Perhaps it all started with the Ten Commandments. The list mongering persists more than 3,000 years later in the titling of popular articles about any subject, including employment and recruiting, e.g.,  “Top 10 Secrets of a Great Resume”, “7 Ways to Impress an HR manager” or “5 Reasons You Didn’t Get That Job”.

Whether you are a writer or a reader, finding out why such lists and specifically numbered lists, e.g., “The Top 5….”, are so appealing and effective should be very instructive, interesting and enlightening.

So, why do we love lists and why, in particular, five-item lists?

The Ten Commandments: Two Lists of Five

Ever since Moses’ two sets of five rules, we’ve paid special attention to lists. Lists of rules, lists of reasons, lists of types and categories, lists of admonitions and mistakes, lists of ingredients, lists of ways of doing things—the list of these lists is endless and unlimited, just like our fondness for lists that are shorter, rather than longer.

Again, perhaps because of the influence of the Bible, twelve in a list (e.g., “12 Steps”, Santa’s 12 reindeer, the 12 Days of Christmas and the names of the 12 jurors in jury trials) seems to be our preferred maximum (except in various other religious scriptures in which “the 84-fold path to enlightenment”, “the 92 virtues” or other such unwieldy lists get transmitted down the ages and through the catechisms of those religions’ faithful).

The Stunning Dominance of 5

The popularity of such numbered lists is truly staggering. Googling “5 ways to” in quotes, for more restricted and specific results, I got 89,400,000 results. That’s a lot, but then there are also all of the “five ways to” Google listings—that’s another 28,500,000 returns, for a total close to 120,000,000 and for just one digit: “5”., a.k.a. “five”.

Here’s how other numbers in the parade of “N ways to” (and “N reasons why”, in parentheses) fared in a Google search. Notice the prominent peaks at 5, 10 and 15—a pattern that is not only easily explained, but, as will be suggested below, explained in a way that accounts for the precise number of Mosaic commandments and the popularity of “5” and multiples of 5:

  • the 1/one way to: 84,350,000 (22,839,000)
  • 2/two ways to: 115,800,000 (13,940,000)
  • 3/three ways to: 73,400,000 (18,570,000)
  • 4/four ways to: 29,350,000 (7,480,000)
  • 5/five ways to: 117,900,000 (39,600,000) (note the spike here)
  • 6/six ways to: 24,340,000 (9,890,000) (note the plunge here)
  • 7/seven ways to: 35,370,000 (14,280,000)
  • 8/eight ways to: 33,600,000 (2,470,000)
  • 9/ways to: 11,050,000 (2,058,000)
  • 10/ten ways to: 125,000,000 (22,000,000) (note the spike here)
  • 11/eleven ways to: 5,841,000  (1,833,000) (note the plunge here)
  • 12/twelve ways to: 6,113,000 (1,355,000)
  • 13/thirteen ways to: 3,558,000 (5,150,000)
  • 14/fourteen ways to: 3,552,000 (368,800)
  • 15/fifteen ways to: 8,602,000 (1,286,000) (note the spike here)
  • 16/sixteen ways to: 1,450,000  (279,600) (note the plunge here)
  • 100/one hundred ways to: 18,866,000 (2,129,000) [inserted here for comparison with smaller digits].

Note that, in my investigations above, “5” is the champ, with a combined total of 162,900,000, just ahead of the Mosaic 10, which tallied 147,000,000. Both “5” and “10” handily whupped all the others, in addition to scoring more than three times the tally for “the main reason why” and ten times “the real reason why” (for which I must confess a fondness).

Why Lists?

So, why this fascination with numbered lists—and, in particular, why lists of five? Responding to the first, more general question, here are five (yes, five) reasons for the popularity of such lists:

1. Appearance of simplification: A list of “Ten Rules for Effective Management” seems to simplify the complex task of managing an enterprise. A list of cell-phone accessories simplifies ordering them. A list of Ten Commandments simplified the task of keeping desert tribes in line. Lists simplify sorting types and tasks.

2. Appearance of exhaustiveness and exclusiveness: If the items in the list do not actually exhaust and cover all of the types, categories, reasons, causes, etc., they can be made to appear to by identifying them as “the top” or “the main” ones. That makes our mental universe seem tidy. Exhaustively and, in addition, exclusively identifying listed factors, categories, etc., facilitates one-at-a-time, independent control of each.

