Abstract: Two experiments are reported that examine the effects of practice on the early facilitation and later IOR effects of cueing, in a detection and a color-discrimination task. In the first experiment a short and a long SOA were mixed within a block of trials, so that there was temporal uncertainty, whereas in the second experiment SOA was manipulated between subjects, to eliminate temporal uncertainty. Facilitation and IOR effects were obtained in the short and longer SOAs respectively, in both detection and discrimination tasks, and they consistently decreased with practice. The cueing effects were more positive (bigger facilitation and smaller IOR) in the discrimination task than in the detection task. Cueing and practice effects were modulated by temporal uncertainty (Experiment 1 vs. Experiment 2).

(1998). Perception & Psychophysics, submitted.