Study participants sat in a padded chair in the middle of an anechoic chamber, a room designed to dampen all sound and block out light. The researchers describe the setup as a “room within a room,” with thick outer walls and an inner chamber formed by metallic acoustic panels and a floating floor. In between the outer and inner walls are large fiberglass wedges. “This results in a very low-noise environment in which the sound pressure due to outside levels is below the threshold of hearing,” the researchers wrote.