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Modern Wisdom

Dr Richard Wrangham - The Incredible Evolution Of Human Violence

Sat Feb 25 2023
evolutionaggressionhuman naturepower dynamicsmale roles


This episode explores the evolution of human aggression, from our capacity for both kindness and ruthlessness to the development of proactive and reactive aggression. It delves into the correlation between anatomical and psychological changes, the influence of institutional patriarchy on aggression, and the role of morality in human societies. The episode also examines power dynamics and male dominance, changing dynamics and male roles in society, and the challenges and uncertainties surrounding male roles in the future.


Evolutionary Origins

Humans have evolved with both aggressive and tolerant sides to their personality, and our capacity for aggression can be traced back millions of years to the genus Homo.

Selective Breeding

Selective breeding experiments with animals have shown that selecting against reactive aggression can lead to traits associated with domestication syndrome, such as reduced aggression and anatomical changes.

Influence of Patriarchy

Institutional patriarchy has shaped human societies, with moral principles often working to benefit the group of males in power.

Changing Dynamics

As resources become more abundant and women achieve greater independence, traditional male roles are being challenged and redefined.

Uncertainties in Male Roles

Advancements in reproductive technology and changing societal dynamics raise questions about the future of male roles and the concept of masculinity.


  1. Evolution of Human Aggression
  2. Development of Aggression in Early Humans
  3. Evolutionary Changes in Human Aggression
  4. Correlations Between Anatomical and Psychological Changes
  5. Influence of Institutional Patriarchy on Aggression
  6. The Role of Morality in Human Aggression
  7. Power Dynamics and Male Dominance
  8. Changing Dynamics and Male Roles in Society
  9. The Future of Male Roles in Society
  10. Challenges and Uncertainties in Male Roles

Evolution of Human Aggression

00:00 - 09:03

  • Humans have the capacity for incredible benevolence and kindness, but are also able to execute other members of our species with a uniquely effective ruthlessness.
  • Evolution has given humans differing capacities compared to chimps and apes.
  • Humans are responsible for more deaths of their own species than other animals.
  • Humans have both aggressive and tolerant sides to their personality.
  • Society is not solely responsible for taming or making humans aggressive.
  • Two philosophers, Rousseau and Hobbes, had opposing views on human aggression.
  • Modern science allows us to understand human nature in a broader perspective by studying our close relatives, the great apes.
  • Evolution works in fascinating ways to generate different levels and types of aggression in different species.
  • The evolutionary story of human aggression can be traced back two million years when the genus Homo arose.

Development of Aggression in Early Humans

08:35 - 18:08

  • Early humans, two million years ago, were good hunters and killers of their own species.
  • Humans have always attacked and killed other humans through the advantage of numbers or tactical arrangements.
  • Around three or four hundred thousand years ago, humans developed sufficiently skilled language to form gangs against members of their own group.
  • Forming a gang against a member of your own group is complicated because there is a risk that the gang may turn against you.
  • The ability to execute another member of your own group changed society by eliminating bullies who exerted power over others.
  • This selection for non-bullies inadvertently reduced aggressive tendencies in humans.
  • There are two kinds of aggression in animals: proactive (premeditated) and reactive (impulsive).
  • Proactive aggression is deliberate and goal-oriented, while reactive aggression is defensive and emotionally aroused.
  • Proactive and reactive aggression can be controlled differently in the brain and follow different evolutionary trajectories.

Evolutionary Changes in Human Aggression

17:40 - 26:25

  • Proactive and reactive aggression are controlled differently in the brain and can have different evolutionary trajectories.
  • Around 300,000 years ago, proactive aggression continued while reactive aggression decreased in humans.
  • Selective breeding experiments with animals have shown that selecting against reactive aggression can lead to traits associated with domestication syndrome, such as white patches of fur and floppy ears.
  • Humans also exhibit some features of the domestication syndrome, including relatively slender bones, shorter faces, and males becoming more female-like.
  • Language and advanced communication allowed for better coordination among humans and a self-domestication process where aggressive individuals were pruned off by the group.
  • Over time, this led to anatomical changes in humans, such as shorter faces, less aggressive jaws, reduced brow ridge, and lower bone density in males.
  • Humans have been responsible for their own evolutionary trajectory for the last quarter of a million years or more.

Correlations Between Anatomical and Psychological Changes

25:56 - 34:29

  • Psychological changes in our ancestors cannot be directly studied, but can be inferred through correlations with anatomical changes.
  • The breadth of the face in relation to its length is correlated with aggression in males.
  • A study on ice hockey players found that those with broader faces spent more time in the penalty box for being too aggressive.
  • There was a positive relationship between breadth of the face and penalty box minutes in every team studied, although not statistically significant within each team.
  • Females have likely undergone significant changes compared to their APISH past, becoming more feminized and less like males.
  • The reasons behind these changes are not clear, but it could be due to selection on males or intense selection on females to become less aggressive.
  • Increased coordination and co-allitional capacity among females may have led to further changes during that period.

Influence of Institutional Patriarchy on Aggression

34:00 - 42:57

  • Institutional patriarchy refers to rules within a society that benefit men at the expense of women.
  • An ancestral example is that females who have adulterous relationships are punished more heavily than males.
  • Women with more sons tend to condemn promiscuity more, as they want to reduce male parental uncertainty.
  • There may be motivation for women to condemn promiscuous women due to intra-sexual competition.
  • There are pressures and incentives for women to tune down promiscuity.
  • The Alpha Alliance is a group of males responsible for killing the tyrant and becoming leaders of society.
  • This leads to conformity and imposes pressures on females who go against the norms.
  • Hunter-gatherer ethnographies show accounts of women being executed for adultery or even witnessing sacred rituals of men.
  • The emergence of the Alpha Alliance coincides with the evolution of moral principles based on right and wrong behavior.

The Role of Morality in Human Aggression

42:32 - 51:56

  • Morality is derived from power dynamics and the concept of right and wrong is based on what benefits the alpha allows.
  • Our sense of right and wrong is a way to avoid being killed by small groups of alpha males.
  • Children learn to conform and impose rules on each other at a young age, suggesting that norm psychology is innate.
  • There may be some basic principles like theft and harm that are universally considered wrong, but many moral concepts are fluid.
  • There might be a genetic predisposition towards fairness or disgust as part of our sense of right and wrong.
  • Bonobos have less proactive aggression than chimpanzees, indicating selection against it in bonobos.
  • In bonobos, females have power in the form of female-led coalitions that can impose damage on males who misbehave.
  • The self-domestication of bonobos aims to stop males from being aggressive towards females rather than eliminating alpha males like in humans.

Power Dynamics and Male Dominance

51:30 - 1:00:38

  • Bonobos lack the ability for subordinated males to form confident coalitions and attack the alpha male
  • Females in bonobo societies spend time together on a relatively permanent basis, allowing them to coordinate attacks on dominant males
  • Human societies are designed around what benefits the group of males in power
  • Moral principles in human societies work for the benefit of the male group as a whole
  • Religions are often biased towards male interests
  • The institution of religion may serve as a storytelling justification for male dominance
  • Male control over cosmology and restricted areas is important to maintain complete control over society
  • Extreme actions like kin executions reflect the power of dominating groups to impose their own morality
  • Capital punishment has had an extraordinary revolutionary effect on human society's complexities and patterns
  • The development of capital punishment has changed power dynamics and enforced rules within societies

Changing Dynamics and Male Roles in Society

1:00:14 - 1:08:58

  • In a period of surplus resources, the local ecology and mating market could influence the response to aggression.
  • Male desires and motivations are driven by power and access to females.
  • Emperors in various societies have had immense power and large harems of women.
  • The trickle-down effect of power leads to competition for females.
  • The agricultural revolution and accumulation of resources changed how humans relate to each other.
  • In Northern Australia, as resources became more abundant, women supported men with multiple wives.
  • When there is a surplus of resources, women are less pressured to date suboptimally or rely on male protection.
  • Modern dynamics include relative peace, condemnation of aggression, and increasing female achievement and independence.
  • These dynamics raise questions about male roles in society.

The Future of Male Roles in Society

1:08:30 - 1:16:59

  • The rise of Andrew Tate and his philosophy raises questions about male roles and the future of males in society.
  • There is a parallel between the dynamics of a small hunter-gatherer society and our modern society, where moral and institutional systems keep violence in check.
  • It is uncertain whether these rules will become too burdensome for men's spontaneous tendencies, potentially leading to a breakdown of the system.
  • Men's traditional roles are no longer required as women outperform men in education and knowledge-based office work.
  • The previous roles that men relied on, such as big game hunting or commanding serfs, have fallen away.
  • Morality was built to protect men's interests, but now that those interests have been emancipated, gatekeeping elements have eroded.
  • Women no longer need men for resources, further challenging traditional masculinity.
  • Definitions and roles within society need to adapt to reflect the changing ecology and environment.
  • The concept of masculinity may become meaningless as its constituent parts dissolve over time.
  • Men still play an important role as fathers of sons.

Challenges and Uncertainties in Male Roles

1:16:53 - 1:21:38

  • Being a stay-at-home dad is not considered high status for men.
  • Men who are financially dependent on their partners are more likely to experience erectile dysfunction and divorce.
  • Women are becoming increasingly independent and may not need men in the future.
  • Advancements in reproductive technology may eliminate the need for sperm in reproduction.
  • The Y chromosome, which is unique to males, is associated with violence and aggression.
  • There could be ethical concerns about removing the Y chromosome from future generations.
  • Human morality may not have evolved as a by-product of alpha males' behavior.
  • The interviewee studies chimpanzees and has a website called Kibale Chimpanzee Project.