A decision-making model based on the principle of self-control which envisages comparison of the running rate of responses with the probability of appearance of the signal as well as consecutive correction of the decision-making criterion after each response has been tested. Computer-made calculations show that subjects' activity depend on a number of non-sensory parameters - especially when sensory space is limited; this dependance is so heavy that it is desirable not to use the "Yes - No" procedure in experiments where signals have to be detected against continuous background noise. It has been shown that proper choice of the model's parameters provides good agreement between results of the psychoacoustical and computerized experiments.