The effects of endogenous and exogenous spatial cueing in a sustained attention task

Sustained attention decrease over time has been ascribed to an impairment of attentional top-down processes, but this hypothesis was never experimentally evaluated. In order to differentiate involvement of both endogenous and exogenous processes in the decrement of sustained attention over time, we proposed a new paradigm that is a combination of the X-Type Continuous Performance Task (Rosvold et al., 1956) and the Spatial Cueing paradigm (Posner, 1980). This task allow us evaluation of two different stage of processing: the orienting stage and the sustained attention stage. Two experiments were proposed, both having two type of spatial cue: one with an exogenous cue, and the other with an endogenous one. We expected performance in the endogenous condition to be more vulnerable to deterioration. The preliminary analysis on 12 subjects showed a RT increase over time only in the endogenous cueing task (F3,21=5,85; p<.004), but no effect in the exogenous cueing condition (F3,30