Mixing it up: Intermixed and blocked visual search tasks produce similar results

Area of Science:

• Cognitive Psychology
• Visual Perception
• Human Factors

Background:

• Traditional visual search research relies on blocked trials, presenting the same target and distractors repeatedly.
• Real-world visual search involves diverse and rapidly changing targets and distractors.
• Existing models of visual search mechanisms are often based on blocked-trial data.

Purpose of the Study:

• To investigate whether visual search behavior differs between blocked and mixed trial conditions.
• To determine the generalizability of search rules derived from blocked trials to more realistic, mixed search scenarios.
• To test the validity of current visual search models under varied task demands.

Main Methods:

• Five experiments compared blocked and mixed visual search conditions.
• Tasks included feature search, varied distractors with a constant target, and constant distractors with varied targets.
• Participants performed tasks individually or chose their task on each trial.

Main Results:

• No qualitative differences in visual search behavior were observed between blocked and mixed conditions across all experiments.
• Search performance metrics, such as Reaction Time × Set Size functions, remained consistent regardless of trial arrangement.
• The findings indicate that search strategies are robust to changes in task predictability.

Conclusions:

• Rules of visual search derived from blocked trials appear to generalize well to mixed-task environments.
• Current understanding of visual search mechanisms is supported by the consistency of behavior across different experimental designs.
• Simple adaptive models of search termination may require refinement to account for the observed robustness of search behavior.