Fig 1. Trial design for the pain anxiety task.

Note that although the duration of the stimulus in Fig 1 is listed as four seconds, this includes one second for the thermode to increase from the baseline temperature to the target temperature, and an additional second for the thermode to return to the baseline temperature following the two second application of the stimulus at the target temperature. A 0.5s ‘beep’ signalled the commencement of thermal stimulus delivery. After each stimulus was delivered participants were prompted to provide ratings of anticipatory anxiety, pain intensity, and pain unpleasantness.