Timing of facilitatory and inhibitory effects of visual attention

Three experiments were conducted to investigate influences on the precue-to-target delay at which response facilitation is first replaced by inhibition of return (IOR). In Experiment 1, different ranges of delays were used; the interpolated delay at which faster RTs for matching precue and target locations changed to slower RTs was inversely related to the length of the range of precue-to-target delays within a block of trials. These findings were replicated in Experiment 2, which additionally showed that task difficulty provided an insufficient explanation for the delay in the changeover time. These data allowed the conclusion that a shorter range of precue-to-target delays results in later onset of IOR than does a longer range of delays. The data from Experiment 3 suggested that a single character on the target screen confounds the interpretation of possible facilitation and/or inhibition due to the allocation of attention. These results were related to other reported findings and to theories of attention allocation.