What’s so special about a Skinner box?

An operant chamber (or ‘Skinner box’) is an apparatus used by psychologists to investigate animal learning, with a particular emphasis on schedules of reinforcement. Until a couple of days ago, I thought the benefits of the Skinner box paradigm were all fairly obvious: it reduces exposure to irrelevant stimuli, keeps the animal near the operandum (response lever or key), allows some behavioural freedom (the animal isn’t restrained) and enables the researcher to automatically control all important parameters within the experiment. However, good though these reasons are, it turns out that there is a more sophisticated theoretical rationale. Skinner (1969) explains this by contrasting operant chamber paradigms with the learning experiments conducted by Thorndike (1911). In one such experiment, a cat learns over successive trials to escape from a box by pressing a foot pedal linked to a door release mechanism. Thorndike describes the learning process as one where all responses that are not relevant to escaping from the box are gradually “stamped out” whilst all actions resulting in pressing the pedal are “stamped in” (p.36). Skinner explains that operant conditioning paradigms are a refined version of Thorndike’s experiments and that they allow for a more focused investigation of the relevant behaviour by stamping out irrelevant behaviours before the main part of the experiment begins:

By thoroughly adapting the rat to the box before the lever is made available, most of the competing behaviour can be “stamped out” before the response to be learned is ever emitted. Thorndike’s learning curve, showing the gradual disappearance of unsuccessful behaviour, then vanishes. In its place we are left with a conspicuous change in the successful response itself: an immediate, often quite abrupt, increase in rate (1969, pp.6-7).

References

Skinner, B. F. (1969). Contingencies of reinforcement. New Jersey: Prentice-Hall.

Thorndike, E. L. (1911). Animal intelligence: experimental studies. New York: The Macmillan Company.