We use the term “Stockholm syndrome” to describe somebody who is held captive (metaphorically or literally) and shows sympathy with their captor. But despite the medical-sounding name, this has never been recognized as a mental health condition. It has no diagnostic criteria, and is a label more often applied by media than by psychologists.

The term “Stockholm syndrome” was originally coined for a woman, Kristin Enmark, who had been taken hostage, along with others, in a bank. She said during and after the situation that she trusted the captors not to hurt her and the other hostages, but that she was afraid the police would storm the building and get people killed. The hostage negotiator, who had never spoken to Enmark, told the media that Enmark’s critiques of the police response must have been because she had become emotionally or sexually attached to her captors.

The idea of a man getting a divorce, a sports car, and a new girlfriend when he hits 40 is a pop culture trope, but it’s not based in any inevitable “crisis” that one reaches at middle age.

Freudians speculated that at middle age, we start thinking about death and trying to rediscover our youth. But modern day psychologists say that, if anything, people tend to be happier and more stable in middle age—not to mention busy with family and work responsibilities.

When somebody buys a fancy car at that age, it’s more likely that they can finally afford the car they’ve always wanted—not that they’ve made a U-turn in their interests.

According to a 2012 TED talk, standing in a confident pose increases your testosterone, reduces your cortisol, and can change your life. If you’ve ever stood in a bathroom with your hands on your hips, visualizing confidence before walking into a job interview, then maybe this has helped—but probably not because of any special effects that posture has on your body.

That talk was based on a study that did seem to support that idea, but later studies were unable to replicate the effects on hormones. Whether the poses led to behavior changes, like being able to stick to a task longer, is unclear—studies have found mixed results. The researcher who delivered that TED talk has since written that she no longer studies or teaches power poses, saying “I do not think the effect is real.”

The idea of ranting angrily to a friend, or having a good cry while you wallow in your sadness, may sound like a good way to release your emotions. But while emotions can be expressed, they don’t really get “bottled up” if you don’t, or “released” when you finally talk about them.

Research on venting your anger has found that people get more angry, not less, when they write a rant or punch a sandbag while thinking about a person they’re mad at. What’s more, reading those rants also makes people feel more angry. So if you’re looking for a way to dissipate anger, try anger management tips like relaxation or journaling in a way that explores your feelings rather than just venting them.

If we only used 10% of our brains, what is the other 90% even there for? Not only is this trope inaccurate, it didn’t even come from an outdated study. It appears to have been made up by self-help writers in the 1920s, who were fond of claiming that most of us never develop our full mental potential (whatever that means).

Actual brain science has shown pretty clearly that every part of our brain is active (though maybe not every part at the same time), so it’s not like there’s a hidden treasure trove of neurons just waiting to be put to use. You might say metaphorically that we’re capable of more thoughts and skills than we currently have, but that’s just another way of saying humans can learn things—which you probably already knew.

It’s common knowledge in pop culture that a stressful life can give a person a stomach ulcer. While stress can arguably make us more susceptible to illness in general, ulcers were once thought to be related to repressed desires that we had been loved (and fed) more as children.

In reality, stomach ulcers are cause by bacteria (Helicobacter pylori) and can be cured with antibiotics. Famously, physician Barry Marshall drank a vial of the bacteria, gave himself an ulcer, cured the ulcer, and won a Nobel prize in medicine with his collaborator for the work.

Are you a visual learner who needs to see things? A kinesthetic learner who needs to act out or feel out a new idea? Sorry, but we don’t have inborn “learning types” that work so rigidly.

If these learning styles were real, you’d expect visual learners to do better when taught visually and worse when taught via auditory or kinesthetic lessons. But research continually shows that we can all learn from a variety of media, regardless of what type of learner we supposedly are.

Obsessive-compulsive disorder is real, but it doesn’t actually describe your interest in keeping your desk neat. It’s a mental health condition where you have intrusive, unwanted thoughts (obsessions), and engage in behaviors (compulsions) to deal with those thoughts. Sometimes the compulsions involve handwashing or arranging things in a specific order, but cleanliness isn’t OCD and OCD isn’t always associated with cleanliness. For example, many people with OCD engage in hoarding behavior and have cluttered homes.

Being “anal,” on the other hand, is not real, since it comes from Freud’s weird theories that hold that your current mental health depends on how you felt about poop as a baby.

There was once a trendy idea that your willpower is finite, and that you can use it up—deny yourself enough things, and by the end of the day you’ll be unable to resist anything tempting.

But this idea hasn’t panned out with further research. Some experiments find that people’s willpower can be depleted; others find no such effect. It’s more likely that willpower is a catchy name for “not doing stuff” rather than a solid psychological concept that lives in the brain.

Do crowds of people tend to turn violent? That’s a persistent myth, but there’s no reason to believe it’s actually true. Sure, there have been crowds that acted violently, as in riots or political rebellions; but there have also been plenty of crowds that protested nonviolently, or that protected their members from harm.

Reading the history of the “mob mentality” idea, it sure seems like people in power were choosing where to place the blame: not on a justifiable grievance by the people rebelling, but because they were driven to action by the very situation of being in a crowd. Hmm.

The idea that it takes 10,000 hours to master a subject—any subject—was popularized in the book Outliers. The data came from a study of violinists, and was bolstered with a few anecdotes about others (the Beatles spent a lot of time playing together, you see).

But there’s no such rule. Different subjects take different amounts of time to master, and mastery isn’t so easy to define anyway. And while people who are good at something tend to have spent a lot of time practicing, there’s no guarantee that practicing is the only thing you need to be great. Later studies, including another on violinists, found that practice is about as important as you’d expect—significant but hardly the only determining factor.

Grit, or the drive to persevere despite setbacks, is a favorite subject in the teaching world. It’s not that grit doesn’t exist—we can certainly describe this trait in others, or in ourselves. But there is a popular idea that grit is the most important thing, that it makes all the difference between underachievers and star students.

That’s a huge oversimplification, of course. For one thing, we have to ask ourselves what kind of obstacles we’re putting in students’ way that they need so much grit to overcome them. Educators have pointed out that it’s easier to say something is wrong with a student (not enough grit) than to fix the problems they are actually encountering.

And even when we look at grit in terms of personal traits, another educator observes that “most people do not persevere at things because they are good at persevering, they persevere because they find things that are worth investing in.”