Connectionist Modeling of Experience-based Effects in Sentence ...

3.3 A Model of RC Processing
(a) “Phonological and articulatory representations must be activated in order to utter
the words for the load task”.
(b) “Phonological activation is an important component of written and spoken sentence
comprehension, particularly for certain difficult sentence structures”.
(c) “The extend to which phonological representations are important during comprehension
of difficult syntactic structures is likely to vary inversely with experience,
such that phonological information is more crucial for less experienced comprehenders”.
(d) “There appear to be notable individual differences in the ‘precision’ of phonological
representations computed during language comprehension, and these differences
are thought to owe both to reading experience and to biological factors.”
As becomes clear MC02 do not completely deny an influence of biological factors on
processing skill. These factors, however, concern the precision of representations, not
capacity limitations, and those are subject to experience-caused variance. Moreover are
individual differences assumed to be allocated primarily in the dependence on these
phonological representations, meaning that highly-skilled readers exhibit a more efficient
processing that does not rely so much on the phonological information. For example in
extrinsic load tasks 4 both the stored items and sentence comprehension processes make
use of shared phonological representations. Thus MC02 explain load effects by activation
interference rather than activation limits. This is seen as naturally evolving from
evidence that articulatory planning involves strict activation and inhibition of phonological
units (Bock, 1987; Dell and O’Seaghdha, 1992). Thus during extrinsic load tasks
activation and inhibition processes from both load and comprehension mechanism work
on the same representations, interfering with each other. The more effective processing
of highly experienced readers makes less use of the representation and, thus, reduces
difficulties due to interference. The same processes also happen in the reading span task
(which, by the way, is basically the same task as extrinsic load). The conclusion is that
reading span is a function of experience and not of memory capacity. This account is
also superior to Waters and Caplan (1996) because their theory assumes two separate
working memories and, hence, does not predict an interaction of comprehension and
extrinsic load. Furthermore also RC type differences are explained in the same way,
namely that “object relatives, which are more challenging than subject relatives, are
likely to rely more on phonological information than subject relatives” (p. 45).
4 In these tasks participants are asked to memorize a set of words or digits and retain it while reading
sentences. The extrinsic load influences the sentence comprehension performance in a certain way
that correlates with the participants reading span value (Just and Carpenter, 1992; King and Just,
1991).
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