The impact of clarity on hearing-impaired children's face processing: An eye-tracking study

Faces contain a wealth of information, and facial processing plays a significant role in individuals' social development. Facial processing typically includes two methods: holistic processing and local processing. Normal hearing individuals primarily engage in holistic processing when dealing with faces of varying clarity, while hearing-impaired individuals show a local processing advantage for clear faces compared to normal hearing individuals. However, for hearing-impaired individuals, it is still inconclusive which processing method is dominant, and it is unclear whether there is a local processing advantage under low clarity, blurred conditions. Therefore, this study selected 30 hearing-impaired children aged 8-14 years as participants and used normal hearing children as the control group. By employing eye-tracking technology and manipulating the clarity of face images, the study explored the impact of different levels of clarity on the holistic and local processing of faces by hearing-impaired children. The results showed that as facial clarity decreased, the overall judgment accuracy (ACC) of both groups declined, and their reaction times (RT), first fixation duration (FFD), and fixation duration (FD) on the whole face increased. Both groups spent significantly more FD and fixation counts (FC) on the eyes and mouths of clear faces than on blurred faces. Hearing-impaired children's overall judgment ACC and FD for both holistic and local processing were inferior to those of normal hearing children. These results indicated that clarity affected the processing methods of both groups' faces, with a greater reliance on holistic processing and less on local processing as clarity decreased. Under low clarity, blurred conditions, hearing-impaired children primarily engaged in holistic processing just as normal hearing children, but their holistic and local processing of faces of varying clarity were not as good as that of normal hearing children. This indicated that hearing-impaired children not only lacked an advantage in local processing, but also exhibited certain deficiencies.