Oh, I didn’t know it was a telephone number.
This from a teenager with whom we were playing a brain skills game. (Yes, it was a “bad choices” day for us.) My challenge had been to look at a string of 10 digits (7392541098) for 15 seconds and then repeat them: Not immediately, oh no, that would be too easy. I was to repeat them when my next turn came up, several minutes later.
To the surprise of the assembled masses, I rattled off the10 digits perfectly, but with slight pauses reflecting how I’d memorized them: 739 254 1098. So, no, it wasn’t a telephone number, although it sounded like one. Experience counts for something.
Remembering long strings of digits is hard, man. Never mind the savants who’ve trained to recite 80 digits of pi: Most of us can hold no more than 4 items in working memory at a time, unless we use some grouping trick as I did. More than that, I wonder if there’s a connection between the human brain and small numbers that goes beyond “what we can remember” to “how we think.”
I think of Adela Rogers St. John (1894 – 1988) using a three-pronged metaphor in one of her novels (reproduced roughly here from, ahem, memory):
Career, marriage, children:
No one can manage more than two charging horses.
I think of one of the best-known sayings about trade-offs:
Fast, cheap, good: Pick any two.
– Widely used in software development and consulting
I think about a friend’s daughter offering her wisdom:
You can have a special diet.
You can be a picky eater.
You can have someone else cook for you.
But you can’t have all three.
Some might see St. John’s view of a woman’s challenges as hopelessly dated: After all, her admittedly groundbreaking professional heyday was in the 1920s and 1930s. Some certainly see “Fast, cheap, good” as simplistic, even though it captures a truth, albeit not the whole truth, about project management. Some might even object to the limits of dietary accommodation. That’s OK. Just go eat at someone else’s house.
But I find it interesting that they’re all based around two and three. Indeed, where n is greater than three, I can’t think of a single saying built on this structure:
There are n+1 desirable outcomes
or factors or constraints:
Pick any n.
That is, there don’t seem to be any memorable “There are 4: Pick any 3” sayings, and I’m sure there aren’t any “There are 18: Pick any 17” sayings. No, we seem to think in onesies, twosies, and threesies. Getting more sophisticated than that requires a whiteboard, a trained facilitator, and a riveting exercise in pairwise comparisons.
So what? Well, it shows me how to simplify and expedite my own decision-making, especially when there are trade-offs to be made (And when are there not?): Limit the competing factors to three, and then pick any two.
I want you (I want you)
I need you (I need you)
But there ain’t no way I’m ever gonna love you
Now don’t be sad (Don’t be sad)
Cuz two outta three ain’t bad.