Time course of target recognition in visual search.

Area of Science:

• Cognitive Psychology
• Neuroscience
• Visual Perception

Background:

• Visual search involves eye movements to locate targets within a scene.
• Target identification is assumed to occur during eye fixations.
• Limited fixation durations raise questions about whether identification happens *before* the final fixation.

Purpose of the Study:

• To experimentally verify if target recognition can occur extrafoveally (before direct eye fixation).
• To investigate the role of the final eye fixation in visual search accuracy and confidence.

Main Methods:

• Employed a gaze-contingent, real-time technique to control search display duration.
• Subjects performed a visual search task for oriented colored bars.
• Search was prematurely terminated shortly after target fixation, and subjects identified the target location.

Main Results:

• Subjects could identify the target location with less than 10 ms of fixation.
• Extended target fixation did not enhance performance but increased confidence ratings.
• Immobility of eyes prevented task performance, highlighting the necessity of eye movements.

Conclusions:

• Target information can be acquired at least one fixation prior to the final one during conjunction search.
• The final eye fixation primarily serves to increase subjective confidence rather than objective accuracy.
• This suggests a dissociation between performance accuracy and confidence judgments in visual search.