We all make stupid mistakes from time to time. History is replete with examples. Legend has it that the Trojans accepted the Greek’s “gift” of a huge wooden horse, which turned out to be hollow and filled with a crack team of Greek commandos. The Tower of Pisa started to lean even before construction was finished—and is not even the world’s farthest leaning tower. NASA taped over the original recordings of the moon landing, and operatives for Richard Nixon’s re-election committee were caught breaking into a Watergate office, setting in motion the greatest political scandal in U.S. history. More recently, the French government spent $15 billion on a fleet of new trains, only to discover that they were too wide for some 1,300 station platforms.

We readily recognize these incidents as stupid mistakes—epic blunders. On a more mundane level, we invest in get-rich-quick schemes, drive too fast, and make posts on social media that we later regret. But what, exactly, drives our perception of these actions as stupid mistakes, as opposed to bad luck? Their seeming mindlessness? The severity of the consequences? The responsibility of the people involved? Science can help us answer these questions.

In a study just published in the journal Intelligence, using search terms such as “stupid thing to do”, Balazs Aczel and his colleagues compiled a collection of stories describing stupid mistakes from sources such as The Huffington Post and TMZ. One story described a thief who broke into a house and stole a TV and later returned for the remote; another described burglars who intended to steal cell phones but instead stole GPS tracking devices that were turned on and gave police their exact location. The researchers then had a sample of university students rate each story on the responsibility of the people involved, the influence of the situation, the seriousness of the consequences, and other factors.

Analyses of the subjects’ ratings revealed three varieties of stupid mistakes. The first is when a person’s confidence outstrips their skill, as when a Pittsburgh man robbed two banks in broad daylight without wearing a disguise, believing that lemon juice he had rubbed on his face would make him invisible to security cameras. Or, in what is widely regarded as one of the top mascot failures in history, when Wild Wing of the Anaheim Ducks caught himself on fire attempting to leap over a burning wall (cheerleaders pulled him from the flames and he returned to action later in the game, unhurt). “This story of Duck a l'Orange County is no canard. A duck could get fired for this, or at least demoted to the Rotisserie League,” the New York Times reported.

The confidence-skill disconnect has been dubbed the Dunning-Kruger effect, after a study by social psychologists David Dunning and Justin Kruger. Dunning and Kruger had Cornell undergraduates perform tests of humor, logic, and grammar, and then rate how well they think they performed compared to other subjects in the study. The worst performing subjects, whose scores put them in the 12th percentile, estimated that they had performed in the 62nd percentile. Summarizing the findings, Dunning noted, “Poor performers—and we are all poor performers at some things—fail to see the flaws in their thinking or the answers they lack.” When we think we are at our best is sometimes when we are at our objective worst.

As any number of political scandals illustrate, the second type of stupid mistake involves impulsive acts—when our behavior seems out of control. In the scandal that became known as Weinergate, former U.S. representative Anthony Weiner sent lewd texts and pictures of himself to women he met on Facebook. (After resigning, Weiner continued his cyber-dalliances under the nom de plume Carlos Danger, and then fell prey to the Dunning-Kruger effect when he overestimated his support in the 2013 New York City mayoral primary; he received 5% of the vote.) More recently, in Michigan, state representative Todd Courser, a Tea Party conservative, admitted to sending an anonymous email to Republican Party operatives and members of the media falsely claiming that he had been caught having sex with a male prostitute, with the aim of making expected revelations that he had an affair with fellow representative Cindy Gamrat seem like part of a smear campaign. In an audio recording of a conversation secretly made by a staff member, Courser described his self-smear strategy as a “controlled burn of me” designed to “inoculate the herd” against the as-yet-unmade allegations.

The final variety of stupid mistake involves lapses of attention—Homer Simpsonesque D’oh moments. As arguably the best example from American sports history, in the 1929 Rose Bowl, University of California star Roy Riegels recovered a fumble and returned it 65 yards the wrong way. Riegel’s blunder set up a safety for Georgia Tech, which turned out to be the deciding factor in the game. Minnesota Viking Jim Marshall, a two-time pro-bowler and team captain, duplicated the feat in a 1964 game against the San Francisco 49ers, prompting Vikings coach Norm Van Brocklin to remark after the game, “Jim, you did the most interesting thing in this game today.” Aczel and colleagues’ analyses revealed that subjects viewed this category of stupid mistake as the least stupid.

It is, of course, unrealistic to think that we could ever eliminate human error. To err will always be human. However, this research gives us a better description of our failings and foibles, and a place to start in thinking about interventions and prescriptions to help us err less. This research also reminds us of our shared human frailties. We are all prone to overestimating our abilities, to making impulsive decisions, and to lapses of attention. This simple realization makes stupid mistakes seem, perhaps, a little less stupid — and a little more human.