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Updated: Jun 27, 2026
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Measuring Attention and Visual Processing Speed by Model-based Analysis of Temporal-order Judgments
Published on: January 23, 2017
Dimension- and space-based intertrial effects in visual pop-out search: modulation by task demands for
Joseph Krummenacher1, Hermann J Müller, Michael Zehetleitner
1Department of Psychology, University of Fribourg, Rue de Faucigny 2, 1700, Fribourg, Switzerland. joseph.krummenacher@unifr.ch
Psychological Research
|December 11, 2008
Summary
Visual search reaction times differ based on task demands. Simple detection shows larger effects of dimension changes and target distance than compound search tasks.
Area of Science:
- Cognitive Psychology
- Visual Perception
- Neuroscience
Background:
- Visual search involves identifying targets among distractors.
- Feature integration theory suggests features are processed separately and then combined.
Purpose of the Study:
- To investigate how task demands modulate intertrial effects in visual search.
- To examine the influence of dimension changes and target distance on reaction times.
Main Methods:
- Two experiments compared reaction times (RTs) in visual search.
- Experiment 1: Simple-detection task (target presence/absence).
- Experiment 2: Compound-search task (detection-irrelevant attribute response).
Main Results:
- Experiment 1 showed significant dimension change (34 ms) and target distance (4 ms/unit) effects.
- Experiment 2 revealed reduced dimension change (11 ms) but increased target distance (11 ms/unit) effects.
- Task complexity modulated attentional focusing and feature integration.
Conclusions:
- Dimension change effects are sensitive to attentional focusing demands.
- Space-based attention influences how feature signals are integrated.
- Task type significantly alters visual search dynamics.
