I used to have a pretty sharp mind, particularly when it came to simple arithmetic. I think age has begun to dull it. Case in point: recently I had to check a friend’s pulse rate. So I felt his pulse for 15 seconds and got 17 beats. 在这一点上, I wanted to call out the heart beats per minute. And at that point, my mind suddenly went blank. It started going through this chain, “行, I got 17 为 15 seconds. So what is it for a minute? It should be, what, 60 seconds over 15 时 17. Hold it, where is my iPhone? I need a calculator. No wait, 这是 17 for a quarter of a minute. 所以 17 时 4. Where is my calculator, dammit?!” Granted, it was a slightly stressful situation. But this is not at all the way my mind used to work.
I thought back to my younger days. Say 20 或 30 几年前, if I were doing the same heart rate checking, within the first few seconds my mind would have noticed that I was getting roughly a beat per second, so the BPM was going to be about 60. In about five seconds, I would have noticed that it was going to be a bit over 60. By the tenth second, I would have known that I got between 11 和 12 beats, so the rate was going to be between 66 和 72. And by the time I got 17 beats, I would have declared 68, knowing that it was two beats over 15 per 15 seconds, so 8 beats over 60, and consistent with my earlier estimates. At the same time, my mind would have done a sort of long multiplication, “17 times four, so 40 plus seven times four, so 68 – 正确,” and a second verification, “Three under 20, so 12 下 80. 68 – correct.” All these would have happened within a half a second of completing the count to 17 beats.
So these days when people look to me for quick arithmetic calculations and estimates, I feel a bit uncomfortable. And honestly, a bit sorry for myself. It is not this aging body that bothers me. I just miss that mind I used to have.