Colors

I've been reading Oliver Sacks books this week - I find them very insightful and entertaining. One story in particular got me excited.

This was a story about colorblind painter. Well, apparently he was not at the least colorblind for the first 40 years of his life, managed to build himself prominent career and gained some fame in his chosen profession  but then, after minor accident, lost the ability to see the colors.

 As it is further explained in the book ('An anthropologist on mars'), his 'receptors' - his eyes and his brain's ability to analyze wavelengths of colors was undamaged. However, the part responsible for 'understanding' colors, the one that allows us to recognize colors in context, the one, that apparently, lets us see red apple as red both in fluorescent lights and in the sunset (even though 'physically' we get very different wavelengths on our receptors in those circumstances) got fried.

What got me exited is that I remembered this one day when I was heavily loaded on shrooms and weed, and as I was sitting on a bench staring at the concrete pathway in front of me I realized that I can no longer tell its color or, in fact, its texture. I could not make my mind whether I see sandy path with little gentle slopes, nicely yellowish in color, only made grayish by surrounding twilight - or was it gray concrete path with little shadows from the leaves above, only made slightly yellow in color by bright night lights.

 In a moment, I could no longer tell whether I saw little twigs and pebbles lying on it or crevices and shallow depressions. I stared at the black shapes on a light background but I could no longer tell if they were shadows or some real objects, whether they had depth or none whatsoever.

 As I was trying to made my mind about this, my brain started to flash possible interpretations of this simple scene in front of me in sort of stroboscopic succession. One moment I saw a twig, the other moment I saw a crevice. The pathway was sandy, yellow, blue, gray and then pink and then gray again, in no way helping me to understand what I was seeing.
Granted, I KNEW and remembered that I was looking at concrete pathway, so in my mind I remembered it should be gray. Yet I didn't see it as gray, and what's worse, I could not decide about shadows - in everyday life shadows help us navigate the world greatly. But when 'understanding' of colors gets crazy like this, you suddenly start to mistake dark shapes on the ground for some solid objects.

 This confusion is what Sacks' patient described in detail and I was fascinated by the fact that I can now actually tell what part of my brain was most affected in that trip.
While it was fun and enlightening in many ways, I was actually relieved when this effect was gone in some 10 minutes. As my 'V3' started to operate normally I was able to stand up from the bench and continue my walk.

I am somewhat amused by the fact that now, in retrospect, having read this book, I know what was happening to me back then.