Evoked potentials and sensation

Objective physiological measurements (evoked potentials) were compared with the corresponding psychophysical observations for human Ss. Discrepancies were found between the amplitude of the steady-state evoked potential (EP) and the sensations of flicker produced by visual stimuli of different modulation depths. Poor correlations were also found between subjective De Lange curves and amplitude vs frequency curves for the EP under conditions of chromatic adaptation. It is suggested that two classes of EP can be distinguished; one correlates well and the other correlates poorly with sensation.