But if they’re not anti-social, these kids are differently social. According to the psychologist Elaine Aron, author of the book Psychotherapy and the Highly Sensitive Person, 70% of children with a careful temperament grow up to be introverts, meaning they prefer minimally stimulating environments — a glass of wine with a close friend to a raucous party full of strangers. Some will grow up shy as well. Shyness and introversion are not the same thing. Shy people fear negative judgment, while introverts simply prefer less stimulation; shyness is inherently painful and introversion is not. But in a society that prizes the bold and the outspoken, both are perceived as disadvantages.

Yet we wouldn’t want to live in a world composed exclusively of bold extroverts. We desperately need people who pay what Aron calls “alert attention” to things. It’s no accident that introverts get better grades than extroverts, know more about most academic subjects and win a disproportionate number of Phi Beta Kappa keys and National Merit Scholarship finalist positions — even though their IQ scores are no higher. “The glory of the disposition that stops to consider stimuli rather than rushing to engage with them is its long association with intellectual and artistic achievement,” observes the science writer Winifred Gallagher. “Neither E=mc² nor Paradise Lost was dashed off by a party animal.”