Abstract
In Hybrid Search (HS), observers are required to memorize potential targets and then identify their presence among various distractors. A hallmark of visual search is a linear dependence between response times (RTs) and visual set sizes (VSS), while memory search shows a logarithmic increase with the number of items in the memory set size (MSS). This has been interpreted on the basis of an efficient neural representation of remembered items, partially overcoming working memory (WM) limitations. However, the relationship between WM and search efficiency remains controversial. Moreover, although context plays a major role in real-world search, HS tasks have mostly used isolated stimuli. Here, we sought to examine the role of visual WM capacity in an HS task where potential targets changed in every trial. We also investigated the effects of contextual information in HS performance and studied the role of inhibitory control (IC) in search termination. In online experiments, 110 participants performed a HS task, a change-detection task to assess visual WM, and a go/no-go task. Concurrent EEG and eye movement recordings were measured in a separate sample to investigate the interplay between search, WM, and neural oscillations. We show that, in target-present trials, the main hallmarks of HS remain present. Consistent with recent findings, contextual information facilitated visual search (Vo & Wolfe, 2016) but not memory search (Boettcher et al., 2018). Individual differences in visual WM did not predict HS performance. In target-absent trials, context played a major role and HS performance could be predicted by IC, showing a direct link between inhibition and search termination. Finally, we used the behavioural findings to study neurophysiological signatures of HS. Whereas this study adds ecological validity to well established RT signatures of HS, it also provides insights into the effects of WM and context on HS efficiency and search termination.