Standing up straight will make you look thinner, taller, and conveys an air of confidence to everyone you meet. And, as your mom always told you, it will keep you from developing a humpback in your older age. But in case you need another, less-appearance based reason to stop slouching already, a feature in the Wall Street Journal (that I read about on New York Mag) says that it might block you from thinking clearly. When you slouch, you put your body in a defensive position, which signals to your body to ramp up cortisol production and decrease testosterone. Both of these reactions can limit your problem solving ability and stunt your creative thinking. So follow your mom’s advice already, and stop slumping over your desk.