prosthetic memory

A pink balloon pops in front of your face -- pop -- and on a fragment of slate with a piece of chalk you write SEPTEMBER 15. A PINK BALLOON POPPED.

The next day, another balloon, a yellow one, pops in front of your face -- pop -- and on a second fragment of slate you write SEPTEMBER 16. A YELLOW BALLOON POPPED. You tuck the two fragments away in a safe in Saskatchewan.

Fifty years later, a stranger asks you which of the two colored balloons popped first, the pink one or the yellow one, and you honestly can’t recall which one it was. Then you retrieve the two fragments of slate from the safe. You read the chalk writing and confidently answer, “It was the pink one.”