Applying El Greco Fallacy to Serial Dependence

Perceptual judgments are influenced by prior history, a phenomenon known as 'serial dependence.' It is believed that serial dependence reflects how the brain integrates perceptual priors, stemming from recent experience, with current sensory input, aligning with Bayesian and predictive coding principles. However, it is debated whether high-level perceptual priors influence lower-level perception (i.e., what is perceived) or if they impact only later processing stages (i.e., decision-making). To address this question, we employed the logic of the El Greco fallacy, which posits that systematic changes in perception should manifest in both the stimulus being perceived and the reporting tool. In each trial, participants reported whether sequentially presented pair of oriented Gabor patches (the target and test) had the same orientations. The test was either identically oriented to the target or rotated away by 8°. If serial dependence influences early vision, it should affect the perception of the target and test. Consequently, participants would more frequently judge the target and test as identical when they are identical, irrespective of the orientation shown in the preceding trial because the bias from the preceding trial would affect both stimuli similarly. Our preliminary findings suggest participants tended to choose the test rotated toward the preceding trial's target stimulus. In a second experiment, we controlled for the temporal distance between the target and the test, presenting the test at the same or different to the target location. Nevertheless, we found a consistent bias in perceptual judgments, aligning with the observations in Experiment 1. We propose that applying the El Greco Fallacy can potentially clarify the processing stages affected by serial dependence. Our preliminary findings suggest that the locus of serial dependence effects extends beyond early visual processing, offering important constraints on Bayesian and predictive processing perspectives of this phenomenon.