Working memory contents influence binocular rivalry

Numerous studies have investigated how holding a visual object in memory affects the processing time of subsequently presented objects. However, whether working memory contents can bias the interpretation of ambiguous stimuli as in binocular rivalry is still an unexplored issue. We presented seven participants with images of faces, houses, or cars for 500 ms and asked them to memorize them for a delayed match to sample test. Novel memory items were presented in each trial: pilot experiments helped us identify 240 different memory items that were accurately recognized in less than 80% of cases for all stimulus categories (74.2% correct on average). After a 3 s ISI, a classical face-house rivalrous display was presented for 15 s until the memory test. The two rivalrous stimuli were equal in mean luminance and their contrast levels were set individually for each participant to yield approximately even dominance periods. Periods of relative dominance for the face lasted for 48.8% and 44.8% of the time when holding in memory a face and a house respectively (p=0.014). This result suggests that working memory contents can bias the competition between conflicting stimuli in a top-down fashion.