Stress can trigger aggression not only as a defensive reaction but also as a way to reduce internal tension. This pattern is observed in both animals and humans and has a clear neurobiological basis.
🐁 In Animals
- In rats, stressors such as electric shocks lead to increased glucocorticoid levels and blood pressure.
- Chronic exposure can cause stress-induced gastric ulcers.
- One of the most effective ways for a rat to reduce stress is to bite another rat.
- This behavior suppresses the release of corticotropin-releasing hormone (CRH), which activates the hypothalamic-pituitary-adrenal (HPA) axis.
🐒 In Primates
- Among baboons, over 40% of aggression cases are classified as displaced aggression.
- Dominant males who redirect aggression after a defeat tend to have 15–20% lower glucocorticoid levels than those who do not.
- Displaced aggression serves both a social regulation function and helps reduce physiological stress in the aggressor.
👤 In Humans
- During the 2008–2009 economic recession in the U.S.:
- Domestic violence incidents increased by 9–12% in some regions.
- Police received more calls related to family conflict.
- A study of 900 NFL games in the U.S. showed:
- After an unexpected loss of the local team, domestic violence incidents rose by about 10%.
- If the loss occurred in a playoff game, the increase was 13%.
- After a championship final loss, incidents rose by up to 20%.
🧬 Biological Mechanism
- Aggressive behavior activates dopaminergic reward pathways in the brain, producing short-term relief.
- This reduces hypothalamic activity and suppresses stress hormone release.
- In animals, this clearly reduces physiological markers of stress; in humans, it may create a subjective sense of control or relief.
