On average, people ate less popcorn and chocolate when they were served on red plates compared to blue or white plates.
Not surprisingly, self-reported popcorn fans ate more than those who expressed no preference for it on the survey. However, these people consumed more kernels independent of plate color. When researchers corrected for people’s preferences in their statistical analysis, eating off red plates was still associated with lower consumption.
Use of the moisturizing cream followed a similar trend. When testing hand cream on red plates, people used about half as much, on average, compared to cream on blue or white plates.
Contrast had little to do with these results, said Bruno. Though dark chocolate on a red plate offered less contrast than pale colored popcorn or cream, people still took fewer chocolate chips.
“I expected to find the results related to differences in color intensity, but they did not. It’s really related to the color red compared to the food and cream colors,” he said.
The study supports the idea that the color red reduces consumption, according to Oliver Genschow, who studies consumer psychology at the University of Mannheim.
But don’t run out and buy those red plates as a holiday gift just yet. In all the research so far, participants were unaware of the real reason for the tests, implying an unconscious process may be at work.
“We don’t know what will happen if people are conscious of their plate’s color. Maybe it won’t work anymore,” Genschow said.
He says color may be an additional factor to consider when treating patients with certain eating disorders, but it’s premature to suggest everyone trying to lose weight should simply switch to red plates.
Predicting our responses to color in the real world is difficult. In other contexts, researchers have found responses to red range from attraction to aversion. On safety gauges and signs, red is a near-universal warning of danger. But on lipstick, cocktail dresses, or roses, many see red as the most romantic color.
Figuring out how colors influence our apparently spontaneous choices could eventually help design product packaging, restaurant interiors or consumer awareness programs. For now, this new study elucidates one aspect — consumption.
“People believe all sorts of things about colors and motivation,” Bruno said. “Some of these things may be true, but we need to do the science to be sure.”
Editor’s note: Jyoti Madhusoodanan is a science writer based in San Jose, California. She is a science communication graduate student at the University of California, Santa Cruz, and a reporting intern for Inside Science News Service.