Enhanced emotional regulation after provocation through stress- the influence of acute stress and provocation on affective picture processing: an event-related potential study

The stress hormone cortisol has been identified as an important factor promoting aggression. Taken by itself, cortisol and aggression have been shown to alter the processing of social relevant information, the latter being crucial in the development of a vicious cycle of violence. However, the mutual influence of cortisol and aggression on information processing has hardly been examined, even though this might provide insight into the underlying mechanisms of the escalation and the persistence of aggressive behavior, once it has begun. Thus, the present study investigated the effect of stress-induced rise in cortisol and provoked aggression on affective picture processing. 71 subjects were randomly assigned to a stress or a control condition and were either highly or mildly provoked during the subsequent Taylor Aggression Paradigm. Next, 144 pictures with positive, negative or aggressive content were presented. Meanwhile the EEG was recorded and acute levels of salivary cortisol were collected. Results revealed that cortisol and provocation jointly altered especially later event-related components (P300, slow waves), albeit in opposite direction. While high provocation resulted in overall enhanced amplitudes in the control group, it led to reduced amplitudes to all affective pictures in subjects with stress-induced increase of cortisol levels, indicating a general emotional regulation. These results suggest that adaptive controlling mechanisms are activated to face the mutual impact of stress and provocation, underlining the impact of cortisol in the context of aggression.