The extent to which a computer-synthesized continuum of major to minor triads was categorically perceived was examined using labeling and discrimination tests. The 32 listeners varied widely in " musicality," assessed by an objective test of basic musical skills. There was a strong positive relationship between musicality and ability to label the major/minor continuum consistently ( measured by the slope of the labeling function). Overall discrimination performance varied only weakly with musicality, although the pattern of discrimination performance across the continuum differed strongly among three listener subgroups, distinguished on the basis of musicality. The most "musical" listeners showed a close relationship between the position of the discrimination peak and the category boundary calculated from the labeling function, a strong indicator of categorical perception. On similar criteria, the evidence for categorical perception was nonexistent in the least musical listeners and moderate in an intermediate group. From the evidence that the extent of categorical perception appears to vary in a graded fashion with the degree of musicality, we conclude that categorical perception can arise primarily through a process of learning.