An ideal list will always have these two characteristics—the set of items in it will be both “exhaustive”, i.e., complete, with no important items omitted, and “exclusive”, i.e., with no overlap or interdependence of the individual items.

For the purposes of control and management, the more exhaustive and exclusive the list, the better. A list of coin toss outcomes, e.g., “heads” or “tails” is such an exhaustive (no possibilities other than heads or tails) and exclusive (can’t be both heads and tails) classification and has both of these characteristics, which define what is called a “partition”.

Lists lacking one or both of these characteristics can still be useful, but will be much less so in connection with control or prediction, e.g., a partial or overlapping client list of  “top job requirements” (an example of overlapping listed requirements being “attention to detail”, “precision”, “accuracy”, “effective data organization”). This is a point further explored in #4, below.

3. Appearance of manageability of information: Short lists facilitate management of our memorization and memories of the items in them, of our presentation of the subject in a list format, and of their prioritization.

Best for this purpose are mnemonic lists, e.g., the “ABCD” rule the dermatologists use for recognizing you’ve got a potentially lethal melanoma on your back (“asymmetry”, “border that is irregular”, “color variation” and “diameter exceeding 6 millimeters”).

4. Appearance of control: A list item is frequently a control tool. From both a logical point of view and for the purpose of professional (self-) control, the following is a bad list of “The (Top) Five Ways to Impress Your Boss”: be well groomed, keep your shoes polished, make a good impression, study Latin and display personal pride. It is badly flawed because, clearly, if it is a list of “the (top) five ways”, it omits many other equally or more important factors, e.g., always be punctual, show initiative.

It also contains interdependent factors (being well groomed, displaying personal pride and having polished shoes), a problem that confuses the control issue through partial redundancies of effort. “Make a good impression” is useless as an item in a list of factors that will impress a boss, because it offers no guidance whatsoever as to how to control or do precisely that, and, worse, is presented as a subtype of itself, i.e., “make a good impression” as one way of making a good impression.

Finally, “study Latin” may impress a Vatican recruiter, but probably no other (prospective) boss and therefore will not consistently be a job-outcome control factor (potentially backfiring if you work at a Greek restaurant). A “top reason” should not apply for only a minority of the target audience.

5.  Appearance of comprehensibility: Lists make us feel that we understand and that we can communicate that understanding easily. Menus, which, after all, are merely lists, perfectly illustrate this feature of lists. All of the “N Ways to Do Y”, “N Reasons for Z” article titles that pop up in Google searches function the same way as the cover page of any restaurant menu, except that the former are designed to serve professional and personal objectives, rather than food.

But for the objective of comprehensibility, the lists can’t be too long. One reason I no longer pay attention to elementary particle physics is that the list of particles and their subtypes got too long (twelve types of elementary fermions. viz.,  six quarks and six leptons; six bosons, fourteen hypothetical fermions and bosons, and a plethora of hadrons, baryons and mesons—altogether, far too many to remember, much less understand.

Why 5?

As for the second question—why are lists of five items the most common?—the list of reasons for this, of course, also has five items.

The main overarching reason is that we are primates with pentadactyl extremities—five fingers on each hand and five toes on each foot, themselves branches off the pentagonal starfish-like overall symmetry of our bodies (one head, two arms, two legs—total five). So, counting based on 5 is natural, and as irresistible as “base 10” arithmetic, i.e., our 10-finger-based powers-of-ten calculation method, e.g., 10, 100, 1000.

Presumably, pigs, which are highly intelligent, would, in virtue of having tetradactyl appendages, i.e., 4 toes per foot, use base-8 math and follow “The Eight Commandments” (although in George Orwell’s pig-ruled “Animal Farm” the original list comprised exactly seven commandments).

With that main reason understood, the specific five reasons why human writers and readers like “5 Reasons Why” articles become obvious. These five reasons are that we have a(n):

  1. thumb
  2. index finger
  3. middle finger
  4. ring finger
  5. pinky finger

If you, despite the compelling evidence and cogent argumentation I’ve presented, are inclined to disagree with this 5-item analysis, allow me just one question.

What other explanation could you possibly consider giving a high-5?

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