Multiple identified items can be simulatenously tested against the target templates in memory in the hybrid visual and memory search

Most of the search tasks in daily life are a hybrid of visual and memory search. The interplay between the visual and memory search in a hybrid search task can be modeled by a three-stage architecture: 1. visual selection; 2. identification/categorization; 3. target comparison. It is suggested that the visual items are selected sequentially but they can undergo simultaneous identification/categorization, because the pace of visual selection is fast but the pace of object recognition is slow. In the present study, we examined whether multiple identified items can be simultanenously tested against the target templates in memory. In Experiment 1, observers look for either one or two target types in an RSVP stream. The SOA of items is varied to measure a threshold. For search for one target, threshold was 89 ms. When look for either of two targets, threshold is 192 ms. The threshold difference (103 ms) served as a baseline. In Experiment 2, observers look for one or two types of target in a search array. If they had to test each target type separately, we might expect a big jump in the slope of the RT x Set size function, on the order of the baseline measured in Experiment 1. However, the slope difference was only 13 ms/item. These findings suggest that multiple identified items can be simultanenously tested against the target templates in memory, which extends our understanding of the mechanisms of hybrid search.