Gus is learning his colors. That is, he’s learning the English words for two of the colors that equids are known to see clearly: blue and yellow. (Dissecting a horse eyeball, so I gather, is all it takes to see what kinds of rods and cones are inside, and the cones for blue and yellow far outnumber those for green and red. If you stand in a bright-green field wearing a bright-red sweater, your horse will think you disappeared in a vast, undifferentiated grey fog.)
The colors lesson is dead simple, but it requires approximately 7,342,694 repetitions. I make a start by holding up a cardboard square that I painted blue, and Gus naturally touches it. I click and treat, and I do it again. Eventually I say “blue” when I offer it to him. I do this again. And again. After a couple of five-minute sessions over a couple of days, I bring out a yellow-painted square and get him to touch it as I say “yellow.” Again and again. My eyes are crossing, but Gus never gets bored — this is the easiest way to earn treats, ever!
Now we start the actual learning: I have a yellow square in one hand and a blue in the other, and I hold them both up while saying either “blue” or “yellow.” Now he has a choice, and one touch will earn him a treat but the next might get him bupkus. “What is the meaning of this?” he demands. I randomly switch the colors I say, and I randomly switch which hand holds which color. I randomly raise the cards higher and lower. Next I do the same with blue and yellow cardboard circles. Lately I'm doing it with little plastic cones; next I'll use washcloths or cups . . . He’s got to figure out what one criterion I require for granting him a click: is it about my left or right hand? is it about the item’s shape? is it about where we are in the arena? Once he can rule out the circumstantial variables, he’ll discover that the key, the only key, is the color. And that the human-voice sound “bloo” or “yell-oh” signifies the color. And so, more repeats. We must be at several hundred by now; only a few million still to go.
Gus gets that two is an easy number: after a wrong choice, if I hold the same cards in the same hands next time, the only right possibility is the choice he didn’t make last time. What stumps me is why he occasionally rejects this logic and keeps choosing the wrong card three or four times in a row. Is he suffering an epileptic or Tourette’s spasm that fixates him on the same wrong color? Does he think it’s fun to insist on a mistake just to switch up the game? Once or twice, after denying him a click for several errors, I take pity and hold the correct card closer to his nose, to make sure he’ll finally get it right. Often, though, I can change hands and verbal cues all over the place, and he’s unfazed, getting it right every time. Until, for some reason, he just blows it. No matter — he’s inching his way to maybe 75% correct, and he loves, loves, loves the game.