SAN2020

Visual search is the action of looking for something. While much is known about elements that influence visual search efficacy when one isolated item is searched for, search in real life is more complex, often involving various possible targets kept in memory (hybrid search). While it has long been known that in visual search there is a linear dependence between response times (RT) and visual set sizes (VSS), memory search has been found to increase logarithmically with memory set size (MSS) for sets of up to 100 items. This number, that extend well beyond the limits of working memory, poses a challenge to current theories of visual search. A gap also remains regarding the interplay of inhibitory control, which refers to the ability to effectively subdue thoughts, behaviour, and irrelevant stimuli, in hybrid search strategy and termination. In an online experiment, participants searched for potential targets in images containing different number of stimuli with or without context. Here we show that, in target present trials, regardless of the presence of contextual information and single trial memorisation, the relationship between RT and VSS is linear, while between RT and MSS is logarithmic. In target absent trials, however, we found large differences between context-present and context-absent trials, suggesting a different strategy when the target is absent. In a follow-up experiment, we are currently investigating whether this can be linked to inhibitory control.