A case of the blues: Why the world loses its colour when we’re sad

“Feeling blue” might be more than just a metaphor.

Indeed, how we feel about the world can play a huge role in how we see it, according to a new study in the journal Psychological Science. Feeling sad can keep us from seeing in certain colors, as though we live in Dorothy’s Kansas. But a good mood can bring those colours back into the world, just like a tornado trip to Oz.

“We were already deeply familiar with how often people use colour terms to describe common phenomena, like mood, even when these concepts seem unrelated,” the study’s lead author Christopher Thorstenson said in a statement for the Association for Psychological Science. “We thought that maybe a reason these metaphors emerge was because there really was a connection between mood and perceiving colors in a different way.”

Thorstenson was right. All it took was a clip from a cartoon to make people start seeing differently.

Participants in the study, which took place at the University of Rochester in New York, were invited to watch the two-minute scene from “The Lion King” in which heroic Mufasa is killed. To the mournful strains of Elton John’s score, they watched Simba’s eyes widen and fill with tears as he nuzzled against his fallen father. The clip - which apparently is often used in psychology studies - is scientifically proven to induce irresistible sadness at the plight of the orphaned lion cub.

Others participants were shown a clip from a stand-up comedy routine or a neutral screen saver.