The Implicit Association Test (IAT) requires responding to category contrasts such as young versus old, male versus female, and pleasant versus unpleasant. In introducing the IAT, A. G. Greenwald, D. E. McGhee, and J. L. K. Schwartz (1998) proposed that IAT measures reflect mental structures involving the nominal features of the IAT's categories (e.g., age, gender, or valence features). In contrast, K. Rothermund and D. Wentura proposed that IAT performance is dominated by salience asymmetries of the IAT's pairs of contrasted categories. To assess relative contributions of nominal feature contrasts versus salience asymmetries, the authors (a) briefly summarize the extensive evidence now available to support construct validity of the IAT as a measure based on nominal category features and (b) present 2 new experiments that yielded results problematic for the salience asymmetry interpretation.