Seeing red? The mind-bending power of colour - Telegraph

“'The whole point of colour vision is not to inspire poets, but to allow contrast detection,' says Russell Foster, professor of circadian neuroscience at the University of Oxford. 'You’ve got a much better chance of detecting an object against a background if you have colour vision.' Birds are the masters at this, he says – they are tetrachromatic, having four colour detectors, and would see things that we see as a single red as an infinite, glorious wash of colours."