The number purple Synaesthesia is a strange condition in which sensory inputs to the brain seem to get muddled so that people claim, for example, that they "see" a particular colour when shown a particular number. Because each person with the condition names different colours in association with different numbers, some psychologists have doubted how fundamental the effect is. Now there's a new test which strongly supports the view that people with synaesthesia really have their "wires crossed". http://www.newscientist.com/nl/0408/purple.html