Mackworth clock test (Sustained attention task)

This vigilance task was developed according to the description of the task used by Kilpelӓinen, Huttunen, Lohi, and Lyytinen⁴¹. The task was a modified version of the Mackworth clock test with parameters adapted from Teikari⁴² and ran on a standard desktop computer. The participant was presented a visual display with 16 hole-like black circles arranged in a clock-like figure against a black background. Each circle changed from black to red for 0.525 sec in turn, with each cycle lasting 3 sec. The red light moved in a clockwise sequence by one step, which was considered the normal stimulus appearance. When the light moved twice the usual distance (i.e., skipping a circle), it was considered a critical signal, and the participant was required to respond to this signal by pressing the spacebar as fast as possible on the keyboard with his or her preferred index finger. Participants performed this task for 30 min every session. Twelve critical signals occurred at randomized times within each session.