How do normal subjects learn a simple adaptative task: how and why do paranoid schizophrenic patients fail?

The authors studied the behavior of normal subjects and paranoid schizophrenic patients in a simple problem-solving situation. The schizophrenics were divided into two sample groups, one of individuals under treatment and the other of individuals not under treatment. The learning process involved in this problem-solving situation is very similar to an instrumental conditioning, and can be understood by means of the following assumptions: (1) the subjects use decision functions in reacting to the stimuli, although they may be not fully aware of this; (2) learning is the result of successive transformations of these decisions in the course of time; (3) the changes have specific probabilities and are related to (a) those responses which are made to the latest stimuli, and (b) a differential probability for decision functions which were effective, or only interrupted painful reinforcement, or were completely ineffective. In schizophrenics further factors of importance were (1) an 'inertia' factor and (2) the rigidly continued use of unsuccessfuly or only partially successful decision criteria. The authors used a systems theory based on Galois field theory and a calculus of operators specifying three groups of subjects. A computer program based on thses hypotheses was tested in a stimulation experiment. The statistical evaluation of the results showed a congruence between the theoretical approach and the experimental data.