For many parents, having a child who seems unusually introverted is a relief. There’s little need to worry about him sneaking off to parties, staying out past his curfew socializing, or getting into many other common forms of mischief. A quiet child is, according to conventional wisdom, a “good” child. If you’re the parent of a gifted kid, however, it’s worthwhile to take a second look at your child’s low-key social life. Not all bright children naturally wish to…