A normal intensity level of psycho-physiological stress can benefit working memory performance at high load

Abstract In recent years, the effects of stress on adaptation and human performance have received considerable attention in medical literature and in occupational fields. In this study, we employed an acute psycho-physiological laboratory stressor, which is similar to real life stressful conditions and is capable of reliably eliciting the normal range of stress effects. The primary goal of the present study was to investigate whether the effect of stress on working memory performance depends on the number of images that need to be maintained (memory load), and the duration of the retention interval. By manipulating the number of images and the length of the retention interval of the modified Stenberg working memory test, we altered the task difficulty and examined the consequent effects on behavior. Twelve young students were submitted to a stressful condition one day and a control condition on another day. The stressor used included a physiological factor (socially evaluated cold pressor test) and a psychosocial factor (modified version of trier social stress test). The sympathetic nervous system and hypothalamic–pituitary–adrenal axis activation were assessed by heart rate and salivary cortisol. It was found that this procedure, which involves exposure to a normal intensity level of psycho-physiological stress, can demonstrate the beneficial effect of stress on reaction time without decreasing accuracy at high memory loads, but not at low memory loads. Relevance to industry Managing stress in the workplace is important for decreasing human errors. Workers' performances can be improved if they receive appropriate levels of stress and task difficulty. If so, they might gain an advantage as long-term memory can be supported in addition to working memory.