A Study of Nonstrategic Linguistic Coding on Visual Recall of Learning Disabled Readers

Abstract

Three experiments directly investigated Vellutino's (1977) verbal-deficit hypothesis, which suggests reading difficulties of learning disabled children are attributable to deficiencies in linguistic coding. Short-term retention was studied using random shapes to minimize effects of prior verbal learning. Adopting a probe-type serial memory task, normal and LD readers were compared on recall performance after pretraining of named and unnamed stimulus conditions. Recall was markedly better for normal subjects trained with names compared with the unnamed control condition, while disabled children demonstrated inferior recall on named compared with unnamed pretraining. Experiment 1 demonstrated that verbal encoding effects were stronger for normal and deaf subjects than for disabled, especially on primacy positions. Experiment 2 suggested children s (normal and disabled) idiosyncratic verbal coding did not facilitate recall compared with names provided by the experimenter. Experiment 3 suggested that names for random shapes, regardless of age, facilitated recall for normal but not for disabled readers. Verbal codes appeared particularly important in differentiating groups at primacy positions. Consistent in all three experiments, no difference was found in recall of unnamed shapes between normal and LD readers. These experiments suggest that primary reading deficits are related to integrative linguistic deficiencies and not to deficiencies of visual memory or rehearsal.

Sound-Symbol Learning in Children with Dyslexia

“…In a summary of several of his own studies dealing with verbal and visual coding processes in children with and without reading disabilities, Swanson (1986) concluded that children of average intelligence who have dyslexia fail to use multiple codes in an additive fashion in memory tasks. Swanson's studies showed that label training increases memory for visual forms in skilled readers but seems to reduce recall in children with learning disabilities (Swanson, 1978(Swanson, , 1983(Swanson, , 1984. If children with dyslexia do not derive a memory benefit from using multiple codes, then perhaps the sound-symbol training aspect of phonics instruction only confuses them and interferes with their reading skill development.…”

“…There is some empirical evidence that part of the disability may be in visual perception and memory for the forms of letters or their position in a sequence (Badian, 1998;Cornoldi, Rigoni, Tressoldi, & Vio, 1999;Eden, Stein, Wood, & Wood, 1995;Morrison, Giordani, & Nagy, 1977; Slaghuis, Lovegrove, & Davidson, 1993). Visual limitations associated with dyslexia have also been attributed to perceptual (Badcock & Lovegrove, 1981;DiLollo, Hansen, & McIntyre, 1983;Eden et al, 1995;Enns, Bryson, & Roes, 1995;Gal-aburda & Livingstone, 1993; Slaghuis et al, 1993) and memory processes (Corkin, 1974;Enns et al, 1995;Morrison et al, 1977;Spring & Capps, 1974;Swanson, 1978Swanson, , 1983Swanson, , 1984.…”

“…Visual memory deficits in children with dyslexia have mainly been demonstrated in studies of visual memory span (Corkin, 1974;Morrison et al, 1977;Noelker & Schumsky, 1973;Senf & Freundl, 1971;Spring & Capps, 1974;Swanson, 1978Swanson, ,1983Swanson, ,1984. Some studies of visual memory have shown no impairment of immediate memory (Huba & Vellutino, 1990; Spring & Capps, 1974;Swanson, 1978Swanson, , 1984Swanson, , 1986.…”

Working Memory, Short-Term Memory, and Reading Disabilities

“…Although it has been argued that rehearsal or organization deficits are major problems of students with RD (see Swanson et al, 2004, for literature review), this notion is not held true across all studies. Several earlier studies have reported that differences in STM processes, such as rehearsal or chunking, do not distinguish between students with and without RD (R. L. Cohen, 1981;Swanson, 1983aSwanson, , 1983b. For example, some studies have found significant memory differences between students with and without RD when rehearsal is controlled and stimulus organization is provided (R. L. Cohen, 1981;Swanson, 1983b).…”