Why do humans fall in love, create art, make war? Quartz, director of the Social Cognitive Neuroscience Laboratory at Cal Tech, and Sejnowski, director of the Computational Neurobiology Laboratory at the Salk Institute, argue that these and other capabilities are the result of biology and culture working together. Challenging the view that human brains are hardwired for certain behaviors, they believe instead that "[y]our experience with the world literally helps build your brain."