Light can affect people's mood and behavior. The Daily Mail reported that a new study published in the American Journal of Consumer Psychology found that people's emotional reactions are stronger in strong light and milder in dim light. If couples dim the lights before talking, the chances of quarreling will be greatly reduced.

Under normal circumstances, ordinary people can decide how much they should say according to each other and external conditions, especially for those who don't know each other very well but are willing to continue their contacts. They feel alert and naturally try their best to show their good aspects and hide their weaknesses and shortcomings as much as possible. Therefore, it is relatively difficult for both parties to communicate at this time. When darkness comes to the scene and the other person's senses fail, he has no danger, no need to disguise, no need to arrange expressions, and naturally show it; When a person's senses fail, he becomes fragile and sensitive, and tends to grasp the sense of security of his companions in the dark. This kind of adsorption is very strong. Thus, the dark effect was produced.

Psychologists say that the "dark effect" can also explain why strangers are more likely to meet and even fall in love in dimly lit bars and dance halls than in ordinary occasions. The reason is that too bright light will make it difficult for people to relax, thus improving their vigilance and alertness.