Detecting Deception in Movement: The Case of the Side-Step in Rugby

Sebastien Brault, Benoit Bideau, Richard Kulpa, Cathy M. Craig

Research output: Contribution to journalArticlepeer-review

101 Citations (Scopus)
493 Downloads (Pure)


Although coordinated patterns of body movement can be used to communicate action intention, they can also be used to deceive. Often known as deceptive movements, these unpredictable patterns of body movement can give a competitive advantage to an attacker when trying to outwit a defender. In this particular study, we immersed novice and expert rugby players in an interactive virtual rugby environment to understand how the dynamics of deceptive body movement influence a defending player’s decisions about how and when to act. When asked to judge final running direction, expert players who were found to tune into prospective tau-based information specified in the dynamics of ‘honest’ movement signals (Centre of Mass), performed significantly better than novices who tuned into the dynamics of ‘deceptive’ movement signals (upper trunk yaw and out-foot placement) (p<.001). These findings were further corroborated in a second experiment where players were able to move as if to intercept or ‘tackle’ the virtual attacker. An analysis of action responses showed that experts waited significantly longer before initiating movement (p<.001). By waiting longer and picking up more information that would inform about future running direction these experts made significantly fewer errors (p<.05). In this paper we not only present a mathematical model that describes how deception in body-based movement is detected, but we also show how perceptual expertise is manifested in action expertise. We conclude that being able to tune into the ‘honest’ information specifying true running action intention gives a strong competitive advantage.
Original languageEnglish
Article numbere37494
Number of pages13
JournalPLoS ONE
Issue number6
Publication statusPublished - 11 Jun 2012


  • Deceptive movement, informational invariants, tau-coupling, rugby

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)


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  • Université de Rennes

    Cathy Craig (Supervisor)

    05 Sept 200830 Jun 2009

    Activity: Visiting an external institution typesResearch and Teaching at External Organisation

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