GENERAL CONCLUSIONS AND THEORETICAL IMPLICATIONS
7.2 THEORETICAL IMPLICATIONS
The experimental results, summarized above, indicate that there is an important change in reading performance which takes place once the developing reader is able to use a decoding strategy for processing new items. At the start of the experimental series, all the children could recognise the letters of the alphabet and could perform successfully in the rhyme and alliteration tasks. However, at 8 years of age the Poor Readers were unable to use this knowledge to support a decoding strategy when encountering unknown items. Their non-word reading was extremely poor and they did not show any regularity effect. When re-tested on the same stimuli twelve months later when age 9 years, they were beginning to be able to decode using letter-sound correspondences, but had not yet gained mastery over such a strategy. They were unable to use context consistently to enhance their reading of non-words. They were also, at this time, unable to differentiate between ordinary non-words and pseudo-homophones in Experiment 5 as well as showing no
pseudo-homophone ^ e c t in Experiment 4. This pattern of performance can be contrasted with that of the Good Readers who were able to read non-words, showed
Stainthorp/Chapter 7
a strong regularity effect and were able to differentiate between pseudo-homophones and ordinary non-words. The only experimental task that did not differentiate between the Good and Poor Readers was the lexical decision task. This task is one where a strong decoding letter-sound strategy would have been counterproductive and have produced a pseudo-homophone effect. A visual strategy would mean that the pseudo-homophones would be no more likely to be falsely detected as real words than the ordinary non-words. The lack of mastery of letter-sound decoding can account for the performance of the Poor Readers but, since the Good Readers were known to have good decoding skills it must be concluded that they had gained sufficient mastery to be able to use differential strategies depending on the task demands.
Thus, when the children were aged 8 and 9 years, the difference in performance between the two groups can be accounted for by the difference in ability to use a letter-sound decoding to approach unknown items. The Good Readers had superior letter-sound decoding skills and indeed these skills remained consistently higher for this group throughout the study. At the age of 8 and 9 years, the Good Readers had not perfected their skills, they still had to improve their processing to the point that it became automatised and in particular they needed to gain control over their decoding of vowels. However, the Good Readers were always in advance of the Poor Readers in the development of strategy and skill. When the children were 10 years old, the Poor Readers were able to use letter-sound decoding, but the Good Readers had begun to show greater accuracy in vowel reading which was an indication that they had begun to develop a more sophisticated decoding strategy based upon groups of letters. At that stage they had improved their non-word reading to near perfect level indicating that they had achieved mastery of simple letter-sound decoding.
The advanced decoding skills of the Good Readers led to them showing significant context effects when reading non-words when age 9 years which were even more
Stainthoip/Chapter 7
marked twelve months later. They were able to use the pseudo-sentence frame to prime an analogous real word and thereby this "orthographic" context would enable the non-word to be read using a combination of lexical knowledge and decoding skill. The limited decoding skills of the Poor Readers meant that they were unable to take advantage of the "orthographic" context initially at age 9 years, but they did show a context effect twelve months later. By then they were known to be able to use a decoding strategy, albeit at a lower level of skill than the Good Readers. Though both groups showed context effects when reading the non-words, their performance on the Adams and Huggins word reading test (Experiment 3) was evidence that the Poor Readers were still delayed in their reading strategies relative to the Good Readers. Both groups were able to make use of context to enhance the reading of the target irregular words, but the Poor Readers needed to do this at a higher level of word frequency than the Good Readers. The Good Readers had more advanced skills than the Poor Readers and as a consequence they had been able to develop a more extensive sight vocabulary of known words. There is corroboration for this interpretation of the data from the group differences in Experiment 6 - the Anomaly Detection and Correction task. The Good Readers were more likely to be able to supply the appropriate alternative to a real word anomaly; an indication of a more extensive sight vocabulary. The Good Readers were still in the position of having more extensive lexical knowledge to draw upon and more flexible strategies for processing words depending upon the task demands.
The major difference in performance between the two groups by the end of the study can be accounted for by the superior mastery of strategies for dealing with unknown items rather then a difference in type of strategy. There was some evidence that, by the end of the study, the Poor Readers were beginning to use
orthographic knowledge for processing words. More generally however, the
difference in word reading could be accounted for by the Good Readers having a larger number of items in their orthographic lexicons. The degree of automaticity
Stainthorp/Chapter 7
that this affords means that they had to pay less attention to the process of reading, leaving more capacity available for understanding. It is possible to speculate that possessing superior letter-sound decoding skills from an early stage allowed the Good Readers to read more extensively because it was easier for them. Thus they were able to build up an orthographic lexicon more quickly than the Poor Readers. Furthermore, this mastery of the letter-sound decoding and the possession of a substantial orthographic lexicon allowed them to take advantage of the regularities of orthography beyond the level of the letter. Thus they began to use orthographic units for parsing and analysing unknown items. Using larger units of analysis is more efficient with less room for error and it enables faster word recognition. This is likely to aid the further growth of the orthographic lexicon.
Thus, the Good Readers, whilst having superior decoding skills, would have a decreasing need to use them because they would have an increasing number of words with complete stored descriptions in the orthographic lexicon which could be accessed by a direct lexical route. The consequences for the Poor Readers of having less efficient decoding skills would be that they would have greater difficulty in elaborating their orthographic lexicons. However, because they had limited orthographic lexicons, they would not be able to access words directly and so would have to rely on those same limited decoding skills for a lot longer than the Good Readers.