The bizarreness effect and visual imagery : no impact of concurrent visuo-spatial distractor tasks indicates little role for visual imagery

Ancient as well as modern writers have promoted the idea that bizarre images enhance memory. Research has documented bizarreness effects, with one standard technique finding that sentences describing unusual, implausible, or bizarre scenarios are better remembered than sentences describing plausible, every day, or common scenarios. Not surprisingly, this effect is often attributed to visual imagery, and the effect often referred to as the bizarre imagery effect. But the role of imagery has been disputed even as research has found it difficult to clearly distinguish the effects of imagery from other possible bases for the bizarreness advantage. The current experiments assessed the visual-imagery hypothesis by disrupting visual imagery processes during encoding, which should reduce the bizarreness effect if it is indeed due to imagery. Specifically, one group carried out a concurrent task that selectively disrupted visual working memory (and visual imagery) during the encoding of sentences; a control group encoded the sentences without distraction. Across four experiments, the distractor task was dynamic visual noise, the spatial tapping task, and a visual span task. Each experiment found a robust bizarreness effect that was never reduced by visuospatial distraction. Combined, meta-analytic, and Bayesian analyses concurred with the results of the individual experiments. The results indicate little role for visual imagery in the bizarreness effect.