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Word length effects in the left and right cerebral hemispheres : the right visual field advantage

It has long been known that word length has a larger influence on the recognition of words presented in the left visual field than the right visual field, an effect commonly referred to as the length by visual field interaction. The aim of the present thesis was to explore the neural and behavioural effects of the length by visual field interaction. In doing so, it was expected that the results would contribute to and extend the body of behavioural research in this area, particularly in regard to the hemispheric processing of words. Chapter One presents a general overview of the thesis; in Chapter Two, the nature of the right visual field advantage is reviewed, with particular reference to previous work that has demonstrated differential effects of word length in each of the cerebral hemispheres. Models that seek to account for visual field asymmetries are also reviewed. Chapter Three outlines the key methods adopted in the thesis, namely, the divided visual field task and the use of event-related potentials. Chapters Four and Five present the results of two experiments that explored the neural effect of increasing word length in each of the hemispheres. The results provided ERP evidence of early processing dissociations between the hemispheres in terms of words and non-words of different lengths. Experiments 3-6 explored the effect of orthographic uniqueness point in each of the visual fields, as a means of exploring the nature of processing conducted by each hemisphere. Across three experiments, it was shown that words with a late uniqueness point were recognised faster and more accurately than words with an early uniqueness point. This facilitation for late uniqueness point words was evident in the ERP response at 170ms. Furthermore, orthographic uniqueness point was shown to differentially affect each of the hemispheres. Experiments 6-9 provided evidence to suggest that the interaction of length and visual field was influenced by orthographic depth, a property of language that reflects the transparency with which sounds are represented in print. In Chapter Ten, the effect of format distortion on the interaction of length and visual field was explored. Finally, Chapter Ten summarises and discuss the key findings of the present thesis in light of theories that seek to account for lateralised word recognition.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:678555
Date January 2011
CreatorsWright, Victoria Caroline
ContributorsIzura, C.
PublisherSwansea University
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttps://cronfa.swan.ac.uk/Record/cronfa43173

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