Irene Tracey is known as the Queen of Pain, and she calls her lab the “torture chamber.” She runs the Nuffield Department of Clinical Neurosciences at Oxford University. She studies how people’s brains react to pain. New Yorker writer Nicola Twilley offered to be Tracey’s test subject. Researchers stuck needles in Twiley’s calf, burned the back of her hand with a laser, and applied a cream to her shin, which contained capsaicin, the chemical responsible for the burning sensation in chili peppers. What does the research tell us, how might it be used, and is it ethical to hurt people for research?