Just this week, 40 year old Matthew Coleman was charged with murder after he confessed to the FBI that he murdered his two children because he was convinced that they were going to "grow into monsters" after their mother passed down her "serpent DNA."

Matthew is a devout follower of the QAnon and "Lizard people" conspiracy theories and, although an extreme case, represents a fascinating phenomenon in the U.S. and around the world: wide-spread belief in conspiracy theories. Around 50% of U.S. adults believe in at least one conspiracy theory. Before researching this topic, I had assumed that this kind of thinking was increasing over time, but there is actually little evidence that conspiratorial thinking is growing.

Regardless, a reader asked me to look into why people believe in conspiracy theories, so here are three big ideas I got from the research literature on this topic.

1) The largest predictor of belief in a conspiracy theory is... belief in other conspiracy theories.

To study why people believe in conspiracy theories, a lot of studies do what is called a cross-sectional study: they survey a large group of people on which conspiracy theories they believe in, as well as other questions that might predict if they do, and correlate answers to people who believe in conspiracy theories and people who do not.

Perhaps not surprisingly, the correlation that appears in study after study is that belief in one conspiracy theory predicts belief in another. What this tells me is that belief in a conspiracy theory says a lot more about the person than the theory itself. To get a following, a conspiracy theory doesn't need to have real evidence, be logical, or even coherent. Some people are simply predisposed to believe in them, so what kind of character or environment causes belief in conspiracy theories?

2) Lack of self-esteem or a social safety net could cause conspiratorial thinking

Another theme I noticed in the literature was how researchers found that people who believed in conspiracy theories often had an inherent lack of self-esteem. Additionally, in their social life, they lacked stable safety nets like a good job, family structure, or community. One study I read found that fears about their employment was one of the largest predictors of conspiracy thinking.

People who are ostracized also tend to be vulnerable to conspiracy theories. One study even found that if people