Psychology Facts

This is a list of interesting psychology facts. I'll add more regularly.

We are more likely to look for and believe information that confirms what we believe. This is the confirmation bias.1

If we hear an idea several times, we’re more likely to believe that it’s true. This is called the truth-by-repetition effect or the illusory truth effect. This can happen even when we know that an idea is false or ridiculous.2

We are more likely to believe that a conspiracy theory is true after we hear about it than before. This is partly because conspiracy theories are often more entertaining than factual explanations and they give rise to stronger emotions.3

Unwarranted beliefs are ideas or claims that are not supported by scientific evidence or are contradicted by it. There are 3 categories of unwarranted beliefs: pseudoscience, paranormal claims, and conspiracy theories. In general, people who believe one type of unwarranted beliefs are more likely to believe other types as well.4

Men and women are equally intelligent, but there are some differences between them when it comes to certain abilities. For example, men tend to be better at visual processing (generating and analyzing images) while women tend to better at processing speed (doing certain tasks quickly).5

IQ scores have been increasing for decades. This is called “The Flynn Effect”, named after the scientist who discovered this.6

Most people like to think that they are better than the average person when thinking about desirable traits like intelligence, 
attractiveness, driving skills, etc. This is called the better-than-average effect.7

Men tend to over-estimate their intelligence much more than women do. This called the male hubris, female humility effect.8


  1. ‘Confirmation Bias and the Persistence of Misinformation on Climate Change’, Y Zhou1 et al. (2021)
  2. ‘Is Earth a perfect square? Repetition increases the perceived truth of highly implausible statements’, Doris Lacassagne et al. (2022)
  3. ‘The entertainment value of conspiracy theories’, Jan-Willem van Prooijen et al. (2021)
  4. ‘The generality of belief in unsubstantiated claims’, D. Alan Bensley et al. (2020)
  5. ‘The sexes do not differ in general intelligence, but they do in some specifics’, Matthew R. Reynolds et al. (2022)
  6. ‘The Mean IQ of Americans: Massive Gains 1932 to 1978’, James R. Flynn (1984)
  7. ‘The Better-Than-Average Effect in Comparative Self-Evaluation: A Comprehensive Review and Meta-Analysis’, Ethan Zell et al. (2019)
  8. ‘Gender Differences in Self-Estimated Intelligence: Exploring the Male Hubris, Female Humility Problem’, David Reilly et al. (2022)