Does Parallel Distributed Processing Provide a Plausible Framework for Modeling Early Reading Acquisition

A study compared a parallel distributed processing (PDP) model with a more traditional symbolic information processing model that accounts for early reading acquisition by human subjects. Two experimental paradigms were simulated. In one paradigm (a "savings" paradigm) subjects were divided into two groups and trained with two sets of stimuli: consistent orthographic representation of voicing, or inconsistent mapping of orthography onto voicing. A total of 32 simulated trials were generated with each model. Analysis of the savings paradigm data for the symbolic model revealed no significant main or interaction effects. Analysis of the PDP data revealed significant main and interaction effects. A second paradigm involved a forced-choice task testing subjects' ability to make use of analytic generalization. A total of eight simulated trials were generated with each model. Analysis indicated no significant difference between the symbolic model and chance performance, while the PDP model had perfect performance, indicating that the network had learned to make use of the orthography-voicing relationship implicit in the stimuli. Findings suggest that, in the domain of early reading acquisition, the problem with the PDP model approach is not that it is too weak but that it is too strong--even the simplest PDP models exhibit learning beyond what is observed in human subjects faced with similar learning tasks. (Contains 18 references. An appendix of data is attached.) (RS) *********************************************************************** * Reproductions supplied by EDRS are the best that can be made * * from the original document. * *********************************************************************** A Paper Presented at the Annual Meeting of the American Educational Research Association April 4, 1994 Session 1.34, Reading in Children OEPAPCIVENT Of EOUCAT '3N Othce ot Educahonal R11BarCh 1111d Imorovement EDUCATIONAL RESOURCES INFORMATION CENTER (ERIC) )1% TN, document has been reproduced alt recerved from the person or 0(0.1121010ft 0,1(1111aIMQ 0 'Amor changes have 04On made to winger, reoroduCtion Quality Points of mew on opniOns slated 411 this clOCtr meat dO not necessarily rsPrellent official OERI oos.hon or pohcy Does parallel distributed processing provide a plausible framework for modeling early reading acquisition? John E. McEneaney Indiana University South Bend JMcEnean@Indiana.edu "PERMISSION TO REPRODUCE THIS MATERIAL HAS SEEN GRANTED BY TO THE EDUCATIONAL RESOURCES INFORMATION CENTER (ERIC):' Parallel Distributed Processing (PDP) models are central to a great deal of current research in the cognition of reading and are beginning to assert an influence well beyond the boundaries of the cognitive science research community. Adams (1990), for example, has grounded an argument for a specific approach to beginning reading instruction on a PDP model of word learning (Seidenberg & McClelland, 1989). Ehri (1992) has begun to adopt PDP concepts in explaining the development of sight word reading, and researchers with interests in learning difficulties (Seidenberg, 1992; Patterson, Seidenberg, & McClelland, 1989) have begun to model disabilities through simulated "lesioning" of working PDP systems. There is evidence, however, that the currently dominant PDP models of reading (McClelland & Rumelhart, 1981, 1988 pp. 203-239; Seidenberg & McClelland, 1989) are missing essential aspects of the cognition of early word perception and learning. One consistent general problem has been that the distributed representation of knowledge in PDP models is difficult to reconcile with the acquisition and use of distinct perceptual units (e.g. onsets and rimes) that appear to play an important role in learning to read (Treiman, 1992; Goswami, 1986, 1988). Another problem concerns the data sets used in testing the adequacy of PDP models which have relied almost exclusively on mature adult readers even in models that make explicitly developmental claims (e.g. The Seidenberg & McClelland (1989) developmental model cites 29 empirical studies only 1 of which employed children as subjects. ) But neither of these limitations are theoretically critical in the sense that they rule out the PDP approach as an appropriate framework for models of early literacy acquisition. Recent research in reading acquisition suggests, however, that a critical test of the adequacy of PDP models in explaining early reading acquisition may be at hand. As a consequence of a series of carefully controlled studies Byrne (1992) has identified what he calls the "default acquisition procedure" for reading. Briefly, these studies (Byrne, 1984, 1992; Byrne & Carroll, 1989) investigated the way chilthen learn to read new orthographies and found that, in the absence of explicit training in orthographic analysis, children adopt a non-analytic (i.e. paired associate) approach. Despite being provided with a completely regular sound-symbol system, the children did not induce phoneme-grapheme correspondences over extended periods of training. Moreover, in a series of related studies exploring the learning of new orthographies by adult subjects the same default procedure was evident at a sub-phonemic level. Although adult subjects recognized the alphabetic character of the orthography at the syllable and word levels, they did pot discover the underlying system of regularity between the orthography and sub-phonemic feature elements including the voicing contrast which has been shown to have high percept l salience (Miller & Nicely. 1955).