Biocybernetic factors in Human Perception and Memory

Abstract : This project was concerned with the development of biocybernetic concepts and methods which have potential value for enhancing visual perception of, and visual memory for, scenic materials. The essence of the biocybernetic idea is that feedback and control schemes implemented by various machines can be used to enhance or extend various aspects of human performance beyond unaided limits. To design effective closely-coupled man-machine systems it is desirable to have the perceptual and behavioral aspects of human performance formulated in terms of feedback and control principles. In this project the investigators concentrated on studying the feedback and control possibilities inherent in the coupling of visual stimuli to eye-direction and to the phase of the EEG alpha rhythm. They succeeded in developing state-of-the-art systems for real-time tracking of eye-direction and alpha-phase; these computerized tracking systems are capable of controlling visual stimuli so that their occurrence is conditional upon eye-direction and alpha-phase. Their computerized eye-tracker system, known as PERSEUS, incorporates the 2-dimensional double-Purkinje-image eye-tracker (DPIET) developed at the Stanford Research Institute. This non- contacting device tracks and compares the positions of the first and fourth Purkinje images formed by reflections of infrared light beamed at the subject's eye. By comparing the position of the fourth Purkinje image with respect to the first Purkinje image, one obtains a sensitive measure of eye-rotation which is uncontaminated by eye-translation. A computerized scheme was implemented for the phase-contingent analysis of the average visual evoked potential.