Measures of conditioned emotional response

In experimental psychology the term conditioned emotional response refers to a phenomenon that is seen in classical conditioning after a conditioned stimulus (CS) has been paired with an emotion-producing unconditioned stimulus (US) such as electric shock. The conditioned emotional response is usually measured through its effect in suppressing an ongoing response. For example, a rat first learns to press a lever through operant conditioning. Classical conditioning follows: in a series of trials the rat is exposed to a CS, often a light or a noise. Each CS is followed by the US, an electric shock. As an association between the CS and US develops, the rat slows or stops its lever pressing when the CS comes on. The slower the rat presses, the stronger its conditioned emotional response, or "fear."