Sensitivity of the auditory system to differences in intensity : temporal transfer and difference limen studied in psychophysical experiments : recording and analysis of evoked potentials

An important property of the auditorv system is the way this system processes changes in stimulus intensitv. Although this problem has been discussed manv times since Weber, it is rather surprising that no generally accepted hypothesis about the underlying mechanism has emerged. In the nresent study the sensitivity of the ear to intensity differences of noise signals is studied. In general two methods of investigation are used for the study of perception: nsychophysics and electrophysiology. Fechner founded psychonhvsics in 1860 ( Boring, 1950, 1966) as a studv of the relation between stimulus and sensation. In psychophysical experiments a stimulus is presented, and an observer makes some response (either by saying or by pressing a button). The system to be studied contains the peripheral sense-organ as well as the neural pathways that processes the information elicited in the peripheral organ. Considering the stimulus as the input of the system and the response of the observer as the output, it is possible to measure input-output relations by varying the parameters of the input stimulus. The investigator makes assumptions about how the system functions, and these assumptions have to account for the inputoutput relations. All the assumptions together constitute a model. Such a model of the system can suggest new experiments, and the results of such experiments lead to refinement or rejection of the model. Psychophysical experiments can never prove, however, that the system works like the model.