The research reported in this thesis provides a functional analysis
of reading and short term memory in dyslexic children.
Research into dyslexia is reviewed and the approach of Cognitive
Psychology is explained. Twenty four experiments are then reported.
These compare dyslexic and control children's abilities on a number
of tasks which tap functions thought to be involved in language processing
and reading. These functions are iconic coding, visual encoding,
lexical encoding, and articulatory encoding. It is concluded
that older developmental dyslexics behave as a uniform group with
their common disability at lexical encoding. Further experiments
investigate the internal mechanisms conceptualized to be involved in
lexical encoding: the visual input lexicon, the auditory input lexicon
and the output lexicon. While the primary disability in dyslexia
is thought to be in the operation of the visual input lexicon, some
residual deficiency is found in the operation of all lexical encoding
mechanisms. These findings are related to a multifactorial view of
the causation of dyslexia and to considerations of other dyslexic
symptoms.
The experimental evidence of good and poor readers' differing
short-term memory spans is reviewed, and when this is considered in
conjunction with the functional analyses reported here, there arise
implications for a conceptualization of STM. Some of these implications
are tested empirically, and a functional model of reading and
STM is developed.