A tutorial review on methods for collecting similarity judgments from human observers

Similarity is a central concept in the study of cognition, having been identified as an explanatory factor in the dynamics of myriad psychological phenomena. The collection of similarity judgments, however, can be a difficult, laborious, and time-consuming process. There is presently a vast and diverse array of methodologies applied throughout the psychological sciences from which to gather judgments of similarity perceptions, and each carries its own relative advantages and disadvantages. Each method may be suitable for a specific set of contexts and stimuli but be inappropriate for others. This tutorial review is meant to serve as a guided tour of common similarity judgment-gathering methods currently utilized in the psychological sciences, and to provide an overview of how and when researchers should leverage them.