Fig. 1.

Schematic representation of trial procedure.

An initial fixation period was followed by a boil period consisting of random, incoherent motion, which was in turn followed by a stimulus period. The stimulus period contained upward or downward coherent motion and the participant was required to report the direction using a response box. If there was no response, the stimulus remained on the screen for 2500 ms. The stimulus remained on the screen for an offset period after the response or after the maximum stimulus duration was reached. Note that arrows (indicating movement) and dotted lines (marking the square stimulus region) are presented for illustrative purposes and were not visible in the task.