Space and time modulate faster visual detection in the profound deaf

Previous literature suggests enhanced visual skills in profound deafness. We examined visual detection and discrimination abilities in profound deaf and hearing controls, as a function of target occurrence in time and space. Modulations in time were obtained by presenting visual targets at one of two intervals after a warning signal: 600ms ± 200 (short interval) or 2000ms ± 200 (long interval). For half of participants, short intervals were standards (i.e., 84% of trials) and long intervals were deviants (14%); for the remaining participants standard/deviant proportions were reversed. Modulations in space were obtained by presenting targets at one of two eccentricities: 3 or 8 degrees. In Exp.1 (detection) profound deaf were overall faster (40ms on average) than hearing controls. Reactivity enhancements were mostly pronounced for targets occurring at short interval and towards the periphery. In Exp.2 (discrimination) faster responses only emerged at the expenses of accuracy. Moreover, no modulation of visual responses emerged as a function of time and space. We suggest that reactivity may be a core aspect of deafness, and it can be modulated as a function of space and time. However, reactivity may reflect faster transmission of visual input (or motor preparation) than enhancement of late perceptual processes.