Reducing the feature positive effect by alerting people to its existence.

The feature-positive effect (FPE) is the phenomenon that learning organisms are better at detecting the association between two present stimuli than between the absence of one stimulus and the presence of the other. Although the FPE was first described 40 years ago, it remains an ill-studied and ill-understood bias. The aim of the present study was to test whether the FPE can be remedied by simply alerting individuals to the possibility that the solution to a given problem may lie in the diagnosticity of a stimulus being absent. The results indicated that the instructions given to participants can indeed reduce the FPE.