Heuristics and biases in decision making, explained

Every day you make decisions and judgments. Sometimes you're able to think about them carefully, but other times you make them on the fly using little information. This is where heuristics come in.

Heuristics are straightforward rules of thumb that we develop based on our past experiences. They're cognitive tools that help us make quick decisions or judgments. Life would be exhausting if we had to deliberate over every one of the hundreds of choices we make every day.

So instead we use our heuristics as shortcuts to make judgements about the world around us. For example, rather than spending time deciding what to wear every day, you might have some default outfits. Or when faced with a lunch menu with too many options, you may opt for what you've enjoyed in the past.

Heuristics aren't about making the perfect decision or judgment, just about making one quickly. Heuristics play a role in our reasoning about the broader world too. As an example, consider the rate of violence in the world over the past century.

Is the world more or less violent in the past 20 years than previously? Heuristic reasoning might lead to think that the world is more violent today than it has been in the past. Every day we're confronted with images of tragedy in the news and on social media.

We might reasonably assume that the world is more violent today than ever before, using what's called an "availability heuristic. " That is, examples of violence that so readily available, we just naturally assume the world is more violent today. But in fact the world is more peaceful today than ever before in human history.

We may hear a lot about violent events but in terms of raw numbers, fewer people die today at the hands of other humans beings than ever before. So that heuristic about how violent the world is, is incorrect. In fact, a slew of other heuristics can easily to mistaken conclusions.

And it doesn't matter how smart or well educated you are. Anyone can place too much trust in the mental shortcuts they use to make sense of the world. Take this example.

Let's say a person tests positive for a rare disease, one that only one-in-a-thousand people have. What is the likelihood that he actually has the disease? Most of us would say the likelihood is very high based on the test results alone.

But what if the results were inaccurate 10% of the time? If the false positive rate is 10%, a common number in medical tests, then it is highly unlikely our patient has the disease. In fact, based on the prevalence of the disease and the test result, we can be 99% sure he doesn't have the disease.

This is because the odds of the getting a false positive result, one in 10, are much higher than the odds of actually having the disease, one in 1,000. But in multiple studies, physicians routinely get this wrong, overestimating the likelihood that their patient actually has the disease. Psychologists call this the "representativeness heuristic.

" People assume an individual case is more representative than it actually is. Our political views can especially suffer from an over-reliance on heuristics. Just consider how we deal with political issues.

We'll often let our political identities, and our heuristics about how right we think they are, stand in lieu of important details and information we need to have an informed viewpoint. Because our heuristics can so easily lead us to faulty conclusions, it's important to be humble about our views. In light our fallibility, we have to do something that doesn't come easy, we must recognize that the world is an uncertain place and that our judgements about it are often wrong.

We ought to listen to opinions we may initially consider wrong or even offensive. Our intuitions are useful, even necessary when it comes to making quick judgments about the world. But that doesn't mean they're correct.

Recognizing the flawed nature of your thinking is a bold first step to challenging it.