Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.13.092726v1?rss=1 Authors: Toth-Faber, E., Janacsek, K., Szollosi, A., Keri, S., Nemeth, D. Abstract: Acute stress can crucially influence learning and memory processes. A growing body of evidence shows that stress can induce a shift from cognitively demanding goal-directed to habitual, procedural forms of learning. However, the mechanisms underlying the shift are not yet understood. Here, we aimed to get an in-depth look into the effect of stress on the acquisition of procedural information with disentangling two aspects of procedural learning. We examined whether and how stress affects (1) processes and learning of probability-based information and (2) serial order-based information in the same experimental design, and (3) explicit access to the acquired information. Considering statistical learning, based on prior results, we primarily focused on the early phases of the task. We induced stress with the Socially Evaluated Cold Pressor Test in 27 young adults, while 26 participants were enrolled in the control group. Salivary cortisol levels and subjective ratings of affective states showed successful stress induction. After the stress induction, we measured procedural learning with the cued Alternating Serial Reaction Time task. We found that stress promoted the acquisition of probability-based information and did not alter the learning of order-based information. Post-block reports showed weaker explicit access to the order-based information in the stress group. Our results are in line with the theory of stress-induced memory shift and give a process-level understanding on how stress alters procedural learning. Copy rights belong to original authors. Visit the link for more info