Scott Janetsky¹, Kuo-Wei Chen¹, Kenzy Moustafa¹, Gi-Yeul Bae¹; ¹Arizona State University

Visually-guided behaviors can be systematically influenced by recent perceptual history. For example, reports in a location working memory task exhibit repulsive biases away from task-irrelevant prior stimuli. The prevailing theories suggest that repulsive serial bias is best explained by low-level adaptation that directly alters the perceptual representation during the stimulus encoding. However, empirical evidence for this low-level adaptation account is limited. Here, we sought to find empirical evidence for the low-level adaptation account via a correlation approach. In the experiment, 40 participants performed both a location estimation task with an inducer designed to measure adaptation-induced repulsive bias (i.e., visual aftereffect) and a typical location delayed estimation task designed to measure repulsive serial bias. In the analysis, we correlated the adaptation-induced repulsive bias with the repulsive serial bias. We hypothesized that if the repulsive serial bias is driven by low-level adaptation, then it should be positively correlated with adaptation-induced repulsive bias. We confirmed that both tasks exhibited repulsive biases. However, the two biases were not correlated (BF for the null = 2.8). In subsequent analyses, we investigated whether the biases were associated with post-perceptual decision processes by examining response time as a function of the stimulus difference between the current and the prior stimuli, and the difference between the target and the inducer. We found that response time was slower when the current stimulus was more similar to the prior stimulus in repulsive serial bias, indicating the decision was more difficult in such trials. However, this was not the case in adaptation-induced repulsive bias, indicating that the inducer directly altered the perception of the target stimulus. Together, these results suggest that repulsive serial bias is driven by decision-related processes that integrate the prior stimulus rather than by low-level adaptation that directly impacts the representation of the stimulus itself.