Acute stress enhances the sensitivity for facial emotions: a signal detection approach

Facial emotion recognition is an important prerequisite for social cognition. There is, however, limited evidence on how the ability to detect facial emotions is influenced by acute stress and the associated physiological reactions. In this study, two groups of healthy male participants were either exposed to a psychosocial stressor - an adaptation of the Trier Social Stress Test in virtual reality (n = 23) - or a non-stressful control task in the virtual environment (n = 20). Afterwards, both groups completed a computerized facial recognition task based on the signal detection theory presenting happy vs. angry faces with three different expression intensities. Saliva samples were taken at seven time points over the course of the experiment and used to analyze concentrations of free salivary cortisol and alpha amylase. Analyses using repeated-measures analyses of variance revealed a significant increase in emotion detection performance and significantly shorter response latencies in the stress group independent of emotional valence or emotion intensity. However, increased task performance in the stress group could not be predicted by stress-induced cortisol or alpha amylase secretion. The results suggest that enhanced detection of emotional cues after stress might be an adaptive response as an increased sensitivity to social cues might help individuals to detect potential threats or sources of social support in their social environment. Lay Summary Socially evaluative stress facilitates the subsequent recognition of emotions. After having performed a task in a virtual environment, two groups of participants were asked to detect emotion expressions on pictures of faces that were presented to them on a computer screen. Statistical comparison of groups indicates that the group that had previously been subjected to a stressful job interview showed better results and became faster in detecting displayed emotions than the control group that had previously performed a non-stressful task.