Abstract
Various studies have demonstrated enhanced performance when visual information is presented across both visual hemifields rather than in a single hemifield (the bilateral advantage). For example, Alvarez and Cavanagh (2005) reported that observers were able to track twice as many moving visual stimuli when the tracked items were presented bilaterally rather than unilaterally, suggesting that independent resources enable tracking in the two visual fields. Motivated by similarities in the apparent capacity and neural substrates that mediate tracking and visual working memory (WM), the present work examined whether or not a bilateral advantage also arises during storage in visual WM. Using a recall procedure to measure the precision with which orientations were held in WM, we found a reliable bilateral advantage; recall error was smaller with bilateral sample displays than with unilateral displays. To test whether these results were due to differences in encoding quality, we measured recall error with simultaneous and sequential stimulus displays. The bilateral advantage was just as large with sequential displays, showing that this effect was not due to encoding differences. Thus, we conclude that the bilateral advantage extends beyond the initial acquisition of visual information, such that mnemonic resolution is reliably enhanced by bilateral presentations of the to-be-stored items.