Time course of location-cuing effects with a probability manipulation

A location-cuing paradigm was used to study the effects of cue probability on the allocation of visual attention. A cue was used to indicate the likely location of a target (out of 4 possible target locations), with 8 cue-target onset intervals, ranging from 0 to 233 ms. There were 3 blocked proportions of correctly cued trials, 100%, 75%, and 50%. The observers had higher target discrimination accuracy at highly probable locations than at less probable locations, and these differences were maintained across all cue-target onset intervals. Thus, it appeared that the observers were allocating attention as a function of cue probability, with a consistent pattern throughout the time course of the development of attention. The consistent pattern across stimulus onset asynchronies (SOAs) suggests that the effects of time after cue and the effects of probability may rely on independent processes.