| dc.description.abstract | The aim of this thesis is to investigate the effect of parafoveal information on central
word processing. This topic impacts on two controversial areas of research: the
allocation of attention during reading, and letter processing during word recognition.
Researchers into the role of attention during reading are split into two camps, with some
believing that attention is allocated serially to consecutive words and others that it is
spread across multiple words in parallel. This debate has been informed by the results of
recent experiments that test a key prediction of the parallel processing theory that
parafoveal and foveal processing occur concurrently. However, there is a gap in the
literature for tightly-controlled experiments to further test this prediction. In contrast, the
study of the processing that letters undergo during word recognition has a long history,
with many researchers concluding that letter identity is processed only conjointly with
letter ‘slot’ position within a word, known as ‘slot-based’ coding. However, recent
innovative studies have demonstrated that more word priming is produced from prime
letter strings containing letter transpositions than from primes containing letter
substitutions, although this work has not been extended to parafoveal letter prime
presentations. This thesis will also discuss the neglected subject of how research into
these separate topics of text reading and isolated word recognition can be integrated via
parafoveal processing.
It presents six experiments designed to investigate how our responses to a central word
are affected by varying its relationship with simultaneously presented parafoveal
information. Experiment 1 introduced the Flanking Letters Lexical Decision task in
which a lexical decision was made to words flanked by bigrams either orthographically
related or unrelated to the response word; the results indicated that there is parafoveal
orthographic priming but did not support the ‘slot-based’ coding theory as letter order
was unimportant. Experiments 2-4 involved eye-tracking of participants who read
sentences containing a boundary change that allowed the presentation of an
orthographically related word in parafoveal vision. Experiment 2 demonstrated that an orthographically related word at position n+1 reduces first-pass fixations on word n,
indicating parallel processing of these words. Experiment 4 replicated this result, and
also showed that altering the letter identity of word n+1 reduced orthographic priming
whereas altering letter order did not, indicating that slot-based coding of letters does not
occur during reading. However, Experiment 3 found that an orthographically related
word presented at position n-1 did not prime word n, signifying the influence of reading
direction on parafoveal processing. Experiment 5 investigated whether the parallel
processing that words undergo during text reading conditions our representations of
isolated words; lexical decision times to words flanked by bigrams that formed plausible
or implausible contexts did not differ. Lastly, one possible cause of the reading disorder
dyslexia is under- or over- processing of parafoveal information. Experiment 6 therefore
replicated Experiment 1 including a sample of dyslexia sufferers but found no
interaction between reading ability and parafoveal processing. Overall, the results of this
thesis lead to the conclusion that there is extensive processing of parafoveal information
during both reading (indicating parallel processing) and word recognition (contraindicating
slot-based coding), and that underpinning both our reading and word
recognition processes is the flexibility of our information-gathering mechanisms. | en |
