The processing of multiple letters and multiple words in deaf adults

Readers utilize both foveal and parafoveal information to recognize letters and words effectively. In the fovea, the ability to identify letters is maximized, resulting in greater accuracy for letters that are directly fixated upon. Conversely, the accuracy of letter identification diminishes in the parafovea. Notably, letters at the beginning and end of words are often recognized more accurately than those in the middle, which yields a W-shaped function in identification accuracy and an M-shaped function in response times. Building upon these observations, word identification rates are higher for strings presented in the foveal area. Due to an attentional bias toward reading direction, there exists a greater ability to identify words in the right parafovea compared to the left. Given that deaf readers display a distinct distribution of visual attention, the present study aims to investigate, using a Rapid Parallel Visual Presentation paradigm, whether deaf readers differ in their ability to identify letters and words. Participants were presented with three-letter nonword and word sequences at foveal and parafoveal positions and instructed to identify post-cued letter and word targets. While both groups demonstrated the W-shaped accuracy function for letter identification, response times for deaf readers were characterized by a distinct M-shaped pattern, particularly for letters in the right visual field (RVF). Hearing participants exhibited a RVF advantage in word identification; however, deaf participants displayed a reduced RVF advantage, suggesting a more bilateral distribution of visual attention during reading. These results indicate that deafness leads to subtle yet significant differences in letter and word identification processes.