Arquitectura Tecnológica actual de la DTIC [28]

The term ‘spoonerism’ derived its name from the Reverend William Archibald Spooner (1844-1930), Dean and Warden o f New College, Oxford who was reputed to commonly make errors in which the phonetic segments (usually the initial sounds) of two different words were switched - often with humorous consequences. While today many o f these attributions are now believed to be apocryphal they still clearly

demonstrate the nature of this speech error. Commonly quoted examples include such phrases as “You have hissed all my mystery lectures” when in fact Spooner meant to say “You have missed all my history lectures”; or famously, “Queer old dean” when referring to dear old Queen Victoria. These kind of unintended departures from planned utterances were given particular emphasis by Freud, who suggested that these and other kinds of speech errors were indicative o f repressed thoughts or desires. However modem psychologists have instead used such slips o f the tongue as the basis to investigate both the structure of lexical representations and speech production processes (Fromkin, 1973). The spoonerism in particular has been an especially popular type o f verbal slip for psycholinguistic research given the clarity o f its mutilation (MacKay, 1970).

While spoonerisms may occur naturally in spontaneous speech, techniques were developed to increase the frequency of which spoonerism errors were elicited in the laboratory. Word pairs that were to be read aloud were preceded by ‘interference’ word pairs. These were designed to resemble the phonology o f the desired spoonerism pair more closely than the phonology of the subject’s intended target. For example when the target word pair ‘fruit fly’ was preceded by the interference words ‘flag - fraud’ participants were more likely to generate the spoonerism ‘flute - fry’. This technique has been useful in establishing the factors that influence the probability of spoonerism frequencies. Motley and Baars (1975) for example, using this technique demonstrated that the frequency of spoonerism production is affected by the

phonotactic probability of the initial word stmcture and the lexical legitimacy of the error.

In contrast to such unintended spoonerism production, it was some time before experimental tasks were designed which explicitly required participants to switch

word sounds in a systematic fashion. While this task requires skill in verbal short-term memory, blending and non-word articulation it is primarily taken to reflect proficiency in phonological segmentation. Perin’s (1983) seminal study was the first to employ a simple spoonerism task in which subjects were asked to switch the initial sounds o f word pairs (in this case pop groups or names o f famous singers). The aim o f the study was to evaluate the relationship between phonemic segmentation ability and literacy skill in groups of good and poor readers. Perin reported that performance on this task was strongly related to spelling rather than to reading skill, and concluded that poor spellers - irrespective o f their reading skill - had difficulty operating on the phonemic level o f speech. The use o f such spoonerism tasks in addition to other tasks requiring manipulation of phonetic segments of words (e.g. tasks o f pig latin, phoneme insertion or deletion) are now commonly used as an index o f phonological awareness in both clinical and research contexts. Studies investigating the phonological processing skills of dyslexic adults have demonstrated that deficits on tasks o f word sound

manipulation persist into adulthood (Felton, Naylor and Wood, 1990; Pennington, Van Orden, Smith, Green, and Haith, 1990). Tasks which specifically require word

spoonerising have also been explicitly presented to adult dyslexies; accuracy of response is generally taken as the dependent variable (Hanley, 1997) but a few studies have measured both accuracy and speed o f response (Paulesu, et al., 1996; Snowling, Nation, Moxham, Gallagher and Frith 1997; Brunswick et al., 1999). Dyslexic

participants, even those who have reached a university level o f education, make more errors and respond more slowly on these tasks. This has been taken to represent evidence o f a persistent and continuing deficit in phonological processing in developmental dyslexia that is not mitigated by improvements in overall literacy ability (Brunswick et al., 1999).

2.12. Conclusions

Although the most apparent indications o f dyslexia relate to reading and writing, it is evident that the difficulties o f dyslexic individuals extend beyond literacy and include a variety o f tasks which require phonological processing. Evidence for impairments in phonological repetition, picture naming and spoonerising have been reviewed. These impairments are unlikely to be attributable to difficulties in vocabulary, since even when vocabulary level is controlled relative impairments on these tasks persist.

Instead researchers have attributed repetition and naming difficulty to one of

phonological retrieval. Specifically it has been suggested that phonological

representations are degraded or poorly specified in the dyslexic, leading to difficulty in any task where these representations are accessed or manipulated.

Phonological R e p r esen ta tio n Verbal STM _{Nam ing} R eading R ep etition Paired A s so c ia te Learning P honological a w a r e n e s s

Figure 2.10. C a u s a l lin k s a m o n g th e d iffe re n t p h o n o lo g ic a l p ro c e s s e s a n d re a d in g (fro m S n o w lin g , 2 0 0 0 , p .5 9 ).

In this way the phonological impairment is postulated to represent a core deficit, accounting for poor performance on a variety of apparently disparate tasks. This is illustrated in Figure 2.10. (from Snowling, 2000; p.59). One hypothesis is that the phonological representations themselves are poorly or inadequately specified. It has been suggested that such a lack of specification, in terms of phonological encoding, while congruent with many of the experimental findings in the literature, is

nonetheless lacking in explanatory power. For example, poor phonological

representation does not account for the clear context sensitivity in tasks of naming - and in particular why naming items in a continuous rapid format particularly taxes dyslexic individuals. This has led to the proposal that dyslexia may be characterised by an additional deficit in speed of processing (e.g. Wolf, 1991) which extends beyond the linguistic domain. Nor does the representation hypothesis adequately explain why reading is strikingly more impaired than naming given that the same phonological representation is retrieved in each case.

In contrast, the competition hypothesis attributes poor phonological processing to the inefficient resolution of competition effects at the phonological level. The advantage o f this perspective is that it predicts normal task performance on tasks where such competition is low. While this is possible for picture naming, reading an inconsistent orthography such as English will always entail a high degree o f phonological

competition. The experiments in this thesis have been designed to further investigate the cognitive basis o f the phonological deficit in dyslexia by manipulating those factors that are hypothesised to influence phonological competition: modality (words vs. pictures), rate of naming, and word length.