Fig. 1.

Paradigm. A: main experiment. In the Pain & Buttonpress condition, 60 heat stimuli of increasing intensity were applied to the dorsum of the left hand. Participants were instructed to press a button with the right index finger to stop the stimulation at the maximum pain intensity they were willing to tolerate. In the Buttonpress condition, participants were instructed to perform button presses at about the same interval as in the Pain & Buttonpress condition but without concurrent painful stimulation. B: control experiment. In the Warmth & Buttonpress condition, participants were instructed to interrupt the increasing thermal stimulation when it was perceived as clearly warm. The Buttonpress condition matched that of the main experiment.