Horsetalk's crazy world of horses

Researchers no doubt find it frustrating when their subject loses motivation - and that applies even when your subject happens to be a horse. Swedish researchers exploring night vision in horses struck exactly that problem with Rex, one of three horses trained to choose between two colours in front of him. Whenever Rex chose green in the series of tests he was rewarded with carrot pieces. The scientists then began dimming the light to test Rex's night vision. However, the researchers said at lower light intensities, "Rex totally lost the motivation for the experiment, and after that chose randomly even in tests in brighter light". Read more on the study here.