Motiongrams of rhythmic chimpanzee swaying

I came across a very interesting study on the Rhythmic swaying induced by sound in chimpanzees. The authors have shared the videos recorded in the study (Open Research is great!), so I was eager to try out some analyses with the Musical Gestures Toolbox for Matlab.

Here is an example of one of the videos from the collection:

The video quality is not very good, so I had my doubts about what I could find. It is particularly challenging that the camera is moving slightly over time. There is also a part where the camera zooms in towards the end. A good rule of thumb is to always use a tripod and no zoom/pan/tilt when recording video for analysis.

Still, I managed to create a couple of interesting visualizations. Here I include two motiongrams, one horizontal and one vertical:

This horizontal motiongram shows the sideways motion of the monkey. Time runs from left to right.
This vertical motiongram reveals the sideways motion of the monkey. Time runs from top to bottom.

Despite the poor input quality, I was happy to see that the motiongrams are quite illustrative of what we see in the video. They clearly reveal the rhythmic pattern of the monkey’s motion. It would have been interesting to have some longer recordings to do some more detailed analysis of correspondences between sound and motion!

If you are interested in making such visualisations yourself, have a look at our collection of tools in the Musical Gestures Toolbox.

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Alexander Refsum Jensenius is a music researcher and research musician living in Oslo, Norway.