““Kagan hypothesized that infants born with an especially excitable amygdala would wiggle and howl when shown unfamiliar objects and grow up to be children who were more likely to feel vigilant whhen meeting new people. The four month olds who trhrashed their arms like punk rockers did so not because they were extroverts in the making, but because their little bodies reacted strongly--they were high-reactive to new sights, sounds and smells. The quiet infants were silent not because they were future introverts, just the opposite, but because they had nervous systems that were unmoved by novelty.””
