Sometimes other people make choices we wouldn't.

They order vanilla ice cream. They quit a perfectly good job to go travel the world.

They vote for someone we really, really, really don't want to get elected. And if the decision-maker is a close friend or if the choice is one that affects you, you might wonder why they did it. You might even think you know why.

But the thing is, you're probably wrong about their motives more often than you think. [INTRO♪]. People can be good at understanding other people's thoughts and feelings—at times. The kind of everyday mind-reading you do when you make inside jokes with your best friends or infer that your partner is upset is called empathetic accuracy.

But people are much better at empathetic accuracy under certain circumstances, like in close relationships or when they're really motivated to understand someone. Generally speaking, though? Guessing what's going on in other people's heads is tricky.

That's in part because the same behavior can result from different motivations. For example, a 2016 study published in Science found that there were clear differences in brain activity when a person's generous behavior was motivated by empathy as opposed to the desire to pay someone else back. But… the end result was the exact same behavior—you couldn't tell the motivation by what the person did.

And since we aren't all walking around with brain scanners in our pockets, most of us have to do some inference-making and deductions when we're trying to figure out why people do what they do. And there's a whole bunch of biases that can lead us astray. Like the correspondence bias, which is our tendency to assume people's behaviors have to do with their beliefs and personality rather than the situation they're in.

Researchers demonstrated this in a now-classic 1967 study by having people give speeches about Fidel Castro, the communist revolutionary who was governing Cuba at the time. Subjects watched one of these pro- or anti-Castro speeches, and then they were asked to judge the speaker's feelings about Castro. Even when the participants knew the speaker had been assigned their position, they still believed they at least partially agreed with their speech.

We just tend to assume that people's behaviors represent who they are, not what's happening in their lives, even when we know the context for their decisions. And if the person is outside our cultural group, we do this even more—if we see their behavior as negative. If it's positive, then we suddenly think it's their situation or some external factor driving their good behavior.

That's a phenomenon known as the ultimate attribution error. Basically, we don't give people we consider “different” from us the benefit of the doubt. We also can't really cope with the idea that other people are complex and full of contradictions.

You know you're a multifaceted unicorn: sometimes you like to go out and party, and sometimes you just want to sit at home with your cat and binge SciShow episodes. But studies have found we tend to view others as more one-dimensional. In a 2016 study, for instance, participants viewing a fictional Facebook page for Joe Smith predicted that he'd prefer vacations similar to the one he just booked.

Like, if his page mentioned a vacation to a lake, participants rated him as more likely to go to the mountains in the future and much less likely to go to the city. Because nobody's ever enjoyed a lake and a city. Been camping lately?

Well, no cities for you, then! You don't like them! There are a whole bunch of other biases like this one that can affect how we interpret others' behavior.

The assumed similarity bias is our tendency to assume that people are fundamentally like us—even when they're not. If we might do something for a particular reason, we tend to think other people would do it for the same reason. Then there's the hostile attribution bias, which is our tendency to interpret other people's behavior as hostile or aggressive to us, even when it's just… not.

And according to what's known as the value-weight heuristic, we tend to consider a particular choice's most extreme traits as more influential in someone's decision than they actually are. This was demonstrated in a 2017 study where subjects were told that a woman named Julie had decided to move to Fort Lauderdale, Florida— a place that, apparently, the participants largely thought is delightful and sunny all the time. And the more delightful and sunny they thought it was, the bigger the role they thought the weather had played in Julie's decision to move there.

The same study also showed that people made interpersonal judgments based on these biased inferences and then used them to predict people's future choices—often incorrectly. But the studies did suggest a possible way to overcome some of this bias if you want to make more accurate assessments. They found that being asked to make the same decision before considering why someone else had made it made the subjects less likely to assume that other people's decisions were based on an extreme attribute.

In other words… walk a mile in their shoes. Which is something experts recommend across the board for trying to understand other people's motivations. It might seem a bit trite, but it works.

And if all else fails? There's always one sure-fire way to find out what someone's thinking:. Just ask them.

Thanks for watching this episode of SciShow Psych! If you really want to understand why people make the choices they do, you might also like our episode on how the company you keep can influence your opinions. [OUTRO♪].