An operant chamber, often called a Skinner box, is a controlled enclosure used to study operant conditioning. It allows precise measurement of an animal’s responses and of the consequences that follow them.

A typical chamber contains a lever or key that the animal can operate, a device for delivering food or water as reinforcement, and sometimes lights, tones, or other stimuli that signal when responses will be reinforced. Responses are automatically recorded, producing cumulative records that show the rate and pattern of behavior under different schedules of reinforcement. The environment is designed to minimize distractions so that the relationship between behavior and consequence is clear.

B.F. Skinner and his colleagues used the operant chamber to map the effects of continuous and intermittent reinforcement, extinction, discrimination, and punishment. The apparatus remains a standard tool in behavioral research and in the training of laboratory animals.

When the question is how consequences shape voluntary behavior, the operant chamber provides a clean experimental answer.