Fig. 4: Illustration of the four cognitive tasks.

a Spatial n-back Task; (b) Face Identification Task, which used face images sourced from Set A of the Karolinska Directed Emotional Faces dataset86 (placeholder images are displayed in the figure rather than the actual stimuli); (c) Expression Recognition Task, which used face images sourced from the RADIATE database91,92 (placeholder images are displayed in the figure rather than the actual stimuli); (d) Psychomotor Vigilance TaskāPsychomotor speed trials; and (e) Psychomotor Vigilance Taskāsustained attention trials. The screens shown are for illustrative purposes only; refer to the text for the actual stimuli sizes and on-screen locations.