Psychopathic individuals of an excitable type and healthy subjects were examined for visual evoked potentials (EPs) of the posterior associative regions of the cortex of both hemispheres displayed upon the perception of a diffusely illuminated stimulation field ("a blank slide") presented in a random sequence and three barely distinguishable images of a male face with different emotional expressions. Three series of experiments were carried out in which instructions of various nature were used to alter selectively the significance of the stimuli presented. It was found that the organization of EPs in response to both significant and insignificant stimuli in psychopaths was different from normal whatever the conditions of the perceptive activity. The most substantial deviations were observed under the conditions of the oriented recognition of a predefined image. The psychopathic subjects exhibited no difference in EPs in response to the signal and differentiated images in the right hemisphere as compared to the healthy test subjects in whom EPs in the right hemisphere were recorded earlier than in the left one. The identified characteristic changes in EPs in the process of fine differentiation of images are indicative of the impairment of right hemisphere functions which are responsible for the differentiation and recognition of slightly distinguishable visual images.