Learning new things actually strengthens your brain — especially when you believe you can learn new things. It's a virtuous circle: When you think you're getting smarter, you study harder, making more nerve-cell connections, which in turn makes you ... smarter. This effect shows up consistently among experimental subjects, from seventh graders to college students to businesspeople. According to studies carried out by Stanford University psychology professor Carol Dweck and others, volunteers with a so-called growth mindset about learning ("persist in the face of setbacks") have more brain plasticity. In other words, their noggins are more adaptable. They exhibit increases in cognitive performance compared with those who have a so-called fixed mindset ("get defensive or give up easily"). "Many people believe they have a fixed level of intelligence, and that's that," Dweck says. "The cure is to change the mindset." Certain that we're wrong? Enjoy stupidity!