Related Experiment Video
Updated: May 18, 2026

Measurement of Neurophysiological Signals of Ignoring and Attending Processes in Attention Control
Published on: July 5, 2015
The phenomenology of attention. 2. Brightness and contrast
W Prinzmetal1, I Nwachuku, L Bodanski
1Department of Psychology, University of California, Berkeley, Berkeley, California, 94720, USA. wprinz@garnet.berkeley.edu
Abstract:
The effect of attention on perceived brightness and contrast was investigated in eight experiments. Attention was manipulated by engaging observers in an attention-demanding concurrent task (letter detection) or by directing attention to a location with a peripheral cue. In all of the dual-task manipulations, attention reduced the variability of responses. However, attention did not affect the brightness of stimuli, nor did it affect the amount of simultaneous brightness contrast. Results with peripheral location cues were similar; however, the effect of attention in these experiments could be attributed to nonperceptual factors. The metaphorical "spotlight" of attention reduces observers' uncertainty about the brightness of a stimulus, but it does not "illuminate" in terms of brightness or contrast.
Related Concept Videos
Vision
Anatomy of the Eyeball
Focusing of Light in the Eye
Perception
Bottom-up processing begins at the sensory level, where receptors detect external environmental stimuli. These could include the tactile sensation of...
Gestalt Principles of Perception
Perceptual Constancy
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...

