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

This study investigates how acute psycho-physiological stress affects working memory performance, specifically examining whether these effects depend on the difficulty of the task (memory load) and the duration of the time information must be held (retention interval). The researchers aimed to determine if moderate stress acts as a performance enhancer or a hindrance in a controlled laboratory setting.

Researchers recruited twelve healthy young men to perform a modified Sternberg working memory task under two conditions: a stress condition and a control condition. The stress condition combined a socially evaluated cold pressor test (SECPT) with a modified Trier Social Stress Test (TSST) to induce a normal, acute stress response. Participants were evaluated on their reaction time and accuracy across varying memory loads (two vs. five images) and retention intervals (two vs. eight seconds). Physiological markers, including salivary cortisol, heart rate, blood pressure, and near-infrared spectroscopy (NIRS) of the prefrontal cortex, were monitored to confirm the effectiveness of the stress induction.

Contrary to the common belief that stress universally impairs cognitive function, this study found that acute, normal-intensity stress can actually benefit working memory. Specifically, participants exhibited faster reaction times without a decrease in accuracy during high-load memory tasks. The researchers suggest that this effect may be due to an inverted-U relationship between cortisol levels and memory, where moderate stress acts as 'eustress' that optimizes performance. Furthermore, the data indicate that under high-load stress, participants may rely more heavily on long-term memory to support their performance, particularly during longer retention intervals.

Understanding the nuanced relationship between stress and cognitive performance is critical for workplace ergonomics. By identifying that moderate stress can enhance performance under high task demands, organizations may be better equipped to design job tasks and manage stress levels to minimize human error and maximize productivity. This suggests that rather than eliminating all stress, the goal should be to maintain stress within an optimal range that supports cognitive efficiency.