Perceptual Comparisons Modulate Memory Biases Induced by Overlapping Visual Input

Despite the active neural mechanisms that support the temporary maintenance of stimulus-specific information, visual working memory (VWM) content can be systematically biased towards novel perceptual input. These memory biases are commonly attributed to interference that arises when perceptual input is physically similar to current VWM content. However, recent work has suggested that deliberately comparing the similarity of VWM representations to novel perceptual input modulates the size of memory biases above and beyond stimulus-driven effects. Here, we sought to determine the modulatory nature of deliberate perceptual comparisons by comparing the size of memory biases following deliberate comparisons to those induced instead when novel perceptual input is ignored (Experiment 1) or encoded into VWM (Experiment 2). We find that individuals reported larger attraction biases in their VWM representation following deliberate perceptual comparisons than when they ignored or remembered the perceptual input. An analysis of participants’ perceptual comparisons revealed that memory biases were amplified when the perceptual input was endorsed as similar—but not dissimilar—to the current VWM representation. This pattern persisted even after the physical similarity between the VWM representation and perceptual input was matched across trials, confirming that perceptual comparisons themselves played a causal role in modulating memory biases. Together, these findings are consistent with the view that using a VWM representation to evaluate novel perceptual input risks exaggerating the featural overlap between them.