The prototype of indicators of a relationship partner who can be trusted to be responsive at times of stress is one kind of social knowledge structure. The Knowledge of Indicators (KNOWI) Task assesses individual differences in knowledge about these prototypic indicators. In constructing the KNOWI, an iterative procedure was used in an attempt to identify those indicators for which ratings of prototypicality are not influenced by social desirability. Study 1 demonstrated that the correlation between ratings of prototypicality and social desirability is indeed eliminated for the final set of indicators retained in the KNOWI. Study 2 tested the prototype matching hypothesis: Comparing an actual partner to the prototype might shape global judgments about that partner's responsiveness. Because in Study 2 only those indicators that are uncorrelated with social desirability were used, this result cannot be explained by social desirability. These results support the construct validity of the indicators used in the KNOWI Task, which seems to be a precise assessment tool not influenced by social desirability.