Problem 5

Question 1

Dominance hierarchies

Answer 1

Refers to an ordering of the members of a social group

1. Some individuals are “higher” in rank than others and are constantly able to displace others from a resource
2. The rank is dynamic and can be challenged (by fighting) and reversed
3. Ranks in the hierarchy will depend on size, strength, age, coalition support

Question 2

Social brain hypothesis

Answer 2

Refers to the idea that maintaining social relationships requires devoted brain mechanisms

–> social species will tend to have relatively larger brains than non social ones

=> a bigger brain size must therefore have developed as a result of bigger group size

Question 3

There is fossil evidence for a series of intermediate forms between ourselves and the chimpanzees, which tend to have more human like characteristics over time and all of which are now extinct.

What are those major branches on the primate phylogeny ?

Answer 3

1. Haplorrhine
2. Strepsirrhine
3. Tarsier
4. Platyrrhine
5. Catarrhine

–> old world monkeys + apes

Question 4

Gibbons

Answer 4

Are a type of ape that from longterm pair bonds + their territorial social groups consist of monogamous pair, including an offspring

–> specialized in their hand, arm, shoulder anatomy for brachiation

Question 5

Brachiation

Answer 5

Refers to locomotion through trees by swiping from the arms, like a child in monkeys bars

Question 6

Hominin

Answer 6

Refers to a member of the group consisting of humans + their extinct relatives

–> human ancestors

Question 7

Australopithecines

Answer 7

Refer to extinct hominins found in africa who were more bipedal than chimpanzees, but had smaller brains

–> specialized in processing coarse plant foods

Question 8

For which reasons is the early “Homo” significant ? (2.5m y ago)

Answer 8

1. First animals where the brain size begins to move clearly away from that of chimpanzees + towards human pattern
2. Around their time of appearance some tools start to appear
3. First hominins to appear outside of africa

–> begun to depend on meat to a greater extent

Question 9

Archaics

(800.000 y ago)

Answer 9

Refer to a more developed form of hominins that appeared in africa first

–> brain + body size were within the range of humans

Question 10

Neanderthal

(300.000 y ago)

Answer 10

I a branch of the archaics that first appeared in europe and lived until relatively recently

Question 11

Out of africa model

Answer 11

The model proposes that

1. All living humans seem to have descended from a small population living in Africa within the last 200.000 years

–> morphology

2. AMH (anatomically modern human) is a new species that replaced the other living hominins without interbreeding

–> emphasis on the “single origin”

Question 12

Pleistocene

Answer 12

Refers to the “Ice Age”, which is a geological epoch that included the world’s most recent period of glaciