Mind machines: a controlled study on the effects of electromagnetic and optic-acoustic stimulation on general...

Mind machines are said to induce relaxation and an altered state of consciousness. The influence of optical-acoustic (OAS) and electrical stimulation (ES) mind machines on general well-being, electrodermal activity, and altered states of consciousness was investigated and compared with pure rest and a placebo. Thirty participants underwent 4 conditions in random sequence: rest, placebo stimulation, OAS, and ES. Statistical evaluations before and after the experimental stimulations showed differences in general well-being and electrodermal activity measures but no between-conditions effect. ES and OAS produced significantly more visionary experiences and fear of ego dissolution than rest and placebo. Differences in mystical experiences were found between ES and OAS. Mind machines do not have a specific effect on general well-being and physiological relaxation, although they may produce unusual psychological experiences; people with psychiatric illnesses should not use such devices.