Your Subitizing Superpower

Subitizing is a superpower we all possess, but it takes some practice to really be able to unlock all the potential.

I described it like this in It's the Thought That Counts:

If you glance quickly at a pile of identical items—let’s use bananas—you might be able to tell how many of them there are in an instant. It turns out that our brains are wired to identify very small numbers of things without taking the time to count them.

This is called subitizing, and most of us can do this with numbers up to four (although sometimes 3 is a more realistic cutoff). Our brains recognize patterns, so we don’t have to spend any mental energy to know whether there’s one, two, or three of something (and sometimes four). We simply know it.

This is all well and good in the world of quickly counting bananas, but the utility of subitizing goes way, way beyond its fundamental reach.

Now, in The Ample Sample, I talked all about how you often don’t need very much information in order to make an informed decision, like when Pierre-Simon Laplace estimated how deep the world’s oceans were, or when Eratosthenes estimated the circumference of the Earth. That’s all noteworthy, but that’s not what I’m here to talk about today.

Subitizing comes in really handy in a situation where you actually have a fair bit of raw data right in front of you, but it’s difficult to process in that moment—especially if there’s a ratio involved, like with three bananas out of a total of five. Three out of five is intuitively easy for our minds to understand—three bananas is an entire banana more than two.

But what about something like 30%?

If you have partners in a small business, it’s helpful to understand how much stake everyone has. A very easy way to give a rough estimate of what this means is to think of your 30% stake in the business as about a third. You own one third of that business, give or take, and operating that way nearly all the time is probably appropriate.

What about a partner who has, say, 10% in the business? Ten is too big to grasp in an instant like that—remember, we have a very hard time identifying piles larger than four things—so it’s much easier to think of the 10% partner as owning a third of what you own, which happens to be exactly right in this particular case.

The 10% partner doesn’t really own a third of a third of the business, as your quick story might imply, but it’s also not far off from reality. Functionally, this approach works incredibly well.

Why does this matter, really? What’s the use in taking an accurate ratio like an exact percentage, and then deliberately simplifying it in your mind’s eye?

Well, for one thing, it saves time. Sometimes you need to make a pretty quick decision about something, and having the ability to compare things quickly like this is very useful, even if it’s just a rough approximation. Sometimes, that’s exactly what you need to make a decision.

There’s also cognitive offloading, where we get to save that important (and very limited) mental energy to process the higher level thinking. Getting into the weeds with specific numbers requires an awful lot of the same resources your mind might use to contemplate a much deeper problem than a math ratio.

Instead, we can apply them to thinking about what to do with the information, or what to have for dinner, or we can use that mental energy to focus on our loved ones. Cognitive offloading helps you save your mental energy reserves for when you really need them.

Subitizing isn’t the only type of cognitive offloading, but it’s something we all know how to do. We can even apply some of the same concepts to more complex ratios we encounter in life, like statistics you hear in the news or a job offer at work involving a precent increase in salary. By quickly being able to grasp what’s truly at stake, you can get an awful lot more thinking done elsewhere.