In a 2007 experiment in New York City dubbed the “cocktail party study,” researchers divided party-goers into red, blue or yellow rooms. Guests in the yellow room ate—get ready for this—twice as much as the others. As well as stimulating appetite, yellow also stimulates the mind and intellect, making it a good pick for offices and anywhere you do homework or study, says McLeod. A 2010 study in the journal BMC Medical Research Methodology found that yellow was the color most often associated with a normal mood, and grey with an anxious or depressed mood. Add a dash of green, however, and you’ve got the color a University of Georgia study found evoked the least positive responses in students: yellow-green was associated with vomit and disgust.