Is the motor contagion effect and artifact of eye movements?

Merryn Constable*, Tiffany Lung, John de Grosbois, Luc Tremblay, Jay Pratt, Timothy Welsh

*Corresponding author for this work

Research output: Contribution to conferencePoster


The 'motor contagion' effect manifests when a participant performs one action while simultaneously observing an action performed by another person; observing an incongruent action relative to a congruent action results in an increase in spatial displacement along the orthogonal plane to the participant's intended movement. Motor contagion is often cited as an example of motor interference produced by the activation of motor neurons associated with the observed action that compete with the target action. In the typical motor contagion paradigm, little attention has been given to the complexities of how an individual's eye movement may influence action execution. Indeed, experimenters often instruct their participants to follow the hand of the actor with their eyes while completing the task. It is well known that hands follow eyes; therefore, this instruction could have a large impact on the way motor 'contagion' manifests. Thus, we investigated if concurrently executed eye movements could explain the motor contagion effect. Participants made horizontal arm movements while observing an actor making either vertical (incongruent) or horizontal (congruent) movements under three conditions: no instruction, instruction to maintain fixation on a central cross, or instruction to follow the actor's hand with their eyes. The eye and hand movements of the participants were recorded. Movement variability in the secondary axis was larger in the incongruent than congruent movement conditions only in the 'follow' condition. These data indicate that motor contagion-like effects may be an artifact of simultaneously executed eye movements. We conclude that, at least in this case, an actor's actions are not 'contagious' unless the participant has an existing propensity to follow an actor's actions with their eyes.
Original languageEnglish
Number of pages1
Publication statusPublished - 14 May 2016
Externally publishedYes
EventVSS 2016: The 16th Annual Meeting of Vision Sciences Society - TradeWinds Island Resorts, St. Pete Beach, United States
Duration: 13 May 201618 May 2016


ConferenceVSS 2016: The 16th Annual Meeting of Vision Sciences Society
Country/TerritoryUnited States
CitySt. Pete Beach
Internet address


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