Should you trust your gut? It's complicated.

I often watch shows where decision making plays a key role, from police dramas to medical dramas and more. I've noticed a common theme: trust your gut. The oft-uttered phrase sounds cliché, but what truth is there to it? Should you trust your gut?

First, some vocab. When I say judgment, what I mean is the process of using the mind/senses as a measuring device, answering questions like "how hungry am I," "is this a good idea," or "do I like this person?" On the other hand, decision, I mean a choice between multiple concrete actions, like "will I eat mashed potatoes or pasta," "will I follow this plan or not," or "will I help this person or not?"

The chief of a fire brigade walks into a burning house. They can't quite put their finger on it, but something seems off. A sense of dread washes over them as they begin to shout "clear the house!" The firefighters in the house quickly flee from the building, and just in time; the building collapses only minutes later. The fire chief feels relief knowing that their call prevented a catastrophe, but they still don't know why they made that call to begin with.

The above story illustrates an instance where someone trusted their gut and prevented a catastrophe. But how did they know? First, let's start off with some basics. What that fire chief observed was called an intuitive judgment, often called a gut feeling. Like you read above, intuitive judgment happens both quickly and naturally–the fire chief did not consciously try to think about clearing the house. Both of these qualities were highly important in the decision the fire chief ultimately made. Had they stopped to think, they likely wouldn't have made a decision in time, assuming they even thought clearing the house was worthy of serious consideration.

Let's consider another classic example.

A bat and a ball cost $1.10 total. The bat costs exactly $1.00 more than the ball costs. How much does the ball cost?

If you're like most people (myself included), you likely experienced an intuitive judgment that the ball costs 10¢. This intuition is wrong. If the ball cost 10¢, then the bat must cost $1.10, making the total cost $1.20–not the $1.10 specified in the problem. The true answer is 5¢, such that the bat must cost $1.05, making the total $1.10. If you went with your gut on this one, you aren't alone. Many, many people have missed this problem. The difference between the people who get this problem right versus wrong is not that some people have better intuitions than others, it's that some people did not submit this intuition as their final answer. People who gave the correct answer experienced the same intuition but paused to check their answer, and in doing so found that their intuitive response needed to be adjusted. This is often true of intuitive judgment–it gets you only part of the way to the solution.

If you're like me, you probably want to do better than getting part of the way to solutions, especially for important decisions. Well, you're in luck, because your mind also comes equipped with the ability to more slowly and methodically consider problems. This is often called "trusting your head," and it tends to lead to improved decision making. Unfortunately, your mind will not always use this slower, more methodical approach. Why? Because thinking about every decision is a lot of work, and your mind actively tries to do as little work as possible. Daniel Kahneman summarized this dynamic in his book Thinking, Fast and Slow. He presents these two ways of thinking as two systems: system 1 (fast/intuitive) and system 2 (slow/methodical). The primary dynamic is that system 2, while often superior in performance, is lazy. So, if a situation doesn't merit the effort of system 2, system 1 quickly finds a solution with little effort.

Returning to the principle question, the answer is more complicated than it initially seems. While trusting your head (system 2) may be more reliable than trusting your gut, you will not be able to consistently rely on your head as a source of truth, whereas your gut is consistently available for solutions. Furthermore, in situations where there is a significant time constraint, deferring to slower thought processes may be impossible.

Up next: Why is intuition so fast?