Don’t You Have a Clock in Your Head?
Shane and I were in the car today, on our way home from a two-day trip. We were trying to figure out when (and where) to eat.
I said, “The GPS says we have 2 hours and 15 minutes to go. The city with all the restaurants is 45 minutes from home, and we’re going right past it. So do the math. Figure out how long it will take us to get to the restaurant.”
He did a quick calculation. “It would take one hour and 35 minutes.”
I did the calculation myself. The 35 confused me. In my calculations, it was an hour and a half away. I wasn’t as worried about his inaccuracy as I was curious about how he’d arrived at his answer. So I asked him.
“I just subtracted,” he told me. “I got 95 minutes, which is an hour and 35 minutes.”
He’d taken the number of minutes in an hour, multiplied it by 2, then added 15 to the total. Then he subtracted. He’d figured it out in just a few seconds, but it pained my brain just to think of it.
“Don’t you have a clock in your head?” I asked. Shane had no idea what I meant. So I explained that I had a visual image of a clock in my head – which, now that I’m admitting it out loud, may be kind of strange.
But my clock moves pretty easily in 15-minute increments, so I can visualize how long it will take to get from one place to another, just by “seeing” it on the clock in my head, and watching the hands go around.
Then I had a sudden, horrific explanation for Shane’s thinking.
Shane grew up on digital clocks. We do have a clock or two with hands, but for the most part, he uses clocks that display numbers only. His favorite time, in fact, is 11:11, because it is the only four-digit repetition on the digital clock. He also enjoys 1:23 and 12:34. He can’t visualize a clock with hands because he grew up on clocks without hands!
While I was realizing this, and attempting to explain it to my 21st-century son, he said, “Oh, I know what I did.”
“What you did with what?” I asked.
“I subtracted 40 minutes instead of 45,” he said. “It would take us an hour and a half to get to the restaurant,” he said.
And how long, I wonder, will it take to create an image of a clock in his head, so that he can tell time quickly and accurately without needing to figure out the numerical value of an hour?
Shane had a vision processing disorder when he was born, which continued well into second grade. I wonder if not having a clock in his head also means he doesn’t have visual images in his brain, for example, to represent words?
Maybe his visual processing screwed up the way he processes all kinds of things – and maybe he’ll never have the ability to visualize things the way I do. Maybe it’s the reason he can’t remember song lyrics, and the reason he can’t remember people’s names. Maybe he can’t visualize words in his head, which is why he can’t spell. Maybe he’s going to always have to do things in a more complex, confusing manner than most people do.
Or maybe – just maybe – he calculates time the way he does because he grew up with a digital clock.