It seems that every family has an Uncle Joe—the guy who goes on and on about conspiracy theories at the holiday dinner table. The 9/11 attack was orchestrated by the government. The moon landing was filmed in Hollywood. Oswald did not act alone in the Kennedy assassination. And don’t get me started on . Record low temperatures this Christmas, and you expect me to believe the world is actually getting warmer? Give me a break.

Maybe we should give Uncle Joe a break, or at least try to understand where he’s coming from. Why do some people believe in conspiracy theories anyway? This is exactly the question posed by British psychologist Karen Douglas and her colleagues in a recent article in the journal Current Directions in Psychological Science.

The researchers found that reasons for believing in conspiracy theories can be grouped into three categories:

The desire for understanding and certainty

The desire for control and security

The desire to maintain a positive

Let’s look at each of these motives in turn.

The desire for understanding and certainty. Seeking explanations for events is a natural human desire. We’re constantly asking why things happen the way they do. Why does it have to rain the day I want to go out? Why did she give me the cold shoulder like that? Why can’t you understand what I’m trying to tell you?

And we don’t just ask questions. We also quickly find answers to those questions—not necessarily the true answers, but rather answers that comfort us or that fit into our worldview. It’s raining because I always have the worst luck. She gave me the cold shoulder because she can’t stand it when she doesn’t get her way. You can’t understand what I’m saying because you’re just not listening.

We all harbor false beliefs, that is, things we believe to be true but in fact are not. For example, if you believe Sydney is the capital of Australia, you’re the victim of a false belief. But once you’re confronted with the fact Canberra is the capital of Australia, you’ll readily change your mind. After all, you were simply misinformed, and you’re not emotionally invested in it.

Conspiracy theories are also false beliefs, by definition. But people who believe in them have a vested interest in maintaining them. First, they’ve put some effort into understanding the conspiracy-theory explanation for the event, whether by reading books, going to web sites, or watching TV programs that support their beliefs. Uncertainty is an unpleasant state, and conspiracy theories provide a sense of understanding and certainty that is comforting.

The desire for control and security. People need to feel they’re in control of their lives. For instance, many people feel safer when they’re the driver in the car rather than a passenger. Of course, even the best drivers can get into accidents for reasons beyond their control.

Likewise, conspiracy theories can give their believers a sense of control and security. This is especially true when the alternative account feels threatening. For example, if global temperatures are rising catastrophically due to human activity, then I’ll have to make painful changes to my comfortable lifestyle. But if pundits and politicians assure me that global warming is a hoax, then I can maintain my current way of living. This kind of is an important component in conspiracy theory beliefs.

The desire to maintain a positive self-image. Research shows that people who feel socially marginalized are more likely to believe in conspiracy theories. We all have a desire to maintain a positive self-image, which usually comes from the roles we play in life—our jobs and our relationships with family and friends. When we know we make a positive difference in the lives of others—as parent, spouse, friend, teacher or mentor—we see our own lives as worthwhile, and we feel good about ourselves.

But say Uncle Joe is on disability and hasn’t worked in years. He feels socially excluded. However, he does have plenty of time to surf the internet for information about conspiracy theories, and he can chat online with others who hold similar beliefs. Thus, belief in conspiracy theories gives Uncle Joe a sense of community.

Furthermore, his research into conspiracy theories has given him a sense that he is the holder of privileged knowledge. Most people who believe global warming is real or that vaccines are safe don’t do so because they understand the science. Rather, they trust the experts. And so, when Uncle Joe starts trotting out all the “evidence” against global warming, it can be difficult to make a reasonable counterargument. All you’ve got is the feeling that the conspiracy theory seems too complicated to be true, but from Uncle Joe’s perspective, it’s clear he knows more about the subject than you do.

In sum, we have a good understanding of what motivates people to believe in conspiracy theories. That is, they do so because of three basic needs we all have: to understand the world around us, to feel secure and in control, and to maintain a positive self-image. But do conspiracy-theory beliefs actually help people satisfy these needs?

Studies have found that when college students are exposed to conspiracy theories, they show an increased sense of insecurity. This has led some researchers to conclude that conspiracy-theory belief is self-defeating. However, as Douglas and her colleagues point out, most college students have little to believe in conspiracy theories in the first place. What’s really needed, they argue, are some carefully designed studies that directly examine those who already believe in conspiracy theories.

Regardless of the outcome of these future studies, the real question for us now is how to deal with the Uncle Joe in our life. You may offer counterevidence in an attempt convince him to give up his conspiracy theories, but you’re unlikely to succeed. This is because you’re arguing facts, while Uncle Joe is defending his sense of security and his positive feelings about himself. And for all of us, self-image trumps facts every time.

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