Aesthetic sensitivity is a core idea in empirical aesthetics, which refers to the study of the causes of individual variation in aesthetic appreciation. Throughout the history of the discipline, however, aesthetic sensitivity has been conceived of in several different ways. In this chapter, I survey the three most prominent theories of aesthetic sensitivity. First, I review literature promoting a normative notion and determinist view of aesthetic sensitivity, especially associated with the work of Cyril Burt and Hans Eysenck. Then I review arguments for a normative and educative view—primarily defended by Irving Child. Finally, I discuss a more recent theory of aesthetic sensitivity that conceives of aesthetic sensitivity as the individual’s responsiveness to a stimulus feature. Together, these overviews will provide the reader a first introduction to the main accounts of why people vary so profoundly in what they like and dislike.