Left – analytical, right – creative: that is a misconception many people still have about the two of the halves of brain. Although this is exaggerated, both hemispheres display differences in task processing – so called functional hemispheric asymmetries (FHAs). These FHAs have been thought to be relatively stable over time; however, past research has shown that FHAs are more plastic than initially thought. As the product of the stress-activated hypothalamus–pituitary–adrenal axis, cortisol influences information processing at every level from stimulus perception to decision making and action. To investigate the influence of acute stress on FHAs, a team from the Biopsychology and the Cognitive Psychology lab from the Ruhr University Bochum invited 60 participants to the lab two times to perform three different tasks: a Banich-Belger task, a verbal and an emotional dichotic listening task. One session included a stress induction via the Trier Social Stress Test; the other session included a control procedure. We calculated across-field advantages (AFAs) in the Banich–Belger task and lateralization quotients for reaction times and responses per side in both dichotic listening tasks. There were no significant differences between the stress and control session in the dichotic listening tasks. In contrast, there was evidence for an influence of cortisol and sympathetic activation indicated by salivary alpha amylase changes on AFAs in the Banich–Belger task. This indicates that acute stress and the related increase in cortisol do not influence dichotic listening performance. However, stress does seem to affect interhemispheric integration of information.

Berretz, G., Packheiser, J., Wolf, O.T. et al. Dichotic listening performance and interhemispheric integration after stress exposure. Sci Rep 10, 20804 (2020). https://doi.org/10.1038/s41598-020-77708-5