Discrimination of enhanced echoes in blind and sighted individuals

Echolocation, while a useful skill for visually impaired people, is difficult to learn because humans naturally suppress environmental echoes. However, if the echoes are enhanced compared to environmentally normal echoes, they may therefore help to ease echolocation learners into the learning process. Blind and sighted participants discriminated enhanced echoes in two 2-interval forced choice (2IFC) tasks, one testing distance and the other testing left/right localization. We report that blind participants had lower left/right thresholds than sighted participants, while sighted participants had marginally lower distance thresholds than blind participants. As there is a precedent for enhanced spatial hearing in blind individuals in the literature but no such precedent in sighted individuals, we find the distance result surprising. The age and hearing abilities of our participant groups likely contribute to these results, and better-matched groups would allow us to obtain more conclusive data.