The Role of Perceptual Load in Orientation Perception, Visual Masking and Contextual Integration

摘要: Previous research of the effects perceptual load on visual processing demonstrates reduced sensitivity and neural activity for task-irrelevant stimuli under high compared to low load. However, precise underlying mechanisms remain unclear. The present thesis approaches this question by assessing interactions between level their context different levels results from Chapter 2 demonstrate that modulates perception orientation not only reducing overall signal gain but also broadening tuning profile. These findings suggest reduces strength extent which is discriminated noise; thus altering contextual interaction. 3 further role in establishing tilt-illusion, thought rely purely among orientations. show increases impact (leading greater tilt-illusion) subthreshold presentation, precludes top-down suppression context. Chapters 4 5 establish efficiency separating noise with higher load, found when are presented successively (as backward masking). time course shows a distinct pattern both, more effective longer lasting masking This evolves rapidly indicates low-level integration an early locus It persists at later periods metacontrast object substitution where stimulus mask do spatially overlap, indicating stages. Together, provide mechanistic explanations