How stability of the visual environment influences serial dependence

Abstract

This thesis investigated the phenomenon of serial dependence, the tendency for perception or judgments of a current stimulus to be influenced by previously encountered stimuli. The aim of the study was to explore the effect of various levels of uncertainty and environmental stability across extended sequences of stimuli on the strength of serial dependence. While existing research has shed light on the impact of uncertainty in the current stimulus on serial dependence, a comprehensive understanding of the role of uncertainty across multiple stimuli sequences remains elusive. To address this gap, we investigated the effects of uncertainty switches within different environmental contexts on serial dependence. A total of 24 participants took part in the experiment, each completing two sessions on seperate days. Participants observed sequences of Gabors (from 4-9) with varying spatial frequencies (1 or 0.33) and orientations, and were tasked with reproducing the orientation of the final Gabor using an adjustment task. Our results indicate that the level of uncertainty on the preceding trial significantly influences the bias on the current trial, with higher uncertainty leading to stronger serial dependence effects. Furthermore, transitions between uncertainty levels and the stability of the environment modulated serial dependence as well, with unpredictable environments eliciting greater reliance on previous information. This thesis emphasizes the nuanced relationship between uncertainty, environmental stability, and serial dependence, providing valuable insights into how the stability of the visual environment shapes the phenomenon of serial dependence and visual perception in general.