Enhanced auditory serial recall of recently presented auditory digits following auditory distractor presentation in blind individuals

The ability to focus on task-relevant information while ignoring distractors is essential in many everyday life situations. The question of how profound and moderate visual deprivation impacts the engagement with a demanding memory task (top-down control) while ignoring task-irrelevant perceptual information (bottom-up) is not thoroughly understood. In this experiment, 17 blind individuals, 17 visually impaired individuals and 17 sighted controls were asked to recall the sequence of eight auditorily presented digits. Following digit presentation, two auditory distractor streams including a repetitive presentation of the same syllables (steady-state sounds) or different syllables (changing-state sounds) occurred spoken in different emotional prosodies (happy, fearful, angry, and neutral). Blind individuals not only showed overall superior serial recall performance but also displayed sustained memory retention for items presented more recently in the sequence (specifically at the fifth to the eighth digit positions) compared with sighted and visually impaired individuals. Furthermore, blind individuals showed a weaker serial position effect compared with visually impaired and sighted individuals. Emotional prosody also impacted serial recall differently in blind, visually impaired and sighted controls: Sighted and visually impaired participants exhibited improved serial recall when steady-state sounds carried a fearful or angry prosody. By contrast, in the steady-state condition, emotional prosody had no effect on serial recall performance in blind individuals. These findings may be linked to the enhanced ability of blind individuals to flexibly apply a combination of strategies, such as association and grouping.