The control of fixation duration in visual search

Area of Science:

• Cognitive Psychology
• Visual Perception
• Human-Computer Interaction

Background:

• Understanding how visual search behavior is modulated by internal knowledge and external environmental cues is crucial for explaining human visual processing.
• Fixation durations during visual search are influenced by various factors, including the type of search (bottom-up vs. knowledge-driven) and the availability of peripheral information.

Purpose of the Study:

• To investigate how fixation durations are affected when observers voluntarily use visual environmental information to guide saccades during target search.
• To examine the interplay between search type, peripheral preview, and saccade accuracy on fixation durations.

Main Methods:

• Experiments utilized direction-coded displays to present visual search tasks.
• Fixation durations were recorded for both correctly and incorrectly directed saccades.
• Peripheral preview was manipulated, including conditions with ample access and a gaze-contingent moving window.
• Fixation control was modeled using sigmoid functions.

Main Results:

• During image-driven (bottom-up) search, fixation durations for correct and incorrect saccades were similar.
• In knowledge-driven search, ample peripheral preview led to shorter fixation durations preceding correct saccades compared to incorrect ones.
• Conversely, when peripheral preview was constrained by a gaze-contingent moving window during knowledge-driven search, fixation durations preceding correct saccades were longer than those preceding incorrect saccades.

Conclusions:

• The relationship between saccade accuracy and fixation duration in visual search is dependent on the type of search and the extent of peripheral information available.
• Peripheral preview significantly modulates fixation control strategies, particularly in knowledge-driven visual search.
• Sigmoid functions effectively model the observed fixation control mechanisms.