The authors have considerable experience with experimentally investigating instrumental behavior in humans, and more specifically the balance between goal- directed and habitual action control. They both developed tasks that are used by research groups around the world to investigate the neural basis thereof, as well as the clinical relevance. However, they have also for some time been aware of the limitations of these paradigms, in terms of revealing the specific contributions of the two underlying systems – habitual and goal-directed (as opposed to simply discussing ‘the balance’ between them). For this reason, they have independently tried to establish a paradigm with which to study a gradual shift from goal-directed to habitual control with overtraining. However, this translational step from animal to human research has proven a challenging one. When we found out that we had both been struggling to find evidence for over-trained habit independently, we decided to open the file drawer and publish our experiments together. We believe it is important to bring these findings to the attention of our colleagues, because based on this collection of studies, we believe that the relationship between overtraining and habits in humans has not been satisfactorily demonstrated in a manner akin to the original animal demonstrations. Our hope is that recognizing that it is nontrivial to instill habits in humans using this kind of procedure will inspire the development of new paradigms, theories and more critical investigation regarding this issue.