Color as a Tool

Anne is reading a book called My Stroke of Insight, in which neuroscientist Jill Taylor describes her massive left-hemispheric stroke and subsequent recovery. At one point Jill’s mother is helping with the rehab by having Jill work on crossword puzzles:

“My right hand was extremely weak so just holding the pieces and making comparisons took a lot of effort. Mama watched me very closely and realized that I was trying to fit pieces together that obviously did not belong together based upon the image on the front side. In an effort to help me, G.G. noted ‘Jill, you can use color as a clue.’ I thought to myself color, color, and like a light bulb going off in my head, I could suddenly see color! I thought, Oh my goodness, that would certainly make it much easier! I was so worn out that I had to go to sleep. But the next day, I went straight back to the puzzle and put all the pieces together using color as a clue. Every day we rejoiced what I could do that I could not do the day before. It still blows my mind (so to speak) that I could not see color until I was told that color was a tool I could use. Who would have guessed that my left hemisphere needed to be told about color in order for it to register?” (p. 99)

Neurological research has demonstrated that the right brain is dominant in color detection, but the left brain controls systematic problem-solving tasks. The implication is that, while this person’s intact right hemisphere could see color even after the stroke, her damaged left hemisphere didn’t remember how to use color pragmatically in solving the puzzle. Based on this self-report we infer that her brain injury severed the unconscious connection between sensation and perception, between the ability to pick up information from the environment and the ability to make sense of that information. She said that, when someone suggested that she use color intentionally as a clue to assembling the puzzle, she could “suddenly see color.” She must have retained the ability to sense color: just knowing that color could potentially be useful wouldn’t help a colorblind person solve the problem. However, since she couldn’t figure out how color contributed to her understanding of the world, from a practical point of view she might just as well have been colorblind.