In case of biofeedback, there are a number of techniques that can be used, but the most
basic one is-to attach a GSR device to the person's fingertips. This measures the galvanic
skin response, or minute amounts of perspiration on the skin. The more tense you are, the
more perspiration there is on your skin. As you become calm, there is less and less.
The electrodes are attached to a machine which converts the electrical information into
an easily observable form, such as a light or a buzzing noise. The machine can be
adjusted, so that the buzzing sound is moderately audible at the beginning of the session.
As the device picks up more perspiration, meaning more tension, the noise gets louder. If
the person becomes calmer and there is less perspiration, the noise becomes lower and is
Usually, the person hooked up to the biofeedback machine and told extinguish the buzz
or the light. Since the person has no idea what to do, he or she will start
to stop the annoying sound. If he tenses his muscles, for example, he will find that the
noise is getting louder. Then, maybe he figures that if he relaxes, the buzz will go
softer. So. he relaxes and the buzz does get softer. But it is not extinguished.
The person now will start putting himself/herself in various frames of mind that he believes
will do the trick. There is a delay of several seconds between the feeling and the buzz,
because it takes that long for the perspiration to appear on the skin, but he will soon
enough find out if the machine is doing what he wants it to do. He tries other frames of
mind. He imagines different scenes, different people, maybe different colors. Then, quite
suddenly, he discovers that the sound is no longer there. He will start mentally examine
what he did to get to that condition. In practice, he will recall it and keeps it up.
The therapist will now readjust the machine so that it has greater sensitivity. In
other words, the buzz is going to sound when smaller amounts of perspiration are detected.
In another session or two the person would probably learn how to counter this, and the
process is continued until a satisfactory degree of relaxation is obtained. Once the
person figures out how to do it with the help of machine, he can accomplish relaxation
without the help of the machine by doing what he had to do as learned from the biofeedback
The same technique would be used to teach someone how to warm his hands, such as when
we want him to control his migraine headaches. Here, instead of measuring perspiration,
skin temperature would be measured. The person would imagine whatever he found necessary
to do the trick. Incredibly, some people can not only boost the temperature of one hand
over the other, but also to make one part of their palm warmer than the adjacent