The effects of stress on memory depend on the specific memory process investigated and the temporal proximity between the stressful event and this memory process. While stress (indicated as red flash) long before encoding impairs memory formation, stress shortly before or after the presentation of new information generally enhances subsequent memory performance. In sharp contrast, stress before memory retrieval impairs the recall of information learned previously which may directly affect performance at exams. In education, knowledge needs to be frequently updated by new facts or concepts relating to prior knowledge. In addition to its effects on memory encoding and retrieval, stress appears to impair this integration of new information into existing knowledge structures.