Fixation versus periphery in visual awareness: Differential effects of recent perceptual experience.

Abstract

Processing differences between foveal and peripheral vision mean that the location of objects in the visual field can strongly influence the way we experience them. The contents of visual awareness are believed to arise from interactions between sensory stimulation and context (e.g., expectations formed by recent experience), but the effect of visual field location on these interactions remains unclear. Here, we compared the effects of recent experience on awareness at fixation versus the periphery. On each trial, observers saw a brief display of an unambiguously rotating structure-from-motion prime sphere, followed by a brief display of a probe sphere with ambiguous motion. Experiment 1 established that conscious perception of the motion direction of the probe was more likely to differ from the prime when the stimuli were presented in the periphery compared with fixation. Experiment 2 ruled out a high-level, non-retinotopic, precision-weighting account of this effect by demonstrating that, although priming was apparent when the stimulus moved from fixation to periphery or vice versa, its magnitude was the same for low-precision peripheral and high-precision fixated primes. Experiment 3 replicated the original location effect and also found stronger motion adaptation in the periphery; the effects were not correlated, though, indicating that motion adaptation cannot account for the location effect. Experiment 4 replicated the location effect again and ruled out differences in fixation stability as the underlying mechanism. Overall, our results demonstrate a robust effect of visual field location on the integration of recent visual experience during construction of perceptual awareness and highlight the need to elucidate the mechanisms underlying differential generation of visual experience across the visual field.