Assessing The Effect of Stimuli Complexity in Web-Based Visual Foraging

The visual foraging task investigates observer visual search behavior in respect of multiple targets. Across previous studies, abstract stimuli are commonly used to explore foraging behaviors. To fully explore visual search as it occurs in real-world environments, it was of interest to substitute abstract stimuli for ecologically valid stimuli in a foraging task. The present study investigated the effects of stimuli complexity on observer foraging performance using ecologically valid foraging stimuli. Participants (N = 221) completed a 14-block web-based foraging task on their own devices. The stimuli were categorized into control sets (simple shapes with 1 feature layer, and conjunctive shapes with 2 feature layers) and experimental sets (stop signs and yield signs with 1 to 3 layers of features). Each block contained pages with 6 targets and 6 distractors. Participants viewed a target example commencing an exhaustive search. They were instructed to complete as may pages as possible per block (45 seconds). Foraging performance was assessed using mean inter-target time (ITT), where higher ITT suggested less efficient foraging performance. Linear multi-level models showed increased ITT with stimuli complexity, except in the three-layer stop sign condition. Observers using smaller screens foraged faster than those on larger screens. The variation of ITT between blocks for each stimuli type was minimal, suggesting that individuals maintained consistent foraging speeds within each stimulus category. However, greater variation in ITT within blocks was observed for the experimental stimuli, suggesting more variability in foraging performance in the experimental conditions. These findings are consistent with the theory that complex stimuli prolong search times and contribute to research on the "pop-out" search effect. Further, this research sheds light on the impacts of device differences on task performance. Overall, this study emphasizes the importance of considering the ecological context in understanding observer foraging performance.