Author Susan Cain, a self-described introvert, accepted an invitation to do what she feared — give a TED talk. Although she was anxious on the big day, she got through it and wowed the audience.

As psychoanalyst Carl Jung, who introduced the concepts back in 1923 described, extroverts prefer to engage with the outer world of objects, sensory perception, and action. Introverts, on the other ...

You know that friend who seems quiet in groups but becomes a total chatterbox when you’re one-on-one? Or the person who’s always the life of the party but gets weirdly focused when they’re working ...