Some quantitative properties of anxiety
Abstract"The magnitude of anxiety is measured by its effect upon . . . the rate with which hungry rats pressed a lever under periodic reinforcement with food. Repeated presentations of a tone terminated by an electric shock produced a state of anxiety in response to the tone . . . . When the shock was thus preceded by a period of anxiety it produced a much more extensive disturbance in behavior than an "unanticipated' shock . . . . During experimental extinction of the response to the lever the tone produced a decrease in the rate of responding, and the terminating shock was followed by a compensatory increase in rate which probably restored the original projected height of the extinction curve. The conditioned anxiety state was extinguished when the tone was presented for a prolonged period without the terminating shock. Spontaneous recovery from this extinction was nearly complete on the following day."