Perceptual Sensitivity to Tactile Stimuli Is Enhanced When One Is Aware That Tactile Stimulus Intensity Is Self-Controlled

The stimulus intensity at the perceptual threshold, when controlled by the participant, was significantly lower compared to when controlled by someone else, regardless of visual availability. This indicates that awareness of the self-control of the tactile stimulus intensity enhances tactile sensitivity. The electrodermal level immediately preceding the stimulus at the perceptual threshold was significantly lower when the participant controlled the stimulus intensity compared to when it was controlled by someone else, with eyes closed. The electrodermal levels immediately before the perceptual threshold stimulus, when triggered by another person, were significantly higher with the eyes closed. These electrodermal findings suggest that cognitive stress is greater when the timing of the initial tactile perception is difficult to predict.