Learning and forgetting curves are not only integral issues for courses in introductory psychology, they are also of high practical relevance to students when it comes to the formation of realistic goals and expectations on learning outcomes. A paper-and-pencil-study investigated how well students of psychology (N = 82) have internalized the concepts of learning and forgetting curves. We developed a vignette-based assessment technique: drawing a hypothetical learning or forgetting curve in an empty coordinate system with time on the x-axis and performance on the y-axis, the starting point and endpoint being fixed. In spite of the free production format answers were quantified in a way that would allow for automated feedback in online teaching tools. For instance, learning which decelerates over time implies a curve above the diagonal while decelerated forgetting implies a curve below the diagonal. Deviating from this optimal solution, about 60% of the drawn learning and forgetting curves were classified as being close to the diagonal axis. Analyses on the individual level also documented poor consistency of knowledge. Students drawing a deceleration in learning were not more likely to also draw a deceleration in forgetting. Implications for future learning aids, for example, online feedback systems are discussed.