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Updated: Aug 15, 2026
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Creating Dynamic Images of Short-lived Dopamine Fluctuations with lp-ntPET: Dopamine Movies of Cigarette Smoking
Published on: August 6, 2013
Illusory smoke and dazzling fog
L Tommasi1, D Zavagno, G Vallortigara
1Department of General Psychology, University of Padova, Via Venezia 8, 35131 Padova, Italy. ltommasi@psico.unipd.it
Psychological Research
|August 17, 2001
Summary
Rotating a grey-shaded ellipse creates illusions of smoke or fog. This visual effect depends on background contrast and requires movement, not just static images, for a compelling experience.
Area of Science:
- Visual perception
- Illusory motion
- Geometric optics
Background:
- A rotating flat ellipse typically appears as a tilting circular disc.
- Existing research focuses on the perceived 3D motion of rotating ellipses.
Purpose of the Study:
- To investigate novel visual illusions generated by rotating grey-shaded ellipses.
- To determine the conditions necessary for these illusions to occur.
Main Methods:
- Presenting grey-shaded ellipses on contrasting backgrounds (white/black).
- Observing participant responses to static and dynamic stimuli.
- Analyzing the role of luminance contrast and relative motion.
Main Results:
- A compelling illusion of "smoke" or "fog" was observed, depending on background.
- The "fog" effect vanished with luminance contrast along the ellipse perimeter.
- Relative movement between ellipse contours and shading was crucial; static conditions yielded limited effects.
Conclusions:
- Grey-shaded ellipses can induce illusory motion akin to smoke or fog.
- The illusion is dependent on specific luminance and motion dynamics.
- Perceived depth is not essential for this particular visual phenomenon.
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