directionality by using MEA

[minisharmaa]

Hello,

Is there any way that we can infer the directionality of the two-time series by using MEA? Also if we can go beyond the pairwise approach and calculate the synchrony for a group?

Thank you

[fabian]

Hi,

Yes – this is quite straightforward if you use rMEA
(https://cran.r-project.org/web/packages/rMEA/index.html)
The MEAccf function provides you with a value for overall synchrony (all_lags) and values for either subject1_leading (s1Name_leading) or subject2_leading (s2Name_leading).

If you want to calculate synchrony for more than 2 subjects, you need a different approach, or you could calculate synchrony for all possible pairs.
Best, Fabian

[minisharmaa]

Hi,
Thank you for your response. I understand how we can calculate the directionality. Sorry, I was not clear before, I am trying MEA in the free mirroring experiment. we instruct people to mirror each other’s hand movements and then with the help of MEA we calculate lead/lag or synchrony between them. but the problem we are facing is it does not matter if the two people are exactly mirroring each other or not even if they are doing any random hand movement together (not mirrored) MEA calculates it as synchrony.
I am trying to follow one paper in which they have calculated the Z non-absolute value and refer to positive values as in-phase synchronisation and negative values as anti-phase synchronisation-
Tschacher, W., and Meier, D. (2020). Physiological synchrony in psychotherapy dyads.Psychotherapy Research. 30, 558-573. https://doi.org/10.10503307.2019.1612114.
Also, I am reading your paper in which you have calculated the speed of the movement. it would be really helpful if you can guide how I can calculate the speed of the hand movements of the participants by using MEA.
Video-based quantification of body movement during social interaction indicates the severity of negative symptoms in patients with schizophrenia. doi:10.1016/j.schres.2010.03.032.

Thank you for your help!!

[fabian]

You are right: The qualitative aspect of movement cannot be measured with MEA (see: Ramseyer, F. T. (2020). Motion Energy Analysis (MEA). A Primer on the Assessment of Motion From Video. Journal of Counseling Psychology, 67(4), 536-549. https://doi.org/10.1037/cou0000407)

For the triadic aspect, these papers may also help:
Dale, R., Bryant, G. A., Manson, J. H., & Gervais, M. M. (2020). Body Synchrony in Triadic Interaction. Royal Society open science, 7(9), 200095. https://doi.org/10.1098/rsos.200095
Fujiwara, K. (2016). Triadic Synchrony: Application of Multiple Wavelet Coherence to a Small Group Conversation. AM, 07(14), 1477-1483. https://doi.org/10.4236/am.2016.714126

The other aspects (speed, duration, max, etc.) are on the individual level and they can be derived from the time-series generated by MEA. (this was done in an older script in SAS, but I suggest to implement it in R according to your requirements).

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