Colour-in-Context Theory
Colour is a signal, and a signal means nothing outside a setting. The claim is not that a colour produces an effect, but that it carries whatever meaning it has acquired where the person happens to be standing.
What it is
Red is the colour of a ripe fruit and of the mark on a failed exam paper. Any theory treating those as the same signal is in difficulty from the start, so the framework predicts opposite effects in the two settings and expects them to operate without the person noticing.
Andrew Elliot built the case in 2007 on test performance, reasoning that in a room where you are being assessed red carries the association of the failing mark and should tip a person towards avoidance. Four experiments found impaired performance; two more looked for avoidance in task choice and in cortical activation and reported signs of it in both.