For Arguments and Rational Decisions, Turn Down the Lights

If you need to make a big decision and want to make it without much emotional baggage, a new study shows that you might want to turn down the lights.

Alison Jing Xu, assistant professor of management at University of Toronto Scarborough and the Rotman School of Management, along with Aparna Labroo of Northwestern University, experimented with the relationship between lighting and human emotion. They found that human emotion, whether negative or positive, is felt more intensely under bright light, according to a press release announcing the findings.

"Other evidence shows that on sunny days people are more optimistic about the stock market, report higher wellbeing and are more helpful while extended exposure to dark, gloomy days can result in seasonal affective disorder," said Xu.

"Contrary to these results, we found that on sunny days depression-prone people actually become more depressed," she said, pointing to data showing suicide rates peaking during late spring and summer.

During the experiment, XU and Labroo asked participants to assign ratings to a wide variety of thing, including "the spiciness of chicken-wing sauce, the aggressiveness of a fictional character, how attractive someone was, their feelings about specific words, and the taste of two juices," while being exposed to different lighting conditions.

Their results show that participants were more likely to give more "intense" rating while under brighter light conditions. Under bright lights, the study participants preferred spicier sauce, thought fictional characters more aggressive or other people more attractive. They drank more of the "good" juice and less of the "bad" juice while ranking works closer to the extremes of the rating spectrum.

Xu said that bright lights might act like heat, the perception of which can trigger our emotions. "Bright light intensifies the initial emotional reaction we have to different kinds of stimulus including products and people," she said.

The connection between light and emotions means that rational decisions or logical debates will fare better in a dim setting.

"Marketers may also adjust the lightening levels in the retail environment, according to the nature of the products on sale," said Xu. "If you are selling emotional expressive products such as flowers or engagement rings it would make sense to make the store as bright as possible."

The research is published in the Journal of Consumer Psychology.