Journal of Vision - Unconscious orientation processing depends on perceptual load, by Bahrami, Carmel, Walsh, Rees, & Lavie

Bahador Bahrami	Institute of Cognitive Neuroscience, University College London, London, UK, & Department of Psychology, University College London, London, UK
David Carmel	Institute of Cognitive Neuroscience, University College London, London, UK, Department of Psychology, University College London, London, UK, & Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, London, UK
Vincent Walsh	Institute of Cognitive Neuroscience, University College London, London, UK, & Department of Psychology, University College London, London, UK
Geraint Rees	Institute of Cognitive Neuroscience, University College London, London, UK, & Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, London, UK
Nilli Lavie	Institute of Cognitive Neuroscience, University College London, London, UK, & Department of Psychology, University College London, London, UK

The effects of perceptual load on the level of adaptation to task-irrelevant and invisible oriented gratings were examined. Participants performed a task at fixation under conditions of low (detecting color targets) or high (detecting conjunctions of color and shape) perceptual load. Simultaneously, a task-irrelevant-oriented grating was presented monocularly in a more peripheral location but was suppressed from awareness by flashing a dynamic mask stimulus at the same retinal location in the other eye. Orientation-specific adaptation to the invisible irrelevant grating was found at low perceptual load but was eliminated with high perceptual load. These results demonstrate that early unconscious processing of orientation depends on the allocation of limited attentional capacity, and conversely that the allocation of attentional capacity under low (versus high) load is insufficient to bring orientation representations to awareness.