George Polya is a famous mathematician who published a book in 1954 titled "Patterns of Plausible Inference".[i]In it, he examines which strategies we use to draw conclusions about things for which we have incomplete information. And that's most things, especially in relationships and communication. "Polya Patterns," as they are called, focus on how we come to find things credible and plausible. Polya points out that in most cases, we cannot know the truth about something because we don't have the time to gather enough information. So, we need a mental procedure to help us reliably weigh the plausibility of something presented to us.

The more severe the consequences are for you, or the more certain people/media are about something, the faster the process of belief formation will occur. It's as if the seed falls into fertile ground. For example, if you start experiencing some lower back pain, you might investigate if it's due to your office chair. But if the pain worsens and your colleagues also start complaining about the chairs, you quickly become convinced. Those chairs are no good, and something needs to be done about them. It becomes a strong belief influenced by the pain and the reactions of colleagues.

Growth Process

Polya describes several patterns through which beliefs can evolve from a possibility to a "hard truth." However, he does so in a rather mathematical manner. I'll extract the four simplest patterns and explain them in accessible language. Then, I'll add two more patterns that originate from social psychology:

1. The more often you notice a particular cause occurring in a situation, the more inclined you are to believe that cause is the instigator. It becomes increasingly plausible.
2. Even if you don't really see the cause, but the situation occurs repeatedly, you still get confirmed in your previous idea. That's actually strange; but in the absence of another cause, the belief still grows.
3. If there was another explanation, but it turns out to be incorrect, the credibility of your idea/possibility grows.
4. If the situation is comparable to a metaphor, then your suspicion becomes stronger. The logic of the metaphor is easily understood and makes us find the comparable cause more plausible.
5. The more people say it is so, the more plausible it becomes. Or if it is repeatedly described in the newspaper or mentioned in the news. Unconsciously, you often conform to what the majority says.
6. When you express your ideas to someone else, it's as if you're allowing the belief to take root. You hear yourself explaining why it's true, which also solidifies the belief.

[i] George Polya, 1954, ‘Patterns of Plausible Inference’