Friday, September 6, 2019

Visual Word and Pseudohomophone Effect Essay Example for Free

Visual Word and Pseudohomophone Effect Essay Over the past three decades, more cognitive psychologists have paid more attention to the processes involved in visual word recognition than to almost any other subject in their field. The annals of cognitive psychology have thus burgeoned with papers on word recognition while work on other topics, many relating to other aspects of reading such as syntactic parsing or discourse memory, have been substantially less popular. There are many reasons why work in one research area can take off and flourish; reasons which are sociological and pragmatic rather than just scientific. As far as visual word recognition is concerned, there are several sociological/pragmatic factors. One relates to the advent of new technology. The development of the microcomputer provided ready access to procedures for online control of reaction time (RT) and tachistoscopic experiments, and there are few simpler stimuli to present on-line than single printed words. With simplicity comes some degree of popularity. The advent of the microcomputer stimulated research into visual word recognition in a less trivial way too, because microcomputers allowed more sophisticated experimental procedures to develop than were hitherto possible. (Johnson, Rayner, 2007) In particular, by linking computer controlled displays to eye movement recording apparatus, experimenters began for the first time to gain direct evidence of the relations between eye movements and reading. A second reason for the popularity of visual word recognition is that simple tasks are at hand, for which accurate and sensitive measures can be derived, such as lexical decision, naming, and semantic classification. Further, and perhaps most importantly, these tasks can be related to models of word recognition, in which task performance is decomposed into a series of processing stages characterized by access to different knowledge representations. An example of this is the logogen model in its revised form. This model hypothesizes the existence of separate stored representations for orthographic, semantic and phonological representations of words. Different tasks may tap into different levels of representation. For example, lexical decisions may be accomplished by monitoring activation in the orthographic lexicon; word naming will require access to the phonological lexicon (at least for words with irregular spelling-sound correspondences); semantic classification requires access to stored semantic knowledge. By using such tasks, investigators could attempt to tap and test the characteristics of the different stages in the processing system. (Perea Carreiras, 2006) Thus, visual word recognition has proved attractive because it has a broadly specified multi-stage architecture, with the stages apparently open to testing via the judicious use of different tasks. Consequently it can serve as a test-bed for experiments concerned with such general issues as how stored knowledge influences perception. A third reason for the large body of research on word recognition is that it is a basic process in reading upon which all other reading processes are predicated. Moreover, other processes in reading, such as syntactic parsing, sentence comprehension and so on, may exert only relatively weak influences on the recognition of fixated words, at least in skilled readers. In essence, skilled word identification may operate as a relatively free-standing module, and so can be studied in isolation from factors affecting other reading processes. A fourth reason is that word identification is the interface between higher- order cognitive processes (such as those concerned with text comprehension) and eye movements. The effect of such higher-order cognitive processes on eye movements can be assessed by testing whether saccadic and fixation patterns on particular words vary according to the syntactic ambiguity of the sentence or according to whether the sentence contains a garden path. Studies of the relations between eye movements and word processing therefore speaks to the general issue of how the eye movement system is controlled. Most current accounts of visual word identification assume that, in normal subjects, letter processing takes place in parallel across the word. A much more controversial issue concerns the nature of the representation that mediates lexical access. (Holcombe Judson, 2007) This controversy has a long history in both experimental psychology and education. In recent years, the traditional view that reading is parasitic upon some form of speech code has given way to the view that orthographic codes (at least in skilled readers) dominate lexical access. Pseudohomophones are nonword letter strings like PHOX that, when pronounced according to the normal spelling-sound correspondences of English, yield a pronunciation identical to that of a word (in this case FOX), which will be referred to as the base word. Pseudohomophones were pronounced more rapidly than control nonwords matched for orthographic properties. This effect, they argued, indicated some contact with lexical representations. However, they also found that pseudohomophone latency was uncorrelated with the frequency of the base word in spite of the fact that, when the base words were named, a respectable frequency effect was obtained. Pseudohomophone effect has been used for another purpose: pseudohomophones take longer to reject than control nonwords in the lexical decision task. (Crutch Warrington, 2006) Again, the performance measured must (sometimes, to some degree) be reflecting contact with lexical representations. Yet, although they obtained such a pseudohomophone effect in their study, it was uninfluenced by the frequency of the base word. Hence, they argue, this lexical contact is not frequency sensitive. The alert reader will be impatient for the link to the reading of ordinary words. The account offered by McCann and Besner is as follows. For normal reading, an orthographic code is used to access a lexicon of orthographic word forms; the best-matching entry is then mapped to a lexicon of phonological word forms via a direct connection. Pseudohomophones activate entries in the phonological lexicon (inasmuch as they do) via a different spelling-sound conversion process (the assembly process of the three-pathway model). (Ferrand, Grainger, 2003) The absence of a frequency effect for pseudohomophones coupled with evidence that they do activate lexical representations (at least to some degree) indicates that mere activation of the phonological lexicon cannot be the locus of the frequency effect for ordinary naming. Therefore this must be localized in either (activation of) the orthographic lexicon (identification in my terminology) or the mapping process (retrieval). The locus of the effect is unlikely to be the former considerations of architectural parsimony suggest that the most plausible scenario is one where either both of these lexicons are frequency sensitive, or neither of them is. (Laxon, Masterson, Gallagher Pay, 2002) It is, therefore, conclude that a principal locus of frequency effects is within the links that join the various components of lexical memory. These links are commonly described as condition- action rules for mapping representations in one domain onto representations in another domain. For word naming, the relevant condition-action rules are those that link lexical entries in the orthographic input lexicon with lexical entries in the phonological output lexicon. It will be apparent that this argument is both indirect and heavily dependent upon a dubious appeal to parsimony. There may be more specific problems with their data. Inasmuch as they are examining effects of frequency upon access to a phonological lexicon used also for auditory recognition, and inasmuch as the assembly process may be assumed to operate on the letter string from left to right, it would be appropriate to control for the effects of a variable well known to have major effects on auditory lexical decision time, namely recognition point; that is, that point in the phonological string where it diverges from other words in the lexicon. The frequency of the base-word could only modulate this difference. Modulation of such a small effect cannot be easy to detect reliably. As a benchmark, it may be noted that the range of the frequency effect in both mixed and blocked conditions was only about half the difference between words and nonwords. (Bosman, 1996) Pseudohomophones are more orthographically word-like than their control nonwords in spite of their being roughly equated in terms of summed bigram frequencies. A stimulus such as brane is often referred to as a pseudohomophone in the word-recognition literature because it sounds like a real word despite the fact that it does not spell one. A common finding is that subjects in the lexical-decision task are slower to respond no to pseudohomophones like brane than to control items like frane. A related finding is seen in the naming task, except that the direction of the effect is reversed. Pseudohomophones like brane are named faster than control items like frane. (Ferrand Grainger, 1992) Pseudohomophones have also been used to explore differences between good poor young readers, differences between left and right hemisphere processing, sub-typing of young readers, mechanisms of spelling-to-sound-translation, dyslexic reading, types, of phonological codes and to identify the locus of word frequency effects in word recognition, identification and production. The standard explanation for these effects assumes that assembled phonology makes contact with lexical entries in the phonological lexicon. In the case of the lexical-decision task, this impairs performance because the output from the phonological lexicon signals the presence of a word (the phonological representation of brain) while the output from the orthographic lexicon signals that it is not a word, because there is no orthographic entry corresponding to brane. Resolving this conflict takes time. (Martin, 1982) In naming the process of assembling phonology for a visually presented nonword letter string that corresponds to a real word in the phonological domain is more efficient because of the interaction with a whole word representation in the phonological lexicon; nonwords that do not sound like a real word are denied this benefit. Because the presence of pseudohomophone effects in naming and lexical decision is embarrassing to a model which purports to give an account of these tasks, the tack they pursue is that pseudohomophone effects, when they are present in experiments, are not phonological in nature but simply reflect the fact that pseudohomophones are orthographically more similar to real words known to the reader than are the control items. (Rapcsak, Henry, Teague, Carnahan Beeson, 2007) Therefore, if pseudohomophones and control items are matched in terms of the orthographic and phonological error scores produced by the model, there will be no pseudohomophone effect in either naming or lexical decision. Indeed, this is the result they reported in one of their experiments. The application of pseudohomophones in lexical decision and priming paradigms for the study of adults with a history of developmental language disorders (DLD) has a distinct advantage over more explicit tests of phonological decoding such as nonword reading. With lexical decision measures it is possible to examine the early time course of phonological access and these techniques have been used effectively with a variety of patient populations that exhibit phonological processing deficits. The tasks tap implicit phonological awareness that may be present in the absence of explicit demonstrations that it exists. Based on previous research, it is predicted that the college-aged DLD readers in our study have phonological deficits that impact their word recognition ability and that this group will show less phonological awareness than their age-matched peers. (Simon, Petit, Bernard Rebai, 2007) Thus, our predictions for the current research are as follows. In the first experiment, a lexical decision task with pseudohomophones and orthographically controlled nonwords, it is predicted that control participants will show a typical pseudohomophone effect with slower and less accurate responses to pseudohomophones than to orthographic control nonwords. In contrast, it is predicted that the DLD group will not be as strongly influenced by the conflicting phonological information present in the pseudohomophone stimuli and will not show such an effect. In the second experiment investigating pseudohomophone semantic priming (e. g. , RANE-CLOUD) it is predicted that the non-DLD participants will produce reduced reaction times for target words when they are preceded by semantically related pseudohomophones. This predicted pattern of results would be consistent with the view that adults with a history of DLD continue to have phonological processing deficits. References Bosman AM; de Groot AM; Phonologic mediation is fundamental to reading: evidence from beginning readers.The Quarterly journal of experimental psychology A, Human experimental psychology; 1996 Aug; 49(3); p. 715-44 Crutch SJ; Warrington EK; Word form access dyslexia: understanding the basis of visual reading errors. Quarterly journal of experimental psychology (2006); 2007 Jan; 60(1); p. 57-78 Ferrand L; Grainger J; Homophone interference effects in visual word recognition. The Quarterly journal of experimental psychology A, Human experimental psychology; 2003 Apr; 56(3); p. 403-19 Ferrand L; Grainger J; Phonology and orthography in visual word recognition: evidence from masked non-word priming. The Quarterly journal of experimental psychology A, Human experimental psychology; 1992 Oct; 45(3); p. 353-72 Holcombe AO; Judson J; Visual binding of English and Chinese word parts is limited to low temporal frequencies. Perception; 2007; 36(1); p. 49-74 Johnson RL; Rayner K; Top-down and bottom-up effects in pure alexia: Evidence from eye movements. Neuropsychologia; 2007 Mar 7 Laxon V; Masterson J; Gallagher A; Pay J; Childrens reading of words, pseudohomophones, and other nonwords. The Quarterly journal of experimental psychology A, Human experimental psychology; 2002 Apr; 55(2); p. 543-65 Martin RC; The pseudohomophone effect: the role of visual similarity in non-word decisions. The Quarterly journal of experimental psychology A, Human experimental psychology; 1982 Aug; 34(Pt 3); p. 395-409

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