton,⁴ and Peter M. Vishton⁵

¹Department of Mechanical Engineering, Northwestern University; ²Department of Biomedical Engineering, Northwestern University; ³Department of Psychology, Northwestern University; ⁴Rehabilitation Institute of Chicago, Chicago, Illinois; and ⁵Department of Psychology, College of William and Mary

We report performance of haptically linked dyads on a target-acquisition task, comparing it with that of the same individuals when they performed the task individually. In the dyad condition, a subject’s limb motion responds to the output of two motorcontrol systems—the subject’s own and his or her partner’s-which might be expected to complicate motor planning and efficient task execution. However, task completion times indicated that dyads performed significantly faster than individuals, even though dyad members exerted large task-irrelevant forces in opposition to one another, and despite many participants’perceptions that their partner was an impediment. A much earlier study of teams using a pursuit rotor (Wegner & Zeaman, 1956) found a similar performance increment. Since that study, there has been little research on physically coupled dyads (Sallnas & Zhai, 2003; Shergill, Bays, Frith, & Wolpert, 2003), which we find surprising because performance of motor tasks requiring the physical coordination of two or more people must be an ancient human ability. Bimanual coordination has some similarities to dyadic coordination, but controlling two arms with a single nervous system admits different strategies and constraints (Swinnen & Wenderoth, 2004).

 

Full article