The only crayons my son would use had to have the wrappers on, showing the names of the colors. I brushed it off as the peculiarities of a five-year-old, along with not letting the foods touch on his plate. Not long after, my father was diagnosed late in life as being color vision deficient. I had grown up thinking that my father simply had no interest in the color of anything. How easy it was to consider the behaviors to be idiosyncrasies rather than look for an underlying cause!