This study affirms some common observations about color perceptions and emotional states. When one is enraged, the color red appears more vivid in one’s perceptions; when depressed, the color blue. When one feels elated, all colors appear brighter, and in times of severe depression color perception can all but disappear; the world looks black and white. Or, perhaps, bleak and white.
The study attempts, and IMO fails, to attribute these things to the activity of neurotransmitters such as dopamine. But there is no finding of direct action by such neurotransmitters on the color-perceiving apparatus of the visual cortex.