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Updated: Jul 28, 2026
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Investigating the Deployment of Visual Attention Before Accurate and Averaging Saccades via Eye Tracking and Assessment of Visual Sensitivity
Published on: March 18, 2019
Stimulus control of visual fixation duration in a single saccade paradigm
1Department of Cognitive Psychology, Vrije Universiteit, Amsterdam, The Netherlands.
Acta Psychologica
|August 26, 1998
Summary
Fixation time of the left stimulus (SL) is not preprogrammed but triggered by perceptual identification completion. This suggests SL fixation time is a valid measure for reaction time uncontaminated by decision.
Area of Science:
- Cognitive psychology
- Neuroscience
- Visual perception
Background:
- The fixation time of the left stimulus (SL) in a visual search task has been proposed as a measure of perceptual identification.
- This measure, termed the (d)-reaction, assumes saccades are triggered upon perceptual completion.
Purpose of the Study:
- To investigate whether SL fixation time is preprogrammed or triggered by perceptual completion.
- To validate the use of SL fixation time as a measure of perceptual identification.
Main Methods:
- Two experiments were conducted manipulating stimulus presentation timing and quality.
- Experiment 1: Delayed presentation of SL with fixed or variable intervals.
- Experiment 2: Varied stimulus quality of SL within and between trial blocks.
Main Results:
- Results from both experiments indicate that SL fixation time is not preprogrammed.
- Data support the hypothesis that saccades are initiated upon completion of perceptual processing.
- SL fixation time is a reliable indicator of perceptual identification.
Conclusions:
- The fixation time of the left stimulus (SL) in this paradigm is not preprogrammed.
- The saccade to the right stimulus (SR) is triggered by the completion of perceptual identification of SL.
- SL fixation time is a viable candidate for the (d)-reaction, measuring perceptual identification uncontaminated by decision processes.
