We all know people who overthink seemingly simple decisions. Who stack up the sandwich counter line while they decide between banana or cherry peppers. Who make the fulfillment department twiddle its collective thumbs while they decide whether to expedite the shipping on a late order.

Who, as Jeff Bezos would say, assume most two-way door decisions (easily reversible) are one-way door decisions (almost impossible to reverse), and wind up making few decisions at all.

Chances are, you also consider yourself an overthinker: While writing Soundtracks: The Surprising Solution to Overthinking, over 99 percent of the 10,000 people author Jon Acuff surveyed said they often overthink.

But are you?

Research shows most of us spend surprisingly little time making major decisions. Take personal finance: More than half of us spend as much or more time planning for a vacation than planning our financial futures. Or buying a car: Nearly half of us visit just one dealership when buying a car, and 1 in 6 skip a test drive. Or buying a home: The average home buyer visits just four properties before making a purchase decision.

Maybe that's you. Maybe it's not. So let's play a simple game. Imagine there are two jars. One contains mostly yellow balls with a few green ones mixed in. The other contains mostly green balls with a few yellows mixed in. I give you one jar and tell you to take out one ball at a time. Your job is to stop when you think you know whether the jar you have is a green ball jar or a yellow ball jar.

Here goes:

  • The first ball you pull out is green. 
  • The next ball is yellow.
  • The next ball is green.
  • The next ball is green.
  • The next ball is yellow.

When did you stop? If you stopped after the first ball, you definitely tend not to overthink. If you stopped after the second, you're a little less likely to jump to quick conclusions. (If you still haven't stopped, you tend to like a lot of data before reaching a conclusion.)

While it's a silly game, there is this: Researchers who conducted a version of that game determined that the less "data" a player needed to see, the more errors they were likely to make in decision making and reasoning. They jumped to quick -- and incorrect -- conclusions on brainteasers. They were more likely to be tempted into making inferior bets in gambling tasks.

They also tended to be overconfident -- even when they turned out to be wrong -- in the accuracy of their knowledge. (Think Dunning-Kruger Effect.)

The differences in decision quality between those who jumped and those who did not remained even after we took intelligence, measured by a test of verbal intellect, and personality differences into account. Our data also suggested the difference was not merely because jumpers rushed through our tasks.

What was the difference? People who tend to jump to conclusions tend not to engage in what psychologists call Type 2 reasoning: formulating plans, beliefs and actions through calculated methodical thinking.

We all engage in Type 1 reasoning, the automated thinking process that uses context and previous experience to assimilate newly acquired stimuli into pre-existing knowledge structures. (Or in non-researcher-speak, using experience and pattern-matching to make quick decisions, like seeing a car headed your way and automatically waiting to cross the street.)

The Type 1 folks were more likely to decide the jar contained green balls simply because the odds were much greater that the first ball they took would be the dominant color. Statistics were on their side.

People less likely to jump to conclusions engage in Type 1 reasoning, since none of us can help it. But they were emotionally intelligent enough to understand that tendency and mix in some Type 2 reasoning as well.

"The first ball is green?" they might have thought. "Odds are, that means most of the balls are green. But still, what if I happened to pull out one of the only yellow ones? Better take another ball to be sure. Hmm. Yellow ball. Have to take another one. Green. Seems like this is a green jar...but I still don't have enough data to be sure. Better take one more...." 

So how can you avoid jumping to conclusions -- without becoming an overthinker in the process?

One way is to embrace the Jeff Bezos 70 Percent Rule. Here's Bezos:

Many decisions are reversible, two-way doors. Those decisions can use a light-weight process. Most decisions should probably be made with somewhere around 70 percent of the information you wish you had.

Some decisions are consequential and irreversible or nearly irreversible -- one-way doors -- and these decisions must be made methodically, carefully, slowly, with great deliberation and consultation. If you walk through and don't like what you see on the other side, you can't get back to where you were before.

But most decisions aren't like that -- they are changeable, reversible -- they're two-way doors. If you've made a suboptimal two-way door decision, you don't have to live with the consequences for that long. You can reopen the door and go back through. 

The next time you struggle to make a decision, first determine the consequences.

What you have for lunch? Really doesn't matter. Whether you expedite shipping? Matters, but the cost-benefit consequences are easy to calculate.

In either case, overthinking is a waste of time.

Whether you should fire an under-performing employee? The consequences are huge, for your business and the employee. 

And if you do decide to fire him, there's no going back.

Which makes it a decision you really can't overthink.