4 - Acceleration & Jerk

Although the third experiment suggests that it is time alone driving this illusion, we wanted to control for the possible influence of acceleration and its derivative - "jerk."  Therefore our final experiment was similar to the third, except here we used three pairs of animations.  The first pair consisted of the original long and short gestures (containing acceleration and jerk), the second pair of smoothed versions of these gestures with equal jerk (differing in their acceleration), and the third pair smoothed versions with equal jerk and acceleration and (differing in velocity).   Because previous research suggests that changes in acceleration are important in the perception of animacy, we wanted to see whether they were important in this paradigm.  However, the results suggest that neither jerk nor acceleration played a meaningful role - visual influence was similar across each of these pairs.  Therefore we can conclude from this series of studies that the illusion is driven primarily by the duration of the post-impact motion. This result is useful for two reasons: (1) it is helpful to musicians interested in understanding how to control such gestures in their performances, and (2) it provides a step towards reconciling this illusion with the theory of optimal integration. Previous: Experiment 3 - Velocity, Distance & Time Return to overview of gesture deconstruction