The Yerkes-Dodson Law and Optimal Arousal
The Yerkes-Dodson law, proposed in 1908, demonstrates that the relationship between arousal and performance follows an inverted U-shape. Too little arousal leads to inattention, while too much causes anxiety and interference with processing. Optimal arousal varies with task difficulty: simple tasks benefit from high arousal, while complex cognitive tasks perform best at moderate arousal. The neural basis is thought to involve the noradrenergic system. In this account, noradrenaline released from the locus coeruleus, in appropriate amounts, improves the signal-to-noise ratio in the prefrontal cortex and supports working memory and attention control. However, excess noradrenaline suppresses prefrontal function, and amygdala-driven reflexive behavior tends to dominate.
- Simple task
- Complex cognitive task
The inverted U-shaped relationship shown in 1908. Simple tasks have their optimum toward high arousal, complex cognitive tasks toward moderate arousal. Curve heights indicate the shape of the relationship, not measured values.
The Dual Nature of Cortisol - Short-term Benefits and Long-term Harm
Cortisol, the stress hormone, is secreted from the adrenal cortex during acute stress. Short-term, it promotes glucose mobilization and increases brain energy supply. It also temporarily enhances hippocampal memory consolidation. However, chronically elevated cortisol levels are thought to cause hippocampal dendritic atrophy and suppress neurogenesis, which may lead to decreased memory and learning capacity. Prefrontal cortex synaptic density is also said to decrease, impairing executive functions (planning, judgment, inhibitory control). Under chronic stress, longer reaction times and lower working memory performance can also occur. Recovery takes time, but structural restoration is also said to be possible thanks to hippocampal plasticity.
Cognitive Biases Under Acute Stress
Under acute stress, an attention bias automatically draws focus toward threat-related stimuli. While evolutionarily adaptive, this becomes an interference factor in modern cognitive tasks. Under stress, decision-making can become conservative, with a stronger tendency to avoid risk. Confirmation bias is also said to be amplified, strengthening the tendency to selectively process information consistent with existing beliefs. In testing situations, stress-induced arousal amplifies time pressure perception, tending to cause a speed-biased shift in the speed-accuracy tradeoff. In that case, responses become faster while error rates rise. Recognizing this phenomenon and deliberately slowing your pace is thought to help.
Cognitive Reappraisal and Stress Inoculation Training
Cognitive reappraisal is an emotion regulation strategy that intentionally changes the interpretation of stressful situations. Reinterpreting 'threat' as 'challenge' is said to dampen the cortisol response and help maintain prefrontal cortex activity. In an fMRI study of healthy women, Drabant et al. (2009) reported that greater everyday use of reappraisal was related to lower amygdala activity and higher prefrontal activity while processing negative facial expressions. Stress Inoculation Training (SIT) involves gradually increasing stress intensity while acquiring coping skills. It is used in military training and surgical education, and a meta-analysis by Saunders et al. (1996) reported that it enhances performance under stress. In daily life, intentionally performing cognitive tasks under mild pressure serves as a simplified version of SIT.
How you view stress changes the response
Even facing the same event, how you view it changes the response of mind and body. There is a view that, rather than regarding stress uniformly as harmful, reinterpreting it as something that rouses you and draws out your power eases excessive tension and stabilizes performance. You interpret a pounding heart not as proof of anxiety but as a sign that the body is preparing for the real thing. Such a shift in view does not erase stress itself but is a practical device for getting along well with stress and making its power your ally.
Concrete Recovery Practices
Calming the stress response system helps cognitive function recover. Vagal nerve activation is a particularly fast-acting method; the 4-7-8 breathing technique (4-second inhale, 7-second hold, 8-second exhale) is expected to shift the body toward parasympathetic dominance and improve heart rate variability (HRV). Higher HRV correlates positively with cognitive flexibility and is used as one physiological indicator of stress resilience. Exercise is thought to promote hippocampal neurogenesis through BDNF secretion and to aid recovery from cortisol-induced damage. Social connection is also said to buffer the stress response through oxytocin release. Sleep is a particularly powerful recovery tool; during slow-wave sleep, cortisol is thought to reach its lowest levels and synaptic homeostasis maintenance to take place. A comprehensive recovery strategy combining these elements can form the foundation for sustained cognitive performance.