In discussing the origins of the Extrovert Ideal, Cain refers to the work of historian Warren Susman. In his book Culture as History, Susman argues that early America was a Culture of Character. Lasting through the 19th century, this social ideal emphasized the values of hard work, honesty, and honor. It was not outward-facing—for the benefit of others—but inward-facing and private. What you did when you were alone mattered more than what you did in public.

Contrasting with the Culture of Character, the Culture of Personality took hold in America beginning in the early 20th century. In Culture as History, Susman explains that this arose in tandem with mass migration to urban areas, when first impressions became more important because the people one came into contact with were strangers. The rise of the Culture of Personality also coincided with the rise of business—when selling became a constant in society, people were encouraged to be “bold and entertaining” (21). This soon became what Cain calls the Extrovert Ideal in American society, which exists to this day.

In refuting the notion that collaboration always yields the best ideas—part of the Extrovert Ideal—Cain refers to what one researcher called “the key to exceptional achievement” (81).