Fig. 2.

All trials began with presentation of the neutral warning stimulus. In stimulus trials, this was replaced 800, 1000, 1200, or 1400 ms later by onset of the movement stimulus, which was of 480 ms duration. After the imperative stimulus action, the screen went black for 3000 ms before the warning stimulus for the next trial appeared. In catch trials, the warning stimulus remained on the screen for 1980 ms before the 3000 ms inter-trial interval. Participants performed a pre-specified action in each block. In blocks where participants were required to lower their eyebrows, this would be a compatible trial, and in blocks where they were required to raise their eyebrows, this would be an incompatible trial. Order of response actions was counterbalanced across participants.