Which law explains why a person in a quiet room is more startled by a knock at the door than a person in?

The phenomenon can be explained by the concept of sensory adaptation and the principles of signal detection theory. In a quiet room, a person's auditory system is more sensitive to sudden sounds due to the lack of background noise, making them more likely to perceive and react to the knock as a significant stimulus. Conversely, in a louder environment, the background noise can mask sudden sounds, leading to a diminished startle response.