MEAlagplot graph

[minisharmaa]

Hello Fabian,

I tried to analyse the videos of dyadic interaction recorded online. After keeping in mind all the basic prerequisites of MEA, I extracted the motion time-series of all the videos. I trimmed a few overlapping frames from some videos. finally, I calculated the cross-correlation (winsec=60, incsec=30, lagsec=5) for all the time-series and for the randoms using the ccf function in R studio by using the rMEA package.
when I am plotting the lag plot graph of real vs pseudo dyads by using the MEAlagplot function, the graph is showing % above the random: Video: 100%.

Is it okay to have a 100% relative amount of synchrony and what does it mean? Please help to understand this lag plot graph and also how I can interpret it?

[fabian]

Hi minisharmaa,

I am happy to hear that the analysis worked so far 🙂
Regarding your question:
Is it okay to have a 100% relative amount of synchrony and what does it mean? Please help to understand this lag plot graph and also how I can interpret it?

The lagplot provides both a graphical as well as a numerical estimation of when and for which duration your original data is different from randomness. If your original data did not contain any signs of substantial synchrony, the real data would be similar or very close to the random data (pseudosynchrony).
Your finding of 100% above random means that for the chosen lagsize (lagsec=5), the real data is always higher than the pseudodata. This is “normal” and means that for this extension of time ±5sec, real synchrony goes beyond pseudosynchrony.
I suggest you try out the following: If you increase lagsec (e.g. to 10ec), you will probably see that your real data will cross the pseudodata at some point in time. The crossing-point may be regarded as the limit of the social present.

You can find more information in the paper on rMEA:
Kleinbub, J. R., & Ramseyer, F. T. (2021). Rmea: An r package to assess nonverbal synchronization in motion energy analysis time-series. Psychotherapy Research, 31(6), 817-830. doi:10.1080/10503307.2020.1844334
And in the paper on the social present:
Tschacher, W., Ramseyer, F., & Koole, S. L. (2018). Sharing the now in the social present: Duration of nonverbal synchrony is linked with personality. Journal of Personality, 86(2), 129-138. doi:10.1111/jopy.12298

Good luck and cheers from Bern,
Fabian

[Author]

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