About the Book

We consider ourselves rational, modern people. Yet, we wear "lucky socks" to job interviews, avoid the number 13, and say "bless you" when someone sneezes. Anthropologist Sarah Jennings explores the persistence of irrational beliefs in "Knock on Wood."

Key Concepts

Jennings argues that superstition is not a sign of ignorance, but a psychological coping mechanism for uncertainty. When we lack control over an outcome (like in sports, gambling, or war), the brain creates rituals to impose order on chaos. The book draws on Skinner's pigeon experiments and modern neuroscience to explain "magical thinking" — the belief that our thoughts or actions can influence unrelated physical events.

Examples and Insights

From the rituals of NASA engineers to the curse of the Sports Illustrated cover, Jennings documents how these beliefs permeate high-stakes environments. She also examines the placebo effect of good luck charms, showing that believing in a lucky object can actually improve performance by reducing anxiety. A fascinating tour of the logical brain's illogical loopholes.