Susan Cain does a wonderful job of balancing anecdotal explanations and scientific studies to go into great detail about what it means to be an introvert, why it's awesome, the pros and cons between introversion and extroversion, and how to best structure your life to function best as an introvert. For example, a developmental psychologist named Jerome Kagan did a long term study on a group of infants where they introduced the kids to a whole bunch of different stimuli and predicted which ones would be introverts and which would be extroverts. He predicted that the kids who pumped their arms and legs in response to the new things were introverts and the ones who sat there unresponsive were the extroverts. It turns out that introverts have amygdalas that react stronger to new and unknown situations. As a kid, the response to this is to react to it. As we grow older we tend to internalize those responses, but we feel much more aversion to new things then extroverts.
This explains why I've always been hesitant to try new foods, go new places by myself, interact with strangers, and so on. I can get over these things, but I have a built in wall of aversion that I have to punch through first. If I'm pressured to bust through this wall at a faster pace than I'm okay with, my reaction is to push back even stronger and refuse to do whatever it is. This might be a separate trait from introversion, since this particular response never came up in this book. I also am very opposed when someone tries to pressure someone else into doing something they don't want for a similar reason. This empathy is a trait of introversion, since we generally pick up on other peoples' emotions and also apparently feel guilty really easily (which explains why I apologize much more often than I probably should). But getting back to the book, if you think you're an introvert or know one and want to know how best to interact with them, I'd highly recommend this book.
