Historically, educationally important individual differences
between learners were thought to be associated with specific
types of learning difficulties or impairments. Observations
of the loss of mental functioning in people who had acquired
brain injuries led to the development of theories about how
the brain works and, on this basis, educational interventions
were recommended to remediate or compensate for hypothesised
underlying impairments. Early work in special
education reflected the influence of these ideas on the development
of tests and interventions based on a model of
‘process training’, which assumed that underlying abilities
could be enhanced by training (Kavale, 2007). The Illinois
Test of Psycholinguistic Abilities, Frostig’s visual perceptual
training, diagnostic-prescriptive teaching and other tests
and interventions advertised or discussed in the pages of
Special Education: Future Trends promised much more than
they were able to deliver, as research on the educational
effectiveness of these interventions did not produce encouraging
results (for a review, see Kavale, 2007).