The Fuzzy Attentional Boost: Novelty-Linked Arousal Supports Gist Memory

The attentional boost effect (ABE) occurs when target detection in a primary task stream enhances memory for coincident but task-irrelevant information. However, it remains unclear whether this “boost” represents a true enhancement of memory fidelity or simply a biased recognition response. To address this, we developed a novel category-selective ABE paradigm that enables us to dissociate memory sensitivity from response bias. In Phase 1, participants categorized unique images from three semantically distinct object categories. In Phase 2, participants performed an auditory target detection task for infrequent oddball tones while object images were incidentally presented. Critically, the oddball tones were selectively paired with images belonging to only one of the object categories (“Target”). While we replicated the classic ABE finding of enhanced hit rate for Target versus Nontarget images, follow-up analyses using Signal Detection Theory metrics attributed this effect to a liberal shift in response bias rather than improved memory sensitivity. This suggests that the “boost” reflects an enhancement of category-level gist features rather than item-specific perceptual details. Trial-level analyses of pupillometry data at encoding revealed that pupil dilation predicted poorer item recognition, consistent with arousal’s suppression of peripheral information. However, this effect was attenuated in the presence of oddball tones, raising the possibility that the attentional boost acts through a disinhibitory mechanism that rescues de-prioritized information from suppression. Together, these findings provide a new perspective on ABE, revealing it may be a “fuzzy” memory effect that preferentially enhances the gist-level meaning of peripheral information.