The purpose of generating artificial noise, whether intentional or not, may vary, depending on what is considered noise in a particular context. It can be used to experiment on a subject by controlling the frequency or amplitude of the artificial noise to ascertain how the subject interacts with external stimulation. For example, to test the sensitivity of a microphone noise-reducing filter, the test administrator could generate artificial noise in a laboratory setting to determine whether the microphone suppresses the noise (i.e. filters it out), or interprets the noise as something that is not noise (i.e. passes it through).