Moderate stress enhances immediate and delayed retrieval of educationally relevant material in healthy young men.

Retrieval practice is a powerful memory enhancer. However, in educational settings, test taking is often experienced as a stressful event. While it is known that stress can impair retrieval processes, little is known about the delayed consequences of testing memory for educationally relevant material under stressful conditions, which is the focus of the present study. Participants (38 women, 37 men) memorized a scientific text passage on Day 1. On Day 2, they were either exposed to a stressor (cold pressor test; CPS) or a warm water control, and immediately afterward, they were asked to recall the text passage (i.e., retrieval under stress vs. control). Salivary cortisol was measured as an index of the stress response before, and 20 min after the CPS versus control treatment. The delayed effects of testing under stress were assessed with a final recall test on Day 3. In comparison to the control condition, CPS caused significant increases in salivary cortisol, and, surprisingly resulted in enhanced memory in men. Importantly, this enhancement was not only observed in the test that immediately followed the stressor, but also in the delayed test. In women, CPS caused only marginal increases in cortisol concentrations, and retrieval remained unaffected. Our study suggests that moderate stress can improve memory performance for educationally relevant material in a long-lasting manner in healthy young men.