The more-or-less morphing face illusion: a case of fixation-dependent modulation

Area of Science:

• Visual perception
• Psychophysics
• Cognitive neuroscience

Background:

• Visual illusions demonstrate the active, constructive nature of perception.
• Eye movements play a critical role in how visual information is processed and interpreted.

Purpose of the Study:

• To investigate the influence of eye movements on the perception of changes within a visual morphing sequence.
• To explore a novel visual illusion where perceived morphing extent is modulated by tracking a superimposed dynamic element.

Main Methods:

• Presentation of a face morphing sequence with a superimposed moving dot.
• Participants tracked the moving dot during the morphing sequence.
• Comparison of perceived morphing extent when the dot was moving versus stationary.

Main Results:

• When participants tracked the moving dot, the perceived changes in the morphing sequence appeared minimal.
• When the dot stopped moving, the perceived extent of morphing significantly increased, creating a striking visual illusion.
• This suggests a dynamic interaction between oculomotor activity and the perception of visual transformations.

Conclusions:

• Eye movements, specifically tracking a dynamic element, can suppress the perception of concurrent visual changes.
• The cessation of eye movement tracking leads to an amplified perception of visual transformations, highlighting the role of attention and motion in visual processing.