Kleurstimulus

Kleurstimulus (Dutch for "color stimulus") is a visual stimulus defined by color properties that is used to elicit perceptual, cognitive, or motor responses in experiments. In Dutch psychology and neuroscience literature, the term denotes any stimulus whose primary salient feature is color, as opposed to form, motion, or luminance alone.

Color stimuli are characterized by hue (the type of color), saturation (intensity of color), and brightness (lightness). Researchers specify colors using standardized color spaces such as CIE 1931 XYZ or CIE L*a*b*, enabling precise replication and perceptual comparison. Luminance matching is often crucial so that differences in responses reflect color perception rather than brightness.

Color stimuli are used across domains: in basic vision research to map responses of cone pathways and color-selective areas of the cortex; in conditioning and attention experiments as cues; in psychophysics to measure color discrimination thresholds and afterimages; and in neuroimaging to study color processing in the visual cortex. They can be presented on computer monitors, projectors, or physical patches and may be paired with rewards or tasks to study learning and memory.

Limitations and considerations include perceptual variability due to color vision deficiencies (e.g., red-green color blindness), aging, and individual differences in color naming. Accurate presentation requires calibrated displays, controlled lighting, and attention to surround colors, as context can affect color perception.