Attentional control over masked visual processing

Abstract

We are constantly bombarded by a range of stimuli out of which only newlinesome cross the threshold of conscious awareness. It is now well-understood even newlinethose stimuli that we are not consciously aware of can nevertheless influence our newlinebehaviour. One of the enduring debates related to this topic is on the depths and limits newlineof such unconscious processing. While traditional theories of cognitive control have newlineassumed a tight link between consciousness and control, more recent theories have newlineproposed a role for executive control over unconscious cognition. The thesis aims to newlineaddress the question: to what extent is masked visual processing susceptible to newlinedifferent control mechanisms? Control settings can be manipulated in several ways. newlineThis thesis will focus only on attentional control. I take both a cross-sectional and an newlineindividual differences approach to examine this issue. Two different paradigms newlinetapping into different mechanisms will be used: the spatial orienting paradigm which newlinemeasures attention capture and the response priming paradigm which measures the newlineinfluence of masked primes on motor responses. I will show that associating reward newlinepoints with brief primes leads to enhanced priming effects. Deaf individuals are also newlineshown to display greater masked priming effects owing to their plasticity-induced newlineattentional advantage in visual processing. In another series of studies, I show that newlinebrief peripheral cues presented in task-irrelevant locations in a spatial orienting newlineparadigm can be ignored to some extent. Further, deaf individuals seem to be worse newlineat ignoring such irrelevant cues. Finally, I also address the issue of baseline in studies newlineon attention capture and conclude that the inappropriate use of baseline can lead to newlinex newlinemisleading results. Taken together, these studies suggest that masked visual newlineprocessing is not automatic in the traditional sense. I conclude that a more nuanced newlineapproach to the link between consciousness and control, in line with recent theories newlineon unconscious processing, is required. newlinexi