Cognition psychologists at the Ruhr-Universit-t together with colleagues from the University Hospital Bergmannsheil (Prof. Dr. Martin Tegenthoff) have discovered why stressed persons are more likely to lapse back into habits than to behave goal-directed. The team of PD Dr. Lars Schwabe and Prof. Dr. Oliver Wolf from the Institute for Cognitive Neuroscience have mimicked a stress situation in the body using drugs. They then examined the brain activity using functional MRI scanning. The researchers have now reported in the Journal of Neuroscience that the interaction of the stress hormones hydrocortisone and noradrenaline shut down the activity of brain regions for goal-directed behaviour. The brain regions responsible for habitual behaviour remained unaffected.
Two stress hormones in use
In order to test the different stress hormones, the cognition psychologists used three substances - a placebo, the stress hormone hydrocortisone and yohimbine, which ensures that the stress hormone noradrenaline stays active longer. Part of the volunteers received hydrocortisone alone or just yohimbine, others both substances. A fourth group were administered a placebo. Altogether, the data of 69 volunteers was included in the study.
Goal-directed behaviour and habits investigated in the experiment