Abstract
When perceiving visual stimuli, features are registered early, automatically, and in parallel, while objects are identified separately and at a later stage in processing (Treisman & Gelade, 1980). It has been suggested that people with dyslexia can develop enhanced peripheral vision to make use of a holistic strategy during visual search (Schneps, Brockmole, Sonnert, & Pomplun, 2012). This study explores whether dyslexic learners benefit from holistic strategies in a comparative visual search task. Participants included 18 individuals classified as dyslexic readers and 18 who were not. The experiment presented two blocks of 72 trials. Each trial consisted of two images to be compared side-by-side. Participants performed a conjunctive search to ascertain whether the two images were identical. In the first block, participants were provided no instruction regarding the visual strategy they were to employ. In the second block, participants were instructed to use a holistic viewing strategy – to "zone out" and perform the comparison by examining the whole screen at once. The results did not support the hypothesis of a dyslexic advantage when the holistic strategy was used. Using the holistic strategy, both groups scored 67.1% lower in accuracy (ηp2 = .671, F(1, 34) = 69.494, p < .001) and reacted 54.7% faster (ηp2 = .547, F(1, 34) = 41.052, p < .001), compared to accuracy and reaction time in the first block, controlling for the effect of learner group. Dyslexic learners spent 22% more time making the comparison decision in both conditions (ηp2 = .222, F(1, 34) = 9.678, p < .005) than their non-dyslexic counterparts, controlling for the effect of strategy employed. It is possible that the instruction to pursue a holistic strategy hindered both dyslexic and non-dyslexic participants' ability to focus visual attention on the conjunctive features of objects, integrate objects into working memory and perform comparative organization.
Meeting abstract presented at VSS 2016