The time course of visual processing: Backward masking and natural scene categorisation

• Published in: Vision research (Oxford) 2005-05, Vol.45 (11), p.1459-1469
• Main Authors: Bacon-Macé, Nadège, Macé, Marc J.-M., Fabre-Thorpe, Michèle, Thorpe, Simon J.
• Format: Article
• Language: English
• Subjects: Adult; Backward masking; Behavioral psychophysiology; Biological and medical sciences; Case-Control Studies; Chi-Square Distribution; Discrimination (Psychology); Early processing; Electroencephalography; Electrophysiology; Event-related potentials (ERP); Female; Fundamental and applied biological sciences. Psychology; Humans; Information integration; Life Sciences; Male; Middle Aged; Natural images; Neurons and Cognition; Perception; Perceptual Masking; Perceptual Masking - physiology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Psychophysics; Reaction Time; Sensitivity and Specificity; Statistics, Nonparametric; Vision; Visual Pathways; Visual Perception; Visual Perception - physiology
• ISSN: 0042-6989; 1878-5646; 0042-6989
• DOI: 10.1016/j.visres.2005.01.004

Human observers are very good at deciding whether briefly flashed novel images contain an animal and previous work has shown that the underlying visual processing can be performed in under 150 ms. Here we used a masking paradigm to determine how information accumulates over time during such high-level categorisation tasks. As the delay between test image and mask is increased, both behavioural accuracy and differential ERP amplitude rapidly increase to reach asymptotic levels around 40–60 ms. Such results imply that processing at each stage in the visual system is remarkably rapid, with information accumulating almost continuously following the onset of activation.