Right Hemisphere Memory Bias Does Not Extend to Involuntary Memories for Negative Scenes

Attention is unequally distributed across the visual field. Due to greater right than left hemisphere activation for visuospatial attention, people attend slightly more to the left than the right side. As a result, people voluntarily remember visual stimuli better when it first appears in the left than the right visual field. But does this effect—termed a right hemisphere memory bias—also enhance involuntary memory? We manipulated the presentation location of 100 highly negative images (chosen to increase the likelihood that participants would experience any involuntary memories) in three conditions: predominantly leftward (right hemisphere bias), predominantly rightward (left hemisphere bias), or equally in both visual fields (bilateral). We measured subsequent involuntary memories immediately and for 3 days after encoding. Contrary to predictions, biased hemispheric processing did not affect short- or long-term involuntary memory frequency or duration. Future research should measure hemispheric differences at retrieval, rather than just encoding.