Duncko, R., Cornwell, B., Cui, L., Merikangas, K. R., &Grillon, C. (2007). Acute exposure to stress improves performance in trace eyeblink conditioning and spatial learning tasks in healthy men.

The present study investigated the effects of acute stress exposure on learning performance in humans using analogs of twoparadigms frequently used in animals. Healthy male participants were exposed to the cold pressor test (CPT) procedure, i.e.,insertion of the dominant hand into ice water for 60 sec. Following the CPT or the control procedure, participants completeda trace eyeblink conditioning task followed by a virtual navigation Morris water task (VNMWT). Hypothalamic-pituitary-adrenocortical(HPA) axis and sympathetic autonomic system (SAS) activity were assessed by measuring salivary cortisol, heart rate, and skinconductance at selected timepoints. Results revealed positive effects of stress on performance in both tasks. The stress groupshowed significantly more conditioned blinks than the control group during acquisition of trace eyeblink conditioning. Thestress group also performed significantly better in the VNMWT than the control group, with the former showing significantlyfewer failures to locate the hidden platform in the allotted time and smaller heading errors than the latter. Regression analysesrevealed positive relationships between HPA axis and SAS activity during stress and eyeblink conditioning performance. Ourresults directly extend findings from animal studies and suggest potential physiological mechanisms underlying stress andlearning.

Tsai, J. L., Knutson, B., & Fung, H. H. (2006). Cultural variation in affect valuation. Journal of personality and social psychology, 90(2), 288.

http://dx.doi.org/10.1037/0022-3514.90.2.288