<p>Practices of data visualization in the social sciences are commonly understood to follow from substantive theoretical assumptions about social life. Yet the reverse relationship can be observed as well. The career of the Likert scale shows how a visual tool for data collection gradually morphed into a theory of the structure of the human mind. To capture this development, the social psychology of attitudes is best understood as a package-deal consisting of theory, method, and cases. Scholars buy into the package for different reasons. Initially, the package flourished because bipolar Likert scales facilitated the study of international conflict during World War II. War-time attitude researchers subsequently formulated a theory of the structure of attitudes as internalized bipolar scales. The Likert scale theory of the human mind has lost much of its appeal in recent decades. The conceptual apparatus to which it gave rise, however, stays in business because the visual characteristics of the scale offer practical advantages in the research process. At the present, many researchers continue to buy into what others consider an outdated theoretical conceptualization of attitudes because it offers all the advantage of a well-integrated package-deal. Theoretical alternatives to the Likert scale are shown to flourish only when they become part of a new package-deal.</p>