Modern life has not been easy on our brains. Average IQ scores rose steadily throughout the last century. Now they appear to be leveling off. The problem, according to neuroscientists, may be that we have reached our neurobiological limits. Our brains simply can’t work any harder. Luckily, science writer Annie Murphy Paul has a solution. In her bold new book, “The Extended Mind: The Power of Thinking Outside the Brain,” she draws on a wealth of scientific research to show that we’re smarter when we get out of our heads. By offloading our memories onto our phones, making decisions based on our bodily sensations, using tactile tools to solve abstract problems, drawing inspiration from our surroundings, and arguing with our friends, we can access intelligence that exists beyond the confines of our craniums. In this episode, Annie explains how to do it.

In 1958, a psychologist named Frank Rosenblatt took a five-ton computer, fed it a steady diet of punch cards, and taught it how to recognize the letter “A.” He called his creation the Perceptron, and his belief in its potential was like that of a deliriously proud parent. One day, he thought, the artificial intelligence he’d built would learn to recognize faces, speak like a human, translate languages, reproduce itself on an assembly line, and even fly to space — at which point, it would no longer be a computational marvel but a fully conscious being. The fact that you’ve never heard of the Perceptron tells you that none of Rosenblatt’s predictions came to pass — not in his lifetime, anyway. But a small band of brainy rebels never lost faith in the potential of AI to change the world. Thanks to their perseverance — along with dramatic improvements in computing power — they managed to make Rosenblatt’s prophecies a reality. The AI they built is what enables Facebook to recognize faces in the photos you upload. It’s the reason Siri and Alexa can (sometimes) understand what you’re saying, and Google can translate anything you write into 109 languages. Cade Metz has spent years chronicling the rise and rise of AI, first as a reporter at the New York Times and now in his new book, “Genius Makers.” In this forward-looking conversation, he tells Rufus what AI can do, where it’s headed, and whether we should be worried that supercomputers will wage war against humanity.