ABSTRACT
Background: Incidental findings are items of visual search that are potentially of significance, but were not the main object of the initial search. They have been previously widely discussed in the field of radiology. However, the underlying perceptual mechanisms of such phenomenon are still unclear. Objective: The current study aims to examine incidental findings in different paradigms of visual search in order to reveal their primary perceptual aspects. Design: Two behavioral visual search experiments were conducted. The mixed hybrid search task model was used in the first experiment, while the subsequent search miss effect was employed in the second experiment. The task was to find targets among distractors, according to given instructions. Stimuli material consisted of images of real-life objects that were randomly distributed across the screen for each trial. Results: Accuracy and reaction time of the participants were analyzed in both experiments. Similar effects were observed for both parameters. Specific targets in the first experiment and typical targets in the second experiment were found significantly faster and more accurately in comparison to categorical and atypical targets. Moreover, this tendency did not depend on the order of target identification. Hence, the prevalence of the targets was revealed to be the primary factor in the case of incidental findings. Conclusion: The study revealed the emergence of incidental findings in both experiments. Typical or specific targets were detected significantly more accurately, compared to atypical or categorical targets. Subsequent search misses were not detected, suggesting that target prevalence could be a crucial factor that is specific for incidental findings.
ABSTRACT
Subsequent search misses (SSM) refer to the decrease in accuracy of second target detection in dual-target visual search. One of the theoretical explanations of SSM errors is similarity bias - the tendency to search for similar targets and to miss the dissimilar ones. The current study focuses on both perceptual and categorical similarity and their individual roles in SSM. Five experiments investigated the role of perceptual and categorical similarity in subsequent search misses, wherein perceptual and categorical similarities were manipulated separately, and task relevance was controlled. The role of both perceptual and categorical similarity was revealed, however, the categorical similarity had greater impact on second target detection. The findings of this research suggest the revision of the traditional perceptual set hypothesis that mainly focuses on perceptual target similarity in multiple target visual search.
