Visual uncertainty in serial dependence : facing noise

Sammanfattning: Empirical evidence suggests that the visual system uses prior visual information to predict the future state of the world. This is believed to occur through an information integration mechanism known as serial dependence. Current perceptions are influenced by prior visual information in order to create perceptual continuity in an everchanging noisy environment. Serial dependence has been found to occur for both low-level stimuli features (e.g., numerosity, orientation) and high-level stimuli like faces. Recent evidence indicates that serial dependence for low-level stimuli is affected by current stimulus reliability. When current stimuli are low in reliability, the perceptual influence from previously viewed stimuli is stronger. However, it is not clear whether stimulus reliability also affects serial dependence for high-level stimuli like faces. Faces are highly complex stimuli which are processed differently from other objects. Additionally, face perception is suggested to be especially vulnerable to external visual noise. Here, I used regular and visually degraded face stimuli to investigate whether serial dependence for faces is affected by stimulus reliability. The results showed that previously viewed degraded faces did not have a very strong influence on perceptions of currently viewed regular faces. In contrast, when currently viewed faces were degraded, the perceptual influence from previously viewed regular faces was rather strong. Surprisingly, there was a quite strong perceptual influence from previously viewed faces on currently viewed faces when both faces were degraded. This could mean that the effect of stimulus reliability in serial dependence for faces is not due to encoding disabilities, but rather a perceptual choice.