Before sliding into the racing simulator in a basement fabrication shop at the Massachusetts Institute of Technology, IMSA GTD Pro driver Max Esterson is asked to strap on some equipment. A chest harness will measure his heart rate, a headband will track his brain activity, and a wristband will detect electrodermal activity, which reflects the activation of sweat glands, a marker for emotional and physical stress responses. This story originally appeared in Volume 35 of Road & Track. Then, the 23-year-old is handed a necklace—specifically, a black plastic torc with tiny white tubes poking out from each side. “This is how we emit all the different scents,” says Awu Chen, a research assistant in the MIT Media Lab’s Tangible Media Group. Esterson clasps it around his neck, and the tubes rest at the base of his clavicles. The neckpiece is based on the Scentac X-Scent 3.0, a noncommercial prototype intended for wellness and scented-media applications. “We kind of hacked it,” Chen says. His team’s modifications provide the capacity for advanced customization and programming. Using staggered quantities, durations, and sequences, the tubes can produce thousands of scent combinations. Esterson looks suspicious. “I hope they’re all good smells?” he says, yawning. He’d landed in Boston early that morning. “The bathroom at the JetBlue terminal—you want to talk about smell?” Esterson continues. “That place might cause serious crashes.” Jokes aside, Esterson is here in Cambridge for an experiment. He is the lab rat. “Stress and driving are strongly correlated, and there’s a lot of research around that topic,” Chen says. “And there have been other studies that have measured the impact of scent on regular driving, for example, using mint to keep people awake.” The team here is measuring the physiological effects of various scents and what impact they might make on performance