Recently, psychologists have emphasized the response process-that is, the psychological operations and behaviors that lead to test scores-when designing psychological tests, interpreting their results, and refining their validity. To illustrate the centrality of the response process in construct validity and test interpretation, we provide a historical, conceptual, and empirical review of the main uses of the background white space of the Rorschach cards, called space reversal (SR) and space integration (SI) in the Rorschach Performance Assessment System. We show how SR and SI's unique response processes result in different interpretations, and that reviewing their literatures with these distinct interpretations in mind produces the expected patterns of convergent and discriminant validity. That is, SR was uniquely related to measures of oppositionality; SI was uniquely related to measures of cognitive complexity; and both SR and SI were related to measures of creativity. Our review further suggests that the Comprehensive System use of a single space code for all uses of white space likely led to its lack of meta-analytic support as a measure of oppositionality (Mihura, Meyer, Dumitrascu, & Bombel, 2013 ). We close by discussing the use of the response process to improve test interpretation, develop better measures, and advance the design of research.