Sure Santa Claus asks boys and girls what toys they want, but why they want them is a better question. The answer may have to do with a biological pre-wiring that influences boys’ and girls’ preferences based on the early roles of males and females. It’s commonly believed that boys and girls learn what types of toys they should like based solely on society’s expectations, but psychologist Gerianne Alexander’s work with vervet monkeys is challenging that notion. Alexander examined the monkeys as they interacted with toys. She and her collaborator, Melissa Hines of the University of London, found that the monkeys’ toy preferences were consistent along gender lines with those of human children. Though the monkeys had no concept of a “boy” toy and a “girl” toy, they still showed the same gender preferences in playing with the toys, Alexander says. That is, compared to female monkeys, male monkeys spent more time with “boy” toys, and the female monkeys, compared to their male counterparts, spent more time with “girl” toys.