Petri Toiviainen
University of Jyväskylä, Finland
ptoiviai@jyu.fi
Popular version of paper 1pMU1
"Kinematics and kinetics of music- induced movement"
Presented at 1:00 p.m. on Monday, November 10, 2008
156th ASA Meeting, Miami, FL
When we listen to music, we often move spontaneously with it. It has been suggested that the perception of musical rhythm and pulse is partly a motor phenomenon, and that our movements help us to parse the temporal structure of music.
The temporal structure of music is often hierarchically structured. This means that it contains several pulsations whose periods have integer relationships. For instance, in a waltz we hear the basic pulse and a pulse that is three times slower than the basic pulse. As a result, in a waltz we perceive every third beat as being accented. Similarly, in a march, every second beat is perceived as being weakly accented and every fourth beat strongly accented.
If it is true that we somehow represent the temporal structure of music in our bodily movements, one could assume that these different levels of pulsation can be found in our spontaneous movements to music.
To test this hypothesis, we carried out an experiment, in which we asked our participants to move to a piece of music that was played at five different speeds (tempi). The music was in binary meter, that is, every second beat in it was weakly accented and every fourth beat strongly accented.
To record their movements, we used a motion-capture device consisting of eight infrared cameras that can record the location of reflective markers attached to the participants' body in three dimensions with a spatial accuracy of less than a millimeter and a temporal accuracy of a few milliseconds.
The analysis of the participants' movements revealed that the there are certain kind of movement patterns that are often synchronized with the pulses present in music. Six of the most common ones (so-called eigenmovements) are shown in the animation below.
WATCH ANIMATION: eigenmovements
Moreover, the different levels of pulsation are associated with different movement patters. Most commonly, the movement of the lower arms tend to be synchronized with the one-beat period, the movement of upper arms with the two-beat period, and the swaying of the upper torso with the four-beat period.
Additionally, we investigated the effect of the speed (tempo) of the music on the movements. We found evidence for a resonance phenomenon. In particular, we found that when the tempo of music is such that there are about two beats in a second, the participants tended to move more (see the left panel of figure below) and their movements tended to be better synchronized with the beat (see the right panel of the figure below) than with other tempi.
