Asynchronized exposure: How giving some stimuli a head start influence attention

Several theories have been proposed on how Visual Short-Term Memory (VSTM) encode stimuli (e.g., Bundesen, 1987; Schurgin et al., 2020). Theory of Visual Attention (Bundesen, 1990) assumes that attention functions as a race into a limited VSTM. Here we examine how two different classes of stimuli are processed if one is presented with a slight head start. This relationship was examined in a whole report experiment where we presented eight stimuli in a memory array. Three conditions were implemented consisting of either letters, pictures, or a mixture of letters and pictures. In two additional critical conditions we presented mixed stimuli, providing a 50 ms onset advantage to either pictures or letters. The onset was controlled with pre- and post-masking of the memory array. Participants were encouraged in all conditions to report as many stimuli as possible regardless of type. Previously research have demonstrated a VSTM advantage in capacity for letters (Sørensen & Kyllingsbæk, 2012; Dall et al., 2016). Therefore, participants are expected to have letter advantage in processing, even when pictures are provided a head start in onset. By varying exposure durations (5-200 ms) we explore the processing race into VSTM and find on synchronises trials that participants remember more pictures than letters at lower exposure durations. However, at higher exposure durations participants demonstrate a letter advantage. This seems to suggest that pictures have an early processing advantage which is progressively reduced on the later exposure rates.