Posted by: Alexandre Borovik | October 26, 2011

The Grapes of Math, homeschooling and EU disability legistation

In the  Math Future weekly series, today’s event is a webinar with Greg Tang, a popular book author and game designer. The advert says:

Ten years ago, Greg Tang was looking for a better way to teach math to his kids. He wound up creating a groundbreaking series of picture books that included the New York Times best seller The Grapes of Math. His books quickly became staples in school libraries and university teacher training programs, garnering numerous awards and selling over a million copies. The free online version of The Grapes of Math.

The Grapes of Math is indeed a lovely book, and immediately raises a very interesting question: it uses colour coding of information, which appears to be forbidden in the institutional use in this country by law (adopted from the EU legislation), and, I have to agree, for good reason: 1 person in 20  is colour blind or have significant deficiency of discrimination of colours. American homeschoolers, if their children are not colour blind, can of course ignore this issue and use colour coding, a powerful didactic tool. But I, as a lecturer to a class of 280 students, cannot ignore the issues of equality of access: 1 in 20 for me means 14 students, I cannot damage their chances to learn.

By the way, the Wiki article on colour blindness contain some tantalising snippets:

About 8 percent of males, but only 0.5 percent of females, are color blind in some way or another, whether it is one color, a color combination, or another mutation. […]

Any recessive genetic characteristic that persists at a level as high as 5% is generally regarded as possibly having some advantage over the long term, such as better discrimination of color camouflaged objects especially in low-light conditions.[2][10] At one time the U.S. Army found that color blind people could spot “camouflage” colors that fooled those with normal color vision.[11][not in citation given][12]


  1. Alexandre, interesting point – I will ask Greg today about it. There is a test applet a non-color-blind person can use to see if color-blind people will distinguish a given set of colors – if the colors are different enough. There are lists of accessible color choices you can use for coding and still be within the accessibility regulations. Or you can make values different in addition to colors (that’s what happens with camouflage, I bet).

  2. I wish legislation like that were more flexible. Couldn’t we use color for the 92%, and then present a similar min-lesson using another pedagogical device that maybe wouldn’t work as well for a different 8%?

    We cannot legislate equal responses to our presentations, and it seems limiting to avoid good instructional strategies because a few people can’t engage with them. It would be wiser (imo) for the legislation to say something like… always present material in another way when you use uncaptioned videos, or color.

  3. It would be interesting to see if the proportion of professional mathematicians who are colour-blind is less than the proportion of colour-blind people in the general population as a whole. In other words, is there any evidence that colour-blindness has actually impeded any intelligent, would-be mathematicians from pursuing careers as mathematicians? Certainly, for most of the last 400 years, mathematical books and journals were printed only in black and white, so it is hard to imagine that colour-blindness actually prevented anyone being a great mathematican.

  4. Its not that colour coding is illegal. What is at issue is where colour coding is the ONLY form of coding the information. It is perfectly acceptable – even good practice – to use multiple ways of coding information so that people with different abilities or aptitudes can use any of them; and that for most they reinforce.

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