Turn the lights down to avoid a row: Hitting dimmer switch could stop disagreements escalating, research suggests Bright lights intensify perceived aggression, scientists found Thought brightness affects feelings as they increase perception of heat By Sophie Freeman Turning the lights down first could make difficult conversations with your other half easier as our emotional responses are stronger under bright lights, research shows Ladies, if you need to have a difficult conversation with your other half, try turning the lights down first. Our emotional responses are stronger under bright lights - so hitting the dimmer switch could stop a disagreement escalating into a row, according to new research. A study by the University of Toronto and Northwestern University found that bright lights intensify perceived aggression in others as well as increasing how emotionally-charged we perceive their words to be. Participants were asked to carry out a series of tasks, with half assigned to a brightly-lit room and half assigned to a dimly-lit room. In the first experiment, the two groups were asked to watch a video of a pretend TV advert in which a fictional character engaged in a series of potentially aggressive behaviours because he was late for work. Those who watched the video in the brighter room rated the character as more aggressive than those who watched the video in the darker room. In a second experiment, another two groups were asked to report their feelings towards positive, negative and neutral words. Those in the brightly-lit room rated the positive words, such as flower and smile, more positively, and the negative words, such as dentist and medicine, more negatively, than those in the dimly-lit room. As expected, there was no difference in how the neutral words were perceived. The researchers, writing in the Journal of Consumer Psychology, proposed that bright lights affect our feelings because they increase the perception of heat. Perception of heat turns on the emotional system, intensifying a person's initial emotional reaction... we propose that because people almost always experience light along with heat, this connection between light and heat may be deeply rooted psychologically. To test their theory, the researchers asked the groups how warm they felt in the two separate rooms. The temperature in both rooms was the same, but those in the brighter conditions reported feeling warmer in than those in the dimly-lit room. Scientists believe bright lights affect our feelings because they increase the perception of heat (library image) The researchers said: "Though people see with their eyes, being in light can influence their heart. We found light increases people's perceptions of ambient warmth, which in turn activates their hot emotional system, leaving to intensified reactions - positive and negative - to different kinds of stimuli. Light can influence a wide range of judgments that are not obviously or directly related to it. They concluded: "These findings suggest a simple way to nudge people into being less emotional - by simply turning the lights down." The results support previous studies which have found that on sunny days, happy people tend to feel happier, while depression-prone people feel more depressed.