Word learning in dyslexic adults

I intend to examine whether dyslexic adults learn words similarly to typically developing adults. Though a preference for generalising shape to novel objects over other features of perceptual similarity, known as the shape bias, is usually strong by age 3 (Landau, Smith, & Jones 1988), Jones (2003) found 3-year-olds with vocabularies below the 30th percentile had no shape bias. I suspect dyslexic people acquire vocabulary slower early in life, and so may not acquire a shape bias during some critical period. My aim is to determine whether dyslexic people extend the same dimensions of novel objects as typically developing people. My procedure will follow the Dax Experiment paradigm used in Landau et al. (1988). A computer interface will display a novel object, whilst a voice says “This is a ___.” The screen will then display three novel objects matching the first in shape, size, or texture. The voice will then say “Show me a ___ (the same word as before).” The interface will record whether the participant chooses the object matching in shape. This will repeat several times. Ideally, I will have 15 typical and 15 dyslexic participants. I already have funding, and ethics approval is forthcoming. This research could suggest whether the shape bias must be acquired during a critical period. This could provide a deeper understanding of dyslexia, including how to fashion a more economical method of diagnosis, and the experimental methods could be replicated to test other learning difficulties or developmental disorders known to affect language development.