PHIL 2420 - Week 10: The self-domesticated species hypothesis and the cooking ape hypothesis

What is Wrangham’s major text?

The Goodness Paradox

What question does The Goodness Paradox answer?

why humans can show evil & love to one another

What explains why humans can show evil & love to one another?

innately…

• bad

v.s.

• good

What explains the innate good belief?

social / environmental force

What explains the innately bad belief?

law / state / education

What does Wrangham believe about why humans can show evil & love to one another?

both innately…

• good

• bad

What explains Wrangham’s belief about why humans can show evil & love to one another?

biology

What is a Wrangham strategy example?

comparative anatomy

What does Wrangham believe are some examples of human & ape differences?

• social structure

What are some examples of human & ape similarities?

• self-medication

What species does The Goodness Paradox compare?

• chimpanzee

v.s.

• bonobo

What does Wrangham believe are some examples of chimpanzee & bonobo differences?

chimpanzee

• male >

• violent

  • sex < aggression

• reactive aggression

• big teeth

v.s.

bonobo

• female >

• nonviolent

  • sex > aggression

• self-domesticated species

• small face

What does Wrangham believe about humans & chimpanzees / bonobos?

see both behaviours

What does Wrangham believe are human & chimpanzee / bonobo similarities?

chimpanzee

• power

• violence

• competition

v.s.

bonobo

• tolerance

• egalitarianism

• sexuality

What are the aggression types?

• reactive

v.s.

• proactive

What is The Goodness Paradox’ main idea?

human = self-domesticated earlier & wilder ancestor version

What is the human / bonobo / chimpanzee violence order?

human < bonobo < chimpanzee

What is the Goodness Paradox?

• low violence in society

v.s.

• high violence between societies

What explains Wrangham’s aggression belief?

localization →  

What does Aristotle believe about human domestication?

some…

• wild

v.s.

• domesticated

What does Theophrastus believe about human domestication?

all…

• domesticated

What does Blumenbach believe about human domestication?

only truly domesticated animal

What explains Blumenbach's human domestication belief?

supreme being

What does Mead & Boas believe about human domestication?

• domesticated

  • Boas: self-domesticated

What is domestication syndrome?

domesticated animal trait group

• behaviour

• anatomy

• morphology

What does Leach believe about domestication syndrome?

in humans

What explains Leach’s domestication syndrome belief?

• light bone

• short face

• sexual dimorphism

• small brain

What is sexual dimorphism?

male ≈ female

• size

• height

What does domestication syndrome cause?

parallel adaptation

What is parallel adaptation?

separate evolution

What does Wrangham believe about domestication syndrome?

some traits = byproducts

What explains Wrangham’s domestication syndrome belief?

domestication pressure

What experiment does Belyaev do?

1. select calm silver fox
   * 100 female & 30 male

2. breed pup generation

3. select calm silver fox
   * 20% of females & 5% of males

v.s.

4. control group

What are the Belyaev experiment outcomes?

• 3rd generation: some weren’t aggressive

• 4th generation: some wag tail

• 6th generation: some whimper

• 10th generation: 18% ‘elite’

• 20th generation: double %

• 30th generation: double %

What does Belyaev conclude from his experiment?

• brain

• hormone

• physiology

• earlier change = wider effect

What byproducts does Belyaev notice from his experiment?

• white spot

• breeding season loss

• floppy ear

• short tail & leg

• over / under … bite

What does Belyaev believe about domestication syndrome?

useless

• produced when against reactive aggression

What explains Belyaev’s domestication syndrome belief?

question: what if domesticated animals were set free?

answer: no change

What does Belyaev believe are the domestication syndrome biological systems?

• neural crest cell migration

• thyroid hormone change

What does Wrangham believe are some examples of chimpanzee & bonobo similarities?

• forest life

• few dozen group size

• alliance shift

• territory defence

• daughter migration

• alloparent

What does Wrangham believe about bonobos?

domestication syndrome

What does Wrangham believe causes peace to be favoured over aggression?

female power

What explains Wrangham’s peace belief?

female bonobos…

• gang up on male bonobos

• form defences

• choose less aggressive males

What is the domestication syndrome & aggression relation?

if domestication syndrome, against aggression

What does Wrangham believe causes reduced aggression?

execution hypothesis

→ antisocial removal

What explains Wrangham’s reduced aggression belief?

can’t reproduce

What is Wrangham’s execution hypothesis?

violent male punishment

• male coalition killed alpha males

What explains Wrangham’s execution hypothesis?

• language

  • weapon use

What is Wrangham’s other major text?

Catching Fire

What was the homo genus’ main invention?

bipedal

What selective forces led to the homo erectus?

meat eating hypothesis

What explains why Wrangham’s meat eating hypothesis led to the homo erectus?

• opportunistically eat raw meat

• use tool to butcher carcass

• run after prey / look for carcass

What are some examples of gaps in Wrangham’s meat eating hypothesis?

• gather sustenance 

What are the big lineage transformations?

1. australopithecine → homo habilis

2. homo habilis → homo erectus

What does Wrangham believe causes the homo habilis → homo erectus transformation?

fire & cooking mastery

What does Darwin believe are the most important human inventions?

• fire

• language

What explains Wrangham’s fire & cooking mastery belief?

increase energy

→ release nutrient

• anatomy

• history

• ecology

• psychology

What does Wrangham believe traces fire?

biology > archaeology

What explains Wrangham’s biology belief?

small teeth & short guts → diet change diet change → small teeth & short guts