In his new book Suspicious Minds, psychologist and science writer Rob Brotherton makes the case that conspiracy theorists aren’t nuts — they’re us. Thanks to the way our brains work, it’s in our nature to see dots and connect them. It’s a product of evolution more than it is an emergent product of singular neuroses.

In the spirit of humanity’s shared paranoia, Brotherton walked Inverse through four popular conspiracies to get a sense of why we’re inclined to ignore Occam’s Razor, grow our beards out, and make hats out of tinfoil.

In your book, you compare the assassination of JFK — and the many theories about it — to the lack of theories regarding the failed assassination of Ronald Reagan. Your conclusion is that we like to see that big events have significant causes. Why is that?

The Kennedy assassination was one of the most momentous events of the 20th century. And it’s still one of the most widely believed conspiracy theories. There were polls conducted within a week of the assassination, and people were already disbelieving that Lee Harvey Oswald did it alone. Since then it remains popular — more than half of the people think that there was a conspiracy behind the assassination.

Compare that to failed assassinations, like the failed assassination of Reagan. Almost nobody thought there was a conspiracy, either at the time or since then. It’s a nice real-world example of something that has been shown in scientific research, which is that when the outcome of an event is bigger, we’re drawn to make proportionally big explanations for it. A conspiracy, in many ways, is the perfect big explanation, because it’s this grand thing that would involve, probably, many people. It would be culturally and socially significant if it were true.

We’re kind of doing it all the time in our own lives, when it’s trying to figure out why something big that happened to us like if we win the lottery or meet our life partner. For all these big life events, we’re tempted to search for big explanations, whether it’s fate or God’s design for us, whatever it might be. Whereas when little things happen that don’t have such big consequences, we don’t really think about that. We just chalk it up to random chaos. It doesn’t even cross our minds that there might be a bigger explanation for it.

If you take the JFK assassination and contrast that with the conspiracy theory that Obama’s birth certificate is a hoax, maybe that’s on the scale of a history-changing events, but it certainly isn’t as wide-reaching. Why might people be drawn to that type of conspiracy?

The birth certificate hoax is a good example of a conspiracy theory that’s very highly politicized. With the Kennedy assassination, people both on the left and the right of the political spectrum can believe it, though there are different variations. Whereas the Obama conspiracy theories are widely believed among Republican theorists, on the right of the political spectrum, and almost nobody on the left. It’s an example of how the beliefs we’re attracted to already resonate with what we believe in the world. For people who think that Democrats or liberals are trying to destroy society — that they’re bad, they’re evil — the conspiracy theories around Obama are going to resonate. For supporters of Obama, of course there’s no need to believe that. It appears implausible. This is confirmation bias, which we’re all kind of set up to find evidence to support a pre-existing belief, to find something more compelling and plausible than evidence that goes against that belief.

Anything that contradicts what we believe, we submit to more scrutiny, whereas anything that supports what we believe gets a free pass.

Do you think that the Obama birth certificate hoax and other politicized theories have the same sort of half-life that the JFK theory has — will we still be talking about it 50 years from now? Or do these things have a tendency to fade away?

That’s getting at the limit of research that’s been done so far. There really hasn’t been that much research looking into specific conspiracy theories and why they endure over time. I don’t really know, to be honest. One of the reasons for the popularity of the Kennedy conspiracy theories is it was such a big event and it’s still culturally significant. For Obama, the question of his birth certificate was a really big deal at the time when he was first running for office and then for reelection. But, you know, in 30 or 50 years maybe he’s not going to be that culturally relevant anymore so there’s a better chance of conspiracy theories fading away. But like I said we don’t really know.

Let’s take the example of climate change and global warming — is that a political bias, too?

It seems to be fairly politicized. People on the right of the political spectrum seem more likely to believe that climate change is a scientific hoax, that it’s designed to tamper with our political freedoms and freedom of industry. But again, there haven’t really been that much research into it, so we don’t really know why.

What other sort of biases pop up?

Another one of the biases that I’ve covered quite a lot is the intentionality bias.

It seems to be a pretty reliable finding that one of the reasons we entertain conspiracy theories is because we have this bias built into our minds. We just assume that any kind of ambiguous event has some purpose behind it. Somebody wanted it to happen or somebody made it happen.

[A good example] is the disappearance of MH-370, where it was this completely ambiguous event. There was almost no evidence, apart from what happened. It left a complete informational void, which we could fill in with our own kind of biases. Project what we want to believe onto it. So I think in that case the intentionality bias might have played a particularly important role. And rather than just assuming it was an accident or malfunction or something like that, we are drawn to assuming that somebody wanted it to happen.

Putting this in context of the big theme of your book, how do we get away from the idea that conspiracy theorists are crazy?

One of the questions we get asked the most often is whether there’s a link between having a mental illness and if you believe in conspiracy theories. It’s a product of this stereotype that we have of conspiracy theorists — usually paranoid loons lurking on the fringes of society, wearing tinfoil hats. I think it’s a complete misconception.

We’re all kind of conspiracy theorists and conspiracy theories resonate with us all. There’s been this theme amongst skeptics of conspiracy theories and people who debunk conspiracy theories: A lot of them paint believers in those kinds of terms, as being these weird people with these weird beliefs. They also paint in terms of black and white as well, which is one of the things I cover in the book.

Which is what conspiracy theories do, they paint the world in black and white, in terms of good versus evil. It’s an interesting parallel that people who debunk conspiracy theories, they argue that conspiracy theories are heralding an age of irrationality, putting the brakes on enlightenment and possibly bringing the world to a kind of apocalypse if everybody’s believing this stupid unfounded stuff. It’s a similarly black and white view of the world where they have these good, clever people who don’t buy into conspiracy theories and then you have this other group of stupid, irrational people that believe anything they’re told.

And I think both views of the world are equally mistaken. I think the world is much more gray than that.

Photos via Flickr.com/David Blackwell.