Since the 1960s, developmental psychologists point to the “Visual Cliff”—an experiment that plops babies on a fake precipice—as proof that infants learn to fear heights as they learn to crawl. But over the past 25 years, Karen Adolph of NYU’s Infant Action Lab has shattered this myth through a series of rigorous (and adorable) experiments, revealing that while babies can learn from experiences near high ledges or narrow bridges, it’s not a phobia they acquire.