The Rule of Five

Bart Leahy
Communications Consultant



Our CEO Jason Hundley has a curious theory. He explained it to me at a bar one night while his five fingers were wrapped around a glass of imperial pale ale: the best human thinking can be tied to the Rule of Five. What the heck does that mean? What on Earth is he talking about?

1. What on Earth is he talking about?

Jason believes that we humans generally remember things better if they’re given to us in numbers of five or less. It’s more or less hard-wired into us because of the way our hands are shaped.

Pick your situation: essays, speeches, presentations, designs, or even works of art: the clearest, best-thought-out products of the human mind have no more than five concepts to them. Even elaborate things like city plans or paintings by Leonardo da Vinci or Hieronymous Bosch, while they have multiple individual parts, are really only about a few concepts: in city plans where do people work, live, or play? In a painting depicting the afterlife, you’re looking at reward or punishment. The rest is just detail. If you go beyond five, Jason contends, thinking gets murky and the focus is lost.

2. What is he basing this ‘rule’ on?

For starters, there’s actually science behind this. For backup, Jason provided the following data points:

  • We have 5 senses: sight, hearing, touch, taste, and smell.
  • We have 5 extremities, for the most part: two legs, two arms, and one head.
  • We have 5 digits on each of our hands
  • We have 5 toes on each of our feet
  • Our zip codes have 5 digits (now 5 and 4)
  • Our phone numbers use a country code (1-3 numbers) – area code – (3) – prefix (3) and extension (4) four sections all less than 5 digits each.
  • Our SSN use a 3-2-4 (area number, group number, serial number format
  • We’re taught to write essays in five paragraphs.
  • Our personal names are less than 5 syllables. For people whose names are usually longer than 5 letters we tend to have ‘shortened’ names.
  • We use a 5-star rating for anything from restaurants to movies.
  • We have 5 Services in the largest military ever in the known world.
  • We have more than twenty ranks in the US Military and class them in less than 5 categories:
    • (Enlisted personnel E-1- E-3), Non-commissioned Officers (E-4 – E-6), and Senior NCOs (E-7-E-9) (Enlisted 9 ranks grouped in 3s)
    • Junior Officers (O1-O3), Officers (O-4-O-5), and Flag Officers (O6-O10)
  • There are also Warrant Officers (W-1 to W-4)

So we can base an organization comprising several hundred thousand people into three categories and no more than three groups per category with nor more than five ranks per category. And even the most stripes or stars an admiral or general can have in the U.S. Military are five.

Anything that’s really important, Jason says, can be boiled down to one to five essential thoughts. And so here I am, trying to explain the rest.

3. Is the Rule of Five too limiting?

This sort of base-ten numerology runs rampant through our culture, and probably for good reasons. Never mind the Twelve Apostles (3 X 4), the Four Furies, or the Four Elements (or Five, if you’re a science fiction fan).

The most we can remember at one time—whether it’s visual or auditory data, for example—is four to seven discrete pieces of information.[1] That appears to be a limitation of our senses, bandwidth, or both. We also have sensory limitations (six colors in the rainbow, with multiple variations, plus earth tones, black, and white. Our two eyes are at the front of our heads instead of on the side, our eyes only perceive light wavelengths between 390 and 750 nanometers, and the diminishing of our senses as we age.[2]

So what does it all mean?

Just this: if you want to make an impression and have people remember what you’ve said, you’re better off sharing five concepts or less. This turns out not to be a limitation, however; instead, it’s a good starting point for organizing your thoughts.

4. How does ZPFC use this theory?

Zero Point Frontiers’ engineering philosophy is to bring “clarity from complexity.” Jason’s Rule of Five fits very nicely into that philosophy, as it helps guide the engineering team into focusing on the basics: what do you want the widget to do? What’s really essential? Anything else is just detail.

We have a similar approach to company operations. Using this theory, ZPFC has plans to pursue no more than five disciplines in the long term: space, energy, nanotechnology, biotechnology, and robotics. When we develop lists of activities or ideas, we keep them chunked into no more than five or, at most, ten (2 X 5) when possible. The idea is to keep projects manageable and relatable in human terms. Add too many high-level requirements, and you end up with too much complexity…and believe me, we’ve supported projects where the number of “basic” (Level 1) requirements ran into the hundreds. At ZPFC, we believe that’s overthinking things a bit.

Our designs start from a minimum number of requirements and then details are added later. This minimum-function design approach means that additional features are only added as needed rather than starting with a long laundry list that is going to constrain the outcome and make it more costly before we even start.

5.  How can I use this theory?

The Rule of Five is actually a great time-saver, whether you’re starting a new project or just going on vacation. On a new project, you have have a whole list of features you want to incorporate, but you can probably bring down the list of necessities down to a literal handful: what will it do (1-3 items)? How will it work? What’s the benefit?

If you’re going on vacation, you might have ten things you want to do, but on a personal level, your needs might be simple: find activities we can do as a family, find good places to eat, find quiet places to relax.

The Rule of Five isn’t a scientific law or anything so grandiose. It is, however, a way of approaching your work—or your life—that lets you focus on what’s important. As an extra bonus, it can even help you organize your blogs. See what I did there?

[1] Ward, Matthew.  Worcester Polytechnic Institute:
[2] Gonzalez, Robert T. “10 Limits to Human Perception … and How They Shape Your World.” io9 July 7, 2012