Is It Cake? How Our Brain Deciphers Materials

Summary

One of the greatest questions of the modern age is: Is it cake? As in: Is it an espresso machine, or cake? Paint can, or cake? Air fryer, or …? Millions of viewers have watched rapt as TikTok bakers slice or bite into inedible-looking objects with fluffy, frosting-filled innards … or have tuned into Is It Cake?, the aptly named Netflix show. Why? As a form of entertainment, this kind of visual trick is hardly new. For centuries, artists have delighted in fooling us into thinking one material is another. From Michelangelo’s marble David, with his sinewy, soft-looking flesh, to Giovanni Strazza’s Veiled Virgin, draped in a marble veil that appears gossamer thin. What makes these illusions so mesmerizing? Maybe it’s because these classic works of art and these modern social media ruses test our ability to use an underappreciated skill that’s been essential to our species’ survival: identifying what stuff is made of. Over the past century, neuroscience has made great strides in understanding how the brain visually identifies objects—like mugs, trees, and faces. But the question of how we recognize what those objects are made of (smooth porcelain, rough bark, soft flesh) has been overlooked until relatively recently. “Our world contains both things and stuff, but things tend to get the attention,” wrote Edward H. Adelson, an MIT neuroscientist whose provocative 2001 paper, “On Seeing Stuff: The Perception of Materials by Humans and Machines,” spurred a flurry of material perception research.1“Yet materials are just as important as objects are,” he wrote. “Our world involves steel and glass, paper and plastic, food and drink, leather and lace, ice and snow, not to mention blood sweat and tears.”It’s strange that the field of material perception is so new, considering how essential the ability to decipher what things are made of is. “When we look around our world, everything is made of materials,” says Alexandra Schmid, a postdoc at the National Institutes of Health’s Nati...