Elmer Green of the Menninger Institute explains the scientific rationale of biofeedback, and how feeding back information from inside the skin enables people to develop voluntary control of formerly involuntary body processes. Thus with the help of modern technology, ordinary people can learn to make many of the same physiologic changes as advanced Yogis such as Swami Rama, who in the film performs such feats as stopping his heart and reporting words spoken in a room while he is asleep. Elmer, Alyce, and daughter Judy take a portable psychophysiology lab to India to study yogis’ physiological state.