Asymmetrical control of fixation durations in scene viewing

Area of Science:

• Cognitive Psychology
• Visual Perception
• Computational Neuroscience

Background:

• Fixation durations in naturalistic scene viewing are influenced by processing difficulties, potentially prolonging viewing time.
• Previous research in visual search and reading suggested uni-directional control of fixation durations, primarily slowing down.
• The role of processing facilitation in modulating fixation durations during scene viewing remained unclear.

Purpose of the Study:

• To investigate whether processing facilitation can decrease fixation durations in naturalistic scene viewing.
• To determine if fixation duration control in scene viewing is uni-directional (only slowing down) or bi-directional (slowing down and speeding up).

Main Methods:

• Two experiments utilized a saccade-contingent display change method.
• Stimulus luminance was manipulated (decreased or increased) during critical fixations to induce processing difficulty or facilitation.
• Fixation durations were measured and analyzed in response to these luminance changes.

Main Results:

• Degrading the visual stimulus by decreasing luminance led to an immediate increase in fixation durations.
• Clarifying the visual stimulus by increasing luminance did not result in a comparable decrease in fixation durations.
• The observed asymmetric response suggests that fixation duration control is not bi-directional.

Conclusions:

• Fixation duration control in naturalistic scene viewing appears to be asymmetric.
• This asymmetry mirrors findings in visual search and reading, indicating a consistent pattern across different visual tasks.
• The visual system prioritizes prolonged fixation when encountering processing difficulties rather than shortening fixation when processing is facilitated.