Visual Masking in prolonged wakefulness

The aim of the present study was to evaluate the effect of sleep deprivation on object substitution masking (OSM). Since both automatic and voluntary shifts of attention toward the mask are involved in OSM, and sleep loss affects voluntary spatial orienting, we expected OSM to be affected by moderate (24h) sleep deprivation. Results showed a small but robust reduction of OSM confirming the involvement of voluntary attention in OSM, but suggesting that it is mainly due to automatic attention. Results also confirmed that sleep-deprived individuals may adopt an automatic, instead of voluntary, modality of control.