Respond only when X follows A — tests proactive cognitive control
Letters appear one at a time. You will see a cue letter, a brief gap, then a probe letter.
RESPOND (press Space or button) only when:
The probe is X and the cue was A
DO NOT respond when:
A → Y (A cue but no X probe)
B → X (X probe but no A cue)
B → Y (neither)