Abstract:

Visual information is essential to deaf people given their early auditory deprivation. Some researchers have proposed a perspective in which the distribution of deaf visual attention resource shifted from the central to the extrafoveal visual field. This study explores how this unique visual processing ability may influence reading in deaf people and proposes ‘the effect of parafoveal visual attention enhancement in deaf reading.’ We hypothesise that visual attention resources are reorganised due to the absence of auditory input for deaf people. This reorganisation increased distribution toward the extrafoveal field, but decreased it in the foveal field, resulting in poor reading efficiency.

A total of 29 severely to profoundly deaf students (DS) from a deaf school in Tianjin participated in the present study. Their hearing loss is ≥ 90 dB in the better ear. Participants are either born deaf or became deaf before three years old, and they use Chinese Sign Language (CSL) as their main communication mode. None of them received a cochlear implant. The age control group (AC) has 29 hearing middle school students, which indicated no significant difference in chronological age with DS. In addition, 29 hearing primary students comprised the reading-level control group (RC). The DS and RC were examined through a series of reading tests, including orthographic judgment task, reading fluency and reading comprehension, to match their reading levels. All participants read Chinese sentences for comprehension as their eye movements were tracked. A total of 48 pairs of target words (48 high frequency and 48 low frequency words) were embedded in two different sentence frames. All sentences consisted of seven or eight double-character words. These sentences were either presented normally or in a disappearing text paradigm that, as each word (n) was fixated, the word (n) or the next word (n + 1) remained visible only for a short period (40 ms) before disappearing. The paradigm was utilised to manipulate the display duration for the parafoveal word n + 1 (Experiment 1) or the foveal word N (Experiment 2) respectively, to compare the efficiency (speed) of encoding visual text information in sentence reading.

In Experiment 1, when word n + 1 was presented briefly (40 ms), the overall sentence reading times were prolonged only for reading-level control group, but no difference was observed between deaf students and age control group. The effect of word frequency on target words was normal for all three groups. By contrast, in Experiment 2, during which word n was presented briefly (40 ms), the overall sentence reading times were prolonged only for deaf students. For gaze duration, the effect of word frequency for target words disappeared for deaf students. Therefore, deaf students showed higher efficiency of encoding parafoveal text information than their reading-level controls in Experiment 1 and were equal to their age controls. However, in Experiment 2, deaf students showed lower efficiency in encoding foveal text information than those in the hearing controls.

In conclusion, the present study confirmed that deaf readers have enhanced parafoveal processing of linguistic information, but their foveal processing was hampered as a consequence. Thus, parafoveal visual attention was enhanced in deaf reading, which may be one of reasons for reading difficulty. Further research is necessary to explore this issue.

Key words: deaf, effect of parafoveal visual attention enhancement in deaf reading, disappearing text, eye movements, Chinese reading