Task 5

Question 1

On what factors does the ranking in the hierarchies depends?

Answer 1

ranks depend on factors

• size
• strength
• age
• coalitional support within the group

Question 2

what is a dominance hierarchy?

Answer 2

hierachy in a group, where some individuals can displace others

• reproductive success is higher for high ranked vs. low
• for low ranked, there is high cost to get up, therefore stay down
• when stable: low ranked are more stressed
• when unstable: high ranked stressed, need all the time fight for their place

Question 3

What are the evidence of the Out of Africa model?

Answer 3

1. Morphology
   - AMH (anatomically modern human) all over the world look relatively like each other
2. Genetics of living humans
   - all current humans can be traced back to a small set of ancestors
3. Neanderthal DNA
   - AMH and Neanderthal did not reproduced offspring
   therefore NT genes are more similar to themselves than to AMH
   - if they mated, we must have found similar mutations in the mtDNA

Question 4

What makes humans different?

Answer 4

1. Meat eating
   - provides a lot of energy, can be used for the brain
   - smaller gut then herbivores
2. Tool use
3. Brain size
   - large brain size compared to other primates
4. Life history
   - lifespan has generally increased
   - increasing brain size associated with increased lifespan
5. Learning niche
   - use different strategies
6. Language
   - can communicate about what is going on and can make plans

Question 5

What is allometry?

Answer 5

The study of the relationship of body size to shape, anatomy, physiology and behavior
(allometric line is the expected brain size of an animal depending on those factors)

Brain size = C (W)^k
c and k = constant
w = body weight

• brain size grows more slowly than body size
• our brain is 5x larger than expected for mammals and 3x larger than for primates
  => we lie above the allometric line seen for mammals!

Question 6

What is the Encephalisation Quotient (EQ)?

Answer 6

EQ = actual brain weight / brain weight predicted from allometric line

=> its a better measure of intelligence than the absolute brain size
e.g. whales have a way bigger brain but we are more intelligent than whales

Question 7

Our human brain takes around 20 % of our energy, while it is only 2% of our whole body mass!

what strategies do we have for energy supply?

Answer 7

1. increase energy inputs relative to body size overall (eating meat, cooking food)
2. reduce energy in other bodily functions

Question 8

What is the Machiavellian intelligence hypothesis => social brain hypothesis (SBH)

Answer 8

Machiavellin intelligence hypothesis = old version

• hierachies, dominance
• need to keep track of whom is in higher rank and who is lower
• require cognition = face recognition

SBH = associate brain enlargement with increasingly large and complex social groups

evidence: relative brain size of the neocortex is corrected with social complexity in primates

Question 9

Social cognition

Answer 9

• early in evolutionary history also bonding between non- reproductive partners = friendship
• bonding between same sex and opposite sex

Question 10

Why are social demands so cognitively demanding?

Answer 10

because:
1. A lifelong monogamy is a risky commitment
- need to be careful whom to choose

2. it involves substantial postnatal parental investment and close coordination

Question 11

General intelligence hypothesis

Answer 11

• larger brains enable humans to perform all kinds of cognitive task more efficiently than other species
  => predicts no differences between physical and social cognition
  e.g. greater memory, faster learning, planning beforehand

Question 12

Adapted intelligence hypothesis

Answer 12

• cognitive abilities evolve through environmental challenges
  (ecological or social)

Question 13

Ecological intelligence hypothesis

Answer 13

• primates cognition evolved through challenging demands of foraging for seasonal fruits and resources
• need to remember the place where fruit last found (spatial map)
• seasonal fruit, toxic fruits
  e. g. searching for berries, or cracking nuts etc

Question 14

social intelligence hypothesis

is kinda similar to SBH

Answer 14

• cognition evolved through challenging demands of complex social life and of constant competition and cooperation

Question 15

cultural intelligence hypothesis

Answer 15

• humans cognitive skills due to species- specific set of social-cognitive skill for participating and exchanging knowledge in cultural groups

Question 16

What is the outcome of the experiment testing children with monkeys in physical and social domain?

Answer 16

• chimpanzees and children do not differ much in physical domain
• BUT they significantly differ in social domain
• human beings are more cooperators than monkeys

=> strong support for the cultural intelligence hypothesis
(human being have evolved some specialized social-cognitce skills for living and exchanging knowledge

=> NO support for general intelligence hypothesis
(human cognition differs only in general cognitive processes such as memory, learning etc

Question 17

Is fruit eating responsible for larger brains? (article)

Answer 17

• fruit is the only thing that predicts larger brain size
• leaves e.g. long digesting time, nutrients looked in thick cell walls
• fruit are easy to digest, give a big amount of energy
• eating fruit is more cognitive challenging than eating leaves
• developing larger brains to deal with these complex conditions
• Diet and sociality are not alternative explanations => they are complementary

Question 18

A gene (ARHGAP11B) makes human brain unique (Article)

Answer 18

• gene produces more brain cells in neocortex => region central to reasoning, language and sensory perception

evidence:
- injected in mice = grew crinkled brain surface like humans

but intelligence or high cognition does not only depend on this gene, it depends on many genes to create a functional network