The detectability of a brief color shift towards red or towards green of a foveally viewed yellow target is less by 25% if the observer is uncertain as to the direction of the color shift. This result matches a prediction of the theory of signal detectability: When signal parameters become uncertain, detectability declines.
Time-averaged human electroretinogram (ERG) responses were determined for several workplace visual stimuli which are temporally modulated at rates exceeding the perceptual critical fusion frequency (CFF). A clearly identifiable synchronous response was in evidence for a video display terminal (VDT) stimulus operating with a refresh rate as high as 76 Hz. A… (More)
Saccadic suppression is a decline in detectability of a weak flash presented during a saccadic eye movement. We examined the hypothesis of Matin [Psychol. Bull. 81, 899 (1974)] that saccadic suppression may be due to increased stimulus uncertainty during the saccade. Uncertainty could arise from variability and inhomogeneities in the visual frame of… (More)
The pupil oscillates in synchrony with a slow beat produced by adding two lights flickering at slightly different frequencies. This behavior shows that nonlinear processes are present within the pathway. To localize these processes, a light of one frequency was presented to one eye, while a light of a different frequency was presented to the other. No pupil… (More)
We employed vertical sinusoidal test gratings to search for spatial adaptation to lower-case text presented on a standard video display terminal. The parameters of the contrast sensitivity test were selected on the basis of waveform analysis of horizontal spatial luminance profiles of the text. We found that subjects exhibited a small (4-5 dB), but… (More)
A limited set of illuminants and phosphor colors are commonly used in video display terminal (VDT) working environments. This study attempts to identify any combinations of such conditions that influence performance on a visually demanding counting task. Experiments were performed to test whether the phosphor color, ambient lighting spectrum, or temporal… (More)