Learned Responses to Targets at Subceptual Levels

Abstract

Absolute judgment was investigated as a function of light intensity subceptually and perceptually for the verbal report, GSR, and motor-conditioning systems. Training to supraliminal targets was given simultaneously to the three systems prior to the random presentation of the seven targets at seven levels of illumination for two successive tests. Thus, the size discrimination presentations were given at the detection thresholds and at three levels above and three levels below the detection thresholds for the stimuli. Subception was obtained for the verbal report and GSR systems, but not for finger movement. Judgment was apparently independent of intensity for GSR. Learning for verbal report was greater below threshold than above it, while no learning was evidenced at the detection (50%) threshold (DT). The total percentage of correct responses, however, was greater for supraliminal discrimination. Shock and non-shock targets for verbal report and GSR were differentiated more accurately at levels below awareness. The results are interpreted in terms of the central nervous system's capacity to respond to more components of the stimulus than the autonomic nervous system as well as its ability to compensate for deficits in stimulation.