Effects of psychosocial stress on prosociality: the moderating role of current life stress and thought control.

To date, only a few studies have examined whether and when stressed individuals are still prosocially motivated and willing to help others, which is in contrast to the relevance and importance that helping others has for our society. The present study investigates the impact of affective and biopsychological acute stress responses on prosociality (prosocial motivation, helping behavior) under controlled laboratory conditions. In addition, it was examined whether this relationship is affected by individuals' current life stress and the cognitive ability to keep stress-related thoughts at bay. To induce acute stress responses (heart rate, negative affect, salivary alpha-amylase, cortisol), 55 individuals (28 women, M  = 24 years old, SD  = 4.53) were exposed to the Trier Social Stress Test (TSST). Current life stress (cortisol) was assessed over two days of participants' everyday lives. Thought control ability was assessed with the think/no-think paradigm and was additionally manipulated after the acute stress intervention (TSST) via instructions. The results showed that acute stress was positively associated with prosociality. Specifically, negative affect was positively related to prosocial motivation and salivary alpha-amylase was positively associated with helping behavior. Current life stress moderated the relationship between salivary cortisol and helping behavior: the association was positive at low levels of current life stress. The instruction to control one's thoughts but not participants' general ability to do so reduced stress responses (negative affect). In sum, the findings suggest that prosociality increases following acute stress and that this effect depends on the level of current life stress. Additionally, adopting the strategy of controlling stress-related thoughts was found to be promising for attenuating individuals' stress responses.