Confirmation bias is the cognitive tendency to search for, interpret, and favor information that supports one’s preexisting beliefs or opinions while dismissing or ignoring contradictory evidence. In The Age of Magical Overthinking, Montell explores how this bias affects everything from religious beliefs to conspiracy theories, showing how it reinforces deeply held convictions and leads to irrational behavior. Montell argues that confirmation bias is a universal human tendency, affecting everyone to some degree, whether in mundane decisions or significant political and social matters. While the bias can help people make quick, timely decisions by aligning their internal and external words, it often does so at the expense of critical thinking and objective reasoning. Montell also critiques how confirmation bias strengthens in-group relationships but fosters division and misinformation, especially in today’s polarized world.

Declinism is a cognitive bias that leads people to believe that society is in a continual state of decline, with the past perceived as better or more virtuous than the present. Montell discusses how this bias distorts modern perceptions, particularly in relation to nostalgia and doomsday thinking. Declinism is exacerbated by the fading bias effect, where negative memories fade faster than positive ones, leaving an overly idealized view of the past.