The critical test occurs after the original discrimination has been learned and its outcome changes. Successful performance requires the subject to stop relying on the previously reinforced choice, identify the new contingency, and adopt the alternative response. Comparing behavior before and after this change separates initial learning from flexibility in updating behavior.
Feedback signals that the former stimulus-outcome or response-outcome relationship is no longer valid. Subjects use this information to update expectations and guide acquisition of the alternative response. Performance therefore reflects not only whether behavior changes, but also how effectively the individual uses consequences to adjust decisions under altered contingencies.
Perseverative responding occurs when a subject continues selecting the previously rewarded option after reinforcement has shifted. This pattern indicates difficulty disengaging from an established response and adapting to new feedback. Measuring it helps researchers examine inhibitory control and distinguish persistent responding from more successful contingency updating.
A typical task begins with reinforcement-based training so the subject establishes a discrimination between alternatives. The experiment then changes which stimulus or response is rewarded, creating the reversal phase. Feedback during this phase supports learning of the new contingency, while researchers record behavior to evaluate adaptation and response change.
Researchers commonly assess errors, trials to criterion, and perseverative responding. Errors quantify incorrect choices, trials to criterion indicate how long acquisition of the changed contingency takes, and perseverative responding captures continued selection of the formerly rewarded option. Together, these measures describe the speed and quality of behavioral adaptation.
The paradigm provides a way to characterize adaptation when established relationships change, making it relevant to comparative behavioral research across species. It can also link flexibility with learning and decision-making, while studies of altered flexibility may help investigate relationships with neuropsychiatric function. The resulting measures support comparisons of adaptive behavior.