Demonstrations for Manuscript

 

The Beep-Speed Illusion: Non-Spatial Tones Increase Perceived Speed of Visual Objects

 

1. This is a basic demo of the audio-visual version of the illusion. Your task is to decide whether the left or the right object appears to move at a higher speed.

In this demonstration video, both objects moved at the same speed. For most observers, however, the object that is synchronized with the tone, appears to move faster (response sequence: left – right – right – right – right – left). In the actual experiments, we varied the speed of the purely visual object, and obtained psychometric functions of the response patterns which signaled that the purely visual object needed to move faster than the audio-visually synchronized object to appear moving at the same speed (i.e., a shift in the point of subjective equality).

 

 

2. We observed a similar illusion when we guided attention to one of the moving objects with a visual cue (a color change of the moving object).

This finding suggests that the audio-visually synchronized object attracts attention which in return elicits the illusory increase in object speed.

 

 

3. Pure temporal coincidence (i.e., a color change of the surrounding frame) is not sufficient to trigger an illusory increase in perceived object speed.

This finding suggests that audio-visual coincidences are capable of guiding attention to the synchronized object whereas purely visual coincidences are not.