Lecturer's Précis - Ellis and Young (1988)
"Human
Cognitive Neuropsychology"
Copyright Notice: This material was
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First published online 10:54 BST 3rd May 2002,
Copyright Derek J. Smith (Chartered Engineer). This version [2.0 - copyright] 09:00 BST 3rd July
2018.
An earlier version
of this material appeared in Smith (1997; Chapter 5). It is repeated here with
minor amendments and supported with hyperlinks.
The Ellis and
Young (1988) Transcoding Model
See firstly the supporting commentary for this material.
This is the first of the large scale psycholinguistic models to be widely published. It is derived from the earlier models via Ellis (1982), and is a good example of how to display highly modular cognitive processing in dataflow diagram (DFD) form. It shows the flow of information during both spoken and written language, makes some important theoretical judgements as to the cognitive modularity involved, and uses flowlines to interconnect the various resources.
The Ellis and
Young (1988) Model: Numbers refer
to the notes which accompanied the original. Input streams are shown at the
top, and output streams at the bottom. Spoken language is shown to the left, and written language to the right. This gives four
distinct processing routes, namely speech perception (top left), reading (top
right), speech production (bottom left), and writing (bottom right). The central, or "semantic" system, is common to all
four processing routes, but has been deliberately left
"underspecified" to avoid swamping the surrounding detail. This is
where the input routes terminate (with the creation of some sort of understanding
of the material presented), and it is where the messages for production by
the output routes actually originate (with the emergence of some sort of
communicative intention). Following the lead set by Freud (1891), the
semantic system is shown surrounded by four lexicons, one for each of
the processing routes. These are where whole known word forms are
stored. The two output routes are clear examples of motor hierarchies. Bypass
Routes: Some important routes allow
information to flow around rather than through the central
array of lexical-semantic modules. The main bypass routes are: Route 11: This route allows the semantic system and the two auditory lexicons
to be bypassed. This gives us the ability to copy unrecognised and
essentially meaningless sounds, as for example when presented with material
in an unknown language (compare Route 23 below). Route 15: This
route allows the graphemes making up unfamiliar words to be "sounded
out", and converted into their equivalent sound patterns. This then
allows nonsense words, unfamiliar words, and foreign words to be spoken out
loud either (a) mentally, by "talking to yourself" along Route 11
and then recognising what you are saying along Route 2, or (b) actually, by
continuing downwards along the (unnumbered) speech production route. Route
18: This route allows sounds to be assigned letter equivalents. This
then allows nonsense words to be written to dictation. If Routes 11 and 18
are combined, it allows the phonetic transcription of sounds other than those
making up known words. Route 23: As for Route 11 above, but
bypassing the two visual lexicons, and giving us the
ability to copy unrecognised text, as when dealing with an unknown language. Feedback
Routes: Other important routes
allow information to be fed back from a later process to an earlier one.
These are of two sorts - single-ended arrows pointing up the page, and
double-ended arrows. The main feedback routes are: Route 10 (upper arrow): This route allows feedback from the speech
production process to the word selection process. This allows speech output
to be properly paced. New words or phrases are not released for articulation
until the word or phrase currently being articulated is nearly and
successfully finished with. Should articulation problems be encountered (a
dry throat, say, or a mispronunciation), the whole process is immediately
interrupted. Route 11 (upper arrow): This route allows internal
feedback from the speech production process to the auditory analysis process.
The authors suggest that this might provide "a mechanism for what we
experience in everyday life as 'inner speech', where we appear to hear our
own silent speech internally" (p226). Route 12: This route
allows external feedback from the final act of speech production to the
auditory analysis process. This is where we hear our own voice coming back to
us through our ears. Route 22: As for Route 12, but for
writing-reading rather than speaking-hearing. This is where we see our own
writing coming back to us through our eyes. Clinical
Evidence: The model reflects a
large body of clinical evidence, from Wernicke (1874) to Marshall and Newcombe
(1973). Any one named process or
information flow can be damaged more or less in isolation, and language
behaviour will suffer in a very particular way as a result. Generally
speaking, damage to the semantic "hub" of the model will result in
what is known as a "deep" defect such as an agnosia, whilst damage
to "outer ring" processes will result in a variety of dysphasias, anomias, dyspraxias and dysarthrias.
Here are some specific defects:
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Redrawn from Ellis and Young (1988:222). This version Copyright © 2002, Derek J. Smith. |
References
Coltheart, M
(1980). The semantic error: Types and theories. In Coltheart,
M., Patterson, K., & Marshall, J.C. (Eds.), Deep Dyslexia.
London: Routledge & Kegan Paul.
Ellis, A.W.
(1982). Spelling and Writing (and Reading and Speaking).
In Ellis, A.W. (Ed.), Normality and Pathology in Cognitive
Functions. London: Academic Press.
Ellis,
A.W. & Young, A.W. (1988). Human Cognitive Neuropsychology. Hove, UK: Erlbaum.
Michel,
F. & Andreewsky, E. (1983). Deep dysphasia: An analogue of deep dyslexia in the
auditory modality. Brain and Language, 18:212-223.
Smith, D.J.
(1997). Human Information Processing. Cardiff:
UWIC. [ISBN: 1900666081]