The adhesive quality of peanut butter has just “registered” in my son’s brain. He never eats peanut butter and jelly without coating himself in peanut butter. But this time he is holding his arm straight out, having stuck the peanut-butter-side of his sandwich to his arm, and observing–with an incredulous smile–that it doesn’t fall off. He’s saying “Peanut Butter! Peanut Butter!” with great delight.