Comparator hypothesis

The comparator hypothesis is a hypothesis in the field of the psychology of motivation and learning. Created by Ralph Miller, it established that responses are due to a comparison between the direct activation of the outcome and the indirect activation of the outcome.

The comparator hypothesis was the first model which successfully accounts for retrospective reevaluation phenomena. However, after the publication of the comparator hypothesis, traditional models like Wagner's SOP and the Rescorla-Wagner model were modified to be able to account for retrospective reevaluation phenomena.

Today, the comparator hypothesis can successfully account for counteraction phenomena, a topic in which both the traditional models and their reformulation tends to fail.