Can Humans Learn How to Minimize Unintended Interpersonal Coordination?

1. Can Humans Learn How to Minimize Unintended Interpersonal Coordination? L. MARIN1, J. ISSARTEL1.2 & M. CADOPI1 1. Motor Efficiency and Deficiency Laboratory, University Montpellier 1, Montpellier, France 2. Sonic Arts Research Center, Queen’s University, Belfast, Northern Ireland

2. Coordination between two (or more) people Present all the time and in every situation Requires perceptual contact (tactile, visual, auditory…) Characteristics of interpersonal coordination between humans Hands clapping Ex: applause tends to be in-phase (Neda 2000).

3. Interpersonal coordination can be intentional Intentional interpersonal coordination

4. Unintended interpersonal coordination However, in our day-to-day lives, interpersonal coordination is mostly unintentional

5. Unintended interpersonal coordination: Experimental evidence 1 (Schmidt & O’Brien, 1997) Instructions to participants: Swing a pendulum at their preferred frequency 2 conditions: - with - without the other participant’s moves in sight Results: with the other participant’s movements in sight in phase and anti-phase coordination emerge Consequently : Participants coordinate together even if coordination is not the goal of the situation (or the instructions)

6. Unintended interpersonal coordination: Experimental evidence 2 (Issartel, Marin & Cadopi, 2007) In a recent experiment authors explicitly asked participants to not coordinate their movements with the other participant? Instructions to participants: move their arms however they want 2 conditions: - alone - with someone to move as if they were alone Results When alone:low correlation between participants= 0.37 When front of someone: correlation = 0.66 Consequently: Unintentional synchrony emerges even when instructions explicitly specify to not synchronize with the other participant

7. Unintended Interpersonal Coordination: Conclusion The emergent phenomenon of coordination is so powerful that humans cannot avoid an unintended dyadic motor coordination This consequence is an illustration of the spontaneous process that underlies human interpersonal coordination

8. Unintended Interpersonal Coordination: Goal of this study But are humans able to change their natural process ? Can we learn how to minimize the unintended phenomenon of interpersonal coordination ? In this study we are interested in investigating: Whether humans CAN adapt new “ways” of dealing with this spontaneous process.

9. Unintended Interpersonal Coordination: Hypothesis We hypothesize that expert dancers can be a representative example of humans that are able to adapt new “ways” of dealing with this spontaneous process. We predict that expert contemporary dancers are able to not coordinate with someoneif we ask them to do so because they are used to acting without taking into account the moves of other dancers.

10. Method: Participants and task • 12 pairs of participants: • 6 pairs of expert dancers • 6 pairs of non dancers - Right elbows were put on the table Task • to freely move their right forearm in the vertical plane • No instructions about frequency or amplitude Led to an improvisational situation

11. Interpersonal coordination and dance improvisation Expert contemporary dancers are often involved in an improvisational dance situation An improvisational dance taskis a very rich situation from a dynamical point of view: • Movements are not planned - Movements are made from moment to moment - Improvisation is made straight away Emergence of movements An improvisational task reveals dancer’s individual properties (motor signature) which are manifested as preferred frequencies

12. 1 2 Method: 2 experimental conditions • Condition Alone = Each participant moved his/her arm alone (control condition) • Condition Paired= participants sat front each other. They were instructed to not take into account the movements of the other participant 6 trials in each condition Analyses were performed on theangle between the forearm and the arm

13. Method: Wavelet and Cross-wavelet transform Method The wavelet transform (WT) Precisely estimates the frequencies of the participants’ movements throughout the time (Issartel et al., 2006) The Cross-Wavelet Transform (CWT) Interaction between two signals Precisely estimates the common frequencies between participants’ movements throughout the time (Issartel et al., 2006)

14. Method: Data analysis and variables Before analyzing interpersonal interaction 1) Motor signature analysis Individual properties Motor Signature Wavelet Analysis Comparison inter trial and inter condition (reproducibility): - Number of frequency occurrences - Distribution of the WT spectrum indicates frequencies distribution of the entire spectrum

15. Method: Data analysis and variables 2) Interpersonal interaction analysis Cross-wavelet Analysis Common frequencies between two signals Comparison inter group: - Distribution of the Cross-WT spectrum Compares frequencies distribution between 2 participants

16. Results: Visual analysis of the motor signature Each participant maintains the same frequency range Illustration of an individual motor signature

17. Results: Quantitative analysis of the motor signature Comparison inter trialfor each participant Similar number of frequencies Similar distribution of frequencies Motor Signature for each participant Comparison inter conditionfor each participant Similar number of frequencies Similar distribution of frequencies Motor Signature for each participant Even if participants can freely move without frequency and amplitude constraints, dancers’ and non-dancers’ movements are limited to a preferential range of frequencies

18. Results: Comparison of interpersonal interaction Comparison inter group Non-dancers • In Alone condition:low (virtual) correlation of commonfrequencieswithin pairs of participants, R2= 0.37 • In Paired condition:correlation of common frequencieswithin pairs of participants, R2= 0.66 Dancers No statistical differences between Alone and Paired condition Contrary to non-dancers, there is no emergence of unintentional interaction for expert dancers

19. Discussion: Interacting with someone does not change the individual motor signature There is a strong hold of the motor signature The most significant finding is that dancers can intentionally not be coordinated with the other dancer whereas the non-dancers cannot During long hours of rehearsal expert dancers have learned to perform their own specific choreography without taking into account the environment around them(i.e., other dancers)

20. Conclusion: Even if all humans seem to use the same processes to synchronize (Schmidt & O’Brien, 1997) The example of expert dancers shows that they did not follow the same processes as non-expert dancers - they found new ways of dealing with this synchronization thus demonstrating that people can learn how to change the way they typically synchronize with someone. This is an illustration of the wonderful capacity humans have for adaptation. This level of sophistication and complexity is unique to the human species, and we have yet to see these kinds of developments in robots or machines.

21. Thank you For your attention