Conceptualized model of a human observer in a perceptual task measuring contrast threshold

Introduction There are several possible mechanisms that might underlie perceptual excellence, which we can describe by reference to a metaphor regarding audio amplifiers. There are several factors that limit a physical device such as a radio receiver. First, the internal amplifier has some intrinsic noise, which gets amplified along with the radio signal. Second, the radio tuner may be unacceptably wide, thus letting in unwanted noise from neighboring frequencies. Finally, the decision stage (in this case the human listener) may not be optimal. For instance, if the listener is not very familiar with the language coming in over the receiver, very little information will pass through the system.