Drescher, V. M., Whitehead, W. E., Morril-Corbin, E. D. et al. 1985. Physiological and subjective reactions to being touched. Psychophysiology 22, 96-100.

The physiological and subjective effects of being touched on the wrist by another person were investigated in 20 normal adults at rest and during immersion of the hand in ice water. Touching reliably reduced heart rate compared to an immediately preceding baseline and compared to an alpha biofeedback condition. Heart rate during painful ice water stimulation was also lower when the subject was touched as compared to when he/she practiced alpha biofeedback, but this effect was not mediated by a reduction in the perceived painfulness of the ice water. Instead, touching and pain had independent, additive effects on heart rate. Touching did not produce generalized reductions in respiratory rate, SRR frequency, or frontalis EMG activity, although subjects did rate being touched as more pleasant and more relaxing than practicing alpha.