Tweens have power in the marketplace, and executives are listening. “Lyn Mikel Brown, a professor of education at Colby College who cowrote the 2006 Packaging Girlhood and the just-out Packaging Boyhood, said the very notion of tween — a marketing term, not a developmental stage, she notes — is ‘an erosion of any kind of boundary between childhood and adolescent. It’s marketing a very stereotypical, teen life.'”