In psychiatry, as in other fields of medicine, the beginning of clinical science is the collection of observable data and the study of their interrelational patterns. The second step is methodical observation, utilizing specific means to extend and focus the scope of the observation in the experiment. Further development brings out the neurophysiological and neurochemical basis of psychiatry. The different conditioning techniques are specific means that enable us to add further, qualitatively different observations to enlarge our understanding of psychiatric conditions. One of the most widely used conditioning techniques employs galvanic skin resistance (GSR) as a measuring device. In the conditioning procedure, an indifferent conditional stimulus is associated with a specific unconditional stimulus. After several associated administrations, the formerly indifferent stimulus is tried alone, and, if conditioned, it results in a skin resistance decrease. A technical advance, polygraphic instrumentation, made it possible to have simultaneous recordings of several conditioning aspects of the organism.