Mind Hacks

Hack #35. Count Faster with Subitizing

You don’t need counting if a group is small enough; subitizing will do the job, and it’s almost instant.

The brain has two methods for counting, and only one is officially called counting. That’s the regular way—when you look at a set of items and check them off, one by one. You have some system of remembering which have already been counted—you count from the top, perhaps—and then increment: 7, 8, 9...

The other way is faster, up to five times faster per item. It’s called subitizing. The catch: subitizing works for only really small numbers, up to about 4. But it’s fast! So fast that until recently it was believed to be instantaneous.

In Action

See how many stars there are in the two sets in Figure 3-3. You can tell how many are in set A just by looking (there are three), whereas it takes a little longer to see there are six in set B.

Figure 3-3. The set of stars on the left can be subitized; the one on the right cannot

I know this feels obvious, that it takes longer to see how many stars there are in the larger set. After it, there are more of them. But that’s exactly the point. If you can tell, and it feels like immediately, how many stars there are when there are three of them, why not when there are six? Why not when there are 100?

How It Works

Subitizing and counting do seem like different processes. If you look at studies of how long it takes ...