The Müller-Lyer line-length task interpreted as a conflict paradigm: A chronometric study and a diffusion account

Area of Science:

• Cognitive Psychology
• Visual Perception
• Computational Neuroscience

Background:

• The Müller-Lyer illusion is a classical example of geometrical-optical illusions.
• Existing interpretations often focus on static structural mechanisms.
• Perceptual conflict paradigms offer a framework for understanding such illusions.

Purpose of the Study:

• To interpret the Müller-Lyer illusion within a conflict paradigm framework.
• To develop and test a diffusion model explaining decision-making in the illusion.
• To integrate structural and strategic mechanisms contributing to the illusion.

Main Methods:

• Eight practiced observers compared line lengths in line-arrow combinations.
• Stimulus attributes (line length, arrow orientation) were varied unpredictably.
• A diffusion model was fitted to psychometric and chronometric data.

Main Results:

• The diffusion model quantitatively accounted for decision speed and accuracy.
• Task-irrelevant arrow orientation influenced drift and response boundaries.
• Arrow-congruent responses were more frequent at faster reaction times.

Conclusions:

• The proposed diffusion model provides a process-related account of the Müller-Lyer illusion.
• The model integrates structural and strategic factors underlying the illusion.
• This approach aligns with viewing optical illusions as manifestations of perceptual conflict resolution.