The main idea is that, while growing up, a person often has powerful and emotional experiences that inform their worldview and personality development.
According to the Heath brothers (and all the research they cite in their book), most of these “paradigm shifting” experiences happen during a person’s teens, 20’s, and begin tapering off during a person’s 30’s. They become almost non-existent for people over 40. And thus, people become frozen at a certain stage of their personality — and assume that’s how it’s supposed to be.
However, the Heath brothers explain that this doesn’t need to be the case. You can actually manufacture these experiences regularly, and throughout your entire life.
The reason most people stop having “peak experiences” — which according to Dr. Abraham Maslow, is required to become fully actualized as a person — is because they settle into societal norms.
They stop growing.
They stop putting themselves into wildly new and demanding situations. They stop exercising faith after having life experiences — and grow to become skeptical or cynical.