Numerosity heuristic
Why people perceive greater quantity when items are divided into more units and how to apply numerosity heuristic in marketing.
In this issue
Hey 👋 The Crew here.
Before we wrote “can you believe next week is May already…” in this intro, we realized it’ll actually be—June.
Well, time flies when you’re having fun, right?
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You walk into a hotel bathroom and see a single, full-size bar of soap. Nice.
Now imagine you walk into the same bathroom again later. But this time, it’s stocked with three mini soaps.
Same purpose. Same basic utility. Same quantity even, but spread out to make three individual products.
Does it feel like you’re getting more? Chances are, yes, it does.
We can’t help ourselves. Even if we know the amount is equal, we can’t help but feel like a bigger number means a bigger quantity.
That’s the Numerosity heuristic.
In 1994, a group of psychologists introduced this concept after proving that their subjects see a resource as more substantial when it’s divided into a greater number of units.
For example, a pizza sliced into eight pieces tends to be perceived as bigger than the same pizza in six slices, even though they’re equal in size… and calories.
You can see this playing out across countless other real-life scenarios:
- 1000 loyalty points feels more rewarding than a $10 credit even if they’re worth the same.
- A bag with 30 mini candies seems bigger than one large bar of chocolate.
- “Get 10 templates” sounds more valuable than “1 master template.”
Now let’s see how you can take this heuristic and use it to become a selling machine.
Three ways to leverage Numerosity heuristic
Play the numerosity card for quick decisions
In the 1994 study we mentioned, experts asked participants to estimate the monetary value of eight arrays of randomly placed coins on a video monitor.
The coins had the same value, but were lined up differently to make it seem like there were more… or fewer.
But there was an additional catch.
Some participants were asked to provide their answers in two seconds.
The result? Participants under a time limit estimated the many-coin arrays had twice the value of the arrays with fewer coins.
In other words, when your customers are pressured to do something quickly, they’re likely to overvalue something if you include a bit of numerosity—or numbers.
Like this Disney email:
The image choice might be accidental or deliberate, but it proves our point. It’s not a big TV with a Disney+ logo. It’s a bunch of different content you can consume.
It’s the same subscription, same cost. Whether you’ll watch Andor or The Bear, or both. Or 100 shows. But you’ll value it more.
And given the time pressure, the deal sounds like a no-brainer.
The bigger, the better
What’s better than a product you need?
A product you need, shown in a much bigger size.
At least that’s what this 2016 report by Bagchi and Davis suggests. Apparently, people prefer larger objects because they feel more valuable.
So you should find ways to make your offer look bigger through visuals, layout, and language.
For example, you can enlarge the product on your landing page, show larger quantities of products in one image, or simply use heavier, thicker fonts in your ads for a more “hefty” presence.
… All of which helps to push your potential customer to buy.
Don’t believe us? Just look at the size of these cans:
Use precise numbers for added value
A recent study by Zhang and Schwarz found that consumers feel more confident in accuracy when estimates are expressed in more detail or higher granularity.
For example, saying your insurance policy lasts 730 days can feel more compelling than two years.
This is also why it is often better to state your delivery in days, not weeks. Promising 4–5 days is better than promising one week.
A good example: Instead of saying “Delivery in about a week,” Amazon often gives you highly specific windows, like: “Arrives Thursday, May 23, between 2–6 PM”
Precision makes your numbers feel earned.
As recently explained by one of its workers, Domino’s pizza does exactly this. As you make your order, you can track its preparation and time of arrival live, but the thing is… It’s not live at all.
It just guesses the time and the tracker moves by itself. As explained, it’s just there to “give you an illusion and make you feel more at ease.”
A date and a window of time feels more certain. And more valuable.
It also helps create feelings of anticipation and expectation. Not a bad side-effect, is it?
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ICYMI, last time we looked at the Barnum effect.
The “many-membered” Crew
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