Increasing intensity directly increases the perceived warmth of primary colors

Area of Science:

• Psychology
• Color Science
• Sensory Perception

Background:

• The hue-heat hypothesis posits a link between color and perceived temperature, with red and yellow typically seen as warm, and blue and green as cool.
• Previous research often used broad-band light at fixed intensities, potentially limiting understanding of color-temperature relationships.

Purpose of the Study:

• To investigate if increasing the intensity of highly saturated primary colors alters their perceived temperature.
• To examine the quantitative relationship between light intensity (luminance) and perceived color temperature.

Main Methods:

• Twenty healthy young adults with normal color vision participated.
• An optical system presented four primary colors (blue, green, yellow, red) at five intensity levels.
• Participants rated perceived temperature on a scale from -5 (coolest) to +5 (warmest).

Main Results:

• Blue and green were perceived as cooler, while yellow and red were perceived as warmer, consistent with the hue-heat hypothesis.
• Perceived warmth significantly increased for all colors as light intensity increased.
• Linear regression models showed strong correlations between luminance and perceived temperature for each color (r² values ranging from 0.78 to 0.98).

Conclusions:

• Color significantly influences temperature perception, supporting the hue-heat hypothesis.
• Increasing the luminance of colors intensifies the perception of warmth across the spectrum.
• Luminance is a critical factor modulating the color-temperature relationship, extending previous findings.