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Updated: Jul 3, 2026
09:49
Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior
Published on: April 16, 2014
A static geometrical illusion contributes largely to the footsteps illusion
Shoji Sunaga1, Masayuki Sato, Natsuko Arikado
1Department of Visual Communication Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka 815-8540, Japan. sunaga@design.kyushu-u.ac.jp
Perception
|August 9, 2008
Summary
The footsteps illusion, where rectangles appear to change speed, is primarily a static geometrical illusion. Contrary to previous theories, motion detectors play a minimal role in this visual perception phenomenon.
Area of Science:
- Visual Perception
- Psychophysics
- Neuroscience
Background:
- The 'footsteps' illusion describes the apparent speeding up and slowing down of drifting rectangles on a striped background.
- Previous theories proposed this illusion arises from confusion in motion detectors between contrast and velocity signaling.
Purpose of the Study:
- To investigate the role of motion detectors versus static geometrical factors in the footsteps illusion.
- To test Anstis's hypothesis regarding contrast and velocity signaling confusion.
Main Methods:
- Experiment 1 compared the illusion's magnitude in static and dynamic conditions.
- Experiment 2 analyzed the illusion's temporal-frequency tuning.
- Experiment 3 examined the illusion with temporally modulated backgrounds.
Main Results:
- The footsteps illusion was more prominent in static conditions than dynamic ones.
- The illusion showed tuning to low temporal frequencies.
- Modulating a uniform background temporally reduced the illusion's magnitude.
Conclusions:
- The footsteps illusion is predominantly a static geometrical illusion caused by the striped background.
- Motion detectors play a minor role, if any, in generating this visual illusion.
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