social butterflies social network personality traits Outgoing vs. Shy shy children social network social network Life's Extremes: Outgoing vs. Shy personality traits extroversion/introversion shy children personality traits personality traits determined social network Life's Extremes: Outgoing vs. Shy personality traits extroverted social network even personality extroversion/introversion extroversion/introversion social butterflies Outgoing vs. Shy extroversion/introversion social network social network even personality personality traits beyond regular shyness extroversion/introversion personality traits social network