Behave Summary

Behave is a wide-ranging study of why human beings act with kindness, cruelty, courage, fear, cooperation or aggression. Sapolsky argues that no human action has only one cause. To understand a person’s behaviour, we must examine what happened seconds before the action, the person’s hormones and brain activity, childhood experiences, social environment, culture, evolutionary history and even conditions experienced by earlier generations. The book rejects simple explanations such as “he was born violent” or “she is naturally kind.” Human behaviour emerges from a complicated interaction between biology, experience and society.

• Behaviour has many causes: One action may result from biology, upbringing, circumstances and culture at the same time.
• The brain responds quickly: Fear, anger and attraction may begin before conscious reasoning takes place.
• Hormones influence rather than control: Testosterone, cortisol and other hormones affect tendencies but do not determine behaviour completely.
• Childhood matters greatly: Early care, stress, neglect and trauma can shape later emotional responses.
• Culture shapes the mind: Ideas about honour, shame, loyalty and justice vary across societies.
• Stress changes decisions: Long-term stress can damage judgment, health and emotional control.
• Human beings can be violent and compassionate: Biology gives us the capacity for both cruelty and cooperation.
• Context changes morality: People often judge the same action differently depending on who performs it and against whom.
• Change remains possible: Human behaviour is flexible because the brain continues to respond to experience.
• Important quotation: “Anyone who says that our worst behaviors are inevitable knows too little about primates, including us.” The line rejects the belief that violence is unavoidable.