Visual word recognition in deaf readers: lexicality is modulated by communication mode

Abstract

Evidence indicates that adequate phonological abilities are necessary to develop proficient reading skills and that later in life phonology also has a role in the covert visual word recognition of expert readers. Impairments of acoustic perception, such as deafness, can lead to atypical phonological representations of written words and letters, which in turn can affect reading proficiency. Here, we report an experiment in which young adults with different levels of acoustic perception (i.e., hearing and deaf individuals) and different modes of communication (i.e., hearing individuals using spoken language, deaf individuals with a preference for sign language, and deaf individuals using the oral modality with less or no competence in sign language) performed a visual lexical decision task, which consisted of categorizing real words and consonant strings. The lexicality effect was restricted to deaf signers who responded faster to real words than consonant strings, showing over-reliance on whole word lexical processing of stimuli. No effect of stimulus type was found in deaf individuals using the oral modality or in hearing individuals. Thus, mode of communication modulates the lexicality effect. This suggests that learning a sign language during development shapes visuo-motor representations of words, which are tuned to the actions used to express them (phono-articulatory movements vs. hand movements) and to associated perceptions. As these visuo-motor representations are elicited during on-line linguistic processing and can overlap with the perceptual-motor processes required to execute the task, they can potentially produce interference or facilitation effects.

Figure 1. Visual Lexical Decision Reaction times.

SEM in brackets.

Figure 2. Lexicality effect and phonological fluency task.

Scatterplot depicting the mean number of correct responses for each participant within groups (FAS z score), plotted against reaction time difference score between words and consonant strings (Lexicality score).

Figure 3. Lexicality effect and semantic fluency task.

Scatterplot depicting the mean number of correct responses for each participant within groups (CAT z score), plotted against reaction time difference score between words and consonant strings (Lexicality score).