This blending of the senses occurs in a rare condition called "synesthesia." In this condition, a stimulus, such as sound, creates a reaction in another sense, as well as the expected sense.
Now, professor Daphne Maurer of McMaster University's department of psychology has found that at one time we all lived in a world in which sights had sounds and feelings had taste.
Although synesthesia is thought to occur in just 1 per cent of all adults, in her keynote address at the annual meeting of the American Synesthesia Association November 6, Maurer discussed evidence that all infants are synesthetic.
"Toddlers perceive higher pitched sounds to come from white balls and lower pitched sounds to come from black balls, just like adults with synesthesia," explains Maurer. "With development, the connections underlying synesthesia are inhibited in most individuals."
People with synesthesia grow up thinking everyone perceives the world the same way they do. They discover their perception is different when they make a comment such as "she's the one with the orange name."