Working Memory Performance Under Stress.

Acute stress and chronic stress change the physiology and function of the individual. As one facet, stress and its neuroendocrine correlates - with glucocorticoids in particular - modulate memory in a concerted action. With respect to working memory, impairing effects of acute stress and increased levels of glucocorticoids could be expected, but empirical evidence on moderating effects of cortisol on working memory is ambiguous in human studies. In the current study, we thus aimed to investigate cortisol stress responses and memory performance. Older men and women (32 men, 43 women, aged 61-67 years) underwent the Trier Social Stress Test (TSST) and performed the 2-back task before and after exposure to acute stress. In line with theoretical assumptions, we found that higher cortisol stress responses led to a decline of working memory performance in men. However, the opposite was evident for women, who appeared to benefit from higher stress responses. This effect was evident for accuracy, but not for reaction time. In conclusion, cortisol might mediate working memory alterations with stress in a sex-specific manner in older people. Possible mechanisms and causes for these sex differences put a focus on endocrine changes in the aging population that might lead to differential effects across the lifespan.

The Opposite of Stress.

Cognition is affected by psychophysiological states. While the influence of stress on cognition has been investigated intensively, less studies have addressed how the opposite of stress, a state of relaxation, affects cognition. We investigated whether the extent of parasympathetic activation is positively related to divergent thinking. Sixty healthy female participants were randomly allocated to a standardized vagus nerve massage (n = 19), a standardized soft shoulder massage (n = 22), or a resting control group (n = 19). Subsequently, participants completed the Alternative Uses Test (AUT), a measure of divergent thinking. Respiratory sinus arrhythmia (RSA), a vagally mediated heart rate variability component, was monitored throughout the experiment. The area under the curve with respect to the increase was calculated for RSA trajectories as an indicator of vagal tone during the relaxing intervention. Regressions tested the effect of vagal tone on AUT outcomes. We found an association between vagal tone and subsequent AUT outcomes. Yet, this association was no longer significant when controlling for the effect of the creative potential of an individual, which was strongly related to AUT outcomes. Being exploratory, we found a positive association between creative potential and vagal tone. These results imply that creative potential might be related to the capacity to relax.