Humans may come into the world with a remarkably short list of hardwired fears—namely, loud noises and heights. Sandra Rosenberg unpacks this phenomenon and how the idea is supported by foundational research in behavioral psychology, including the famous 1960 “visual cliff” experiment by Eleanor J. Gibson and Richard D. Walk. In that study, infants were placed on a table with a glass surface extending over a drop-off pattern. Even without prior crawling experience, most babies instinctively avoided the apparent “cliff,” suggesting an inborn fear of falling or depth.