More than a decade after Charles Darwin gave the world “The Origin of Species,” he published a lesser-known tome that connected the world of homo sapiens and lesser species inhabiting Planet Earth: “The Expression of Emotions in Man and Animals.” Therein, amid long discussions of sneering, blushing and smiling, Darwin tackled a gesture as well known to mobsters in Martin Scorsese movies as it is to parents of teenagers: the shrug. “As shrugging the shoulders generally implies ‘I cannot do this or that,’ so by a slight change, it sometimes implies ‘I won’t do it,'” Darwin wrote.