The German Research Foundation (DFG) has recently approved funding of the research unit "Extinction Learning: behavioral, neural, and clinical mechanisms", encompassing workgroups at the Universities of Bochum, Duisburg-Essen, and Marburg, for another three-year period. Extinction learning is a basic behavioral phenomenon in which an organism learns that two events which used to occur jointly have ceased doing so. Unlike acquisition, i.e. original learning, extinction is highly context-specific, which is one of the many indications that extinction is not just "unlearning" but constitutes a novel learning process distinct from original acquisition. Although extinction was first described more than 100 years ago by Russian physiologist Ivan Pavlov, many aspects of this phenomenon are still poorly understood. This is unfortunate, given that theories on the development and treatment of psychiatric disorders in part rely on extinction - e.g. psychotherapeutic interventions for phobias or psychological treatment of drug abuse. In the next three years, the research unit is expected to make significant contributions to our understanding of the neural and behavioral mechanisms of extinction learning. The scope of the projects within the unit ranges from basic research in animal models and humans to clinical applications in the treatment of phobias, enabling efficient transfer of insight gained from basic research to outpatients seeking treatment for anxiety disorders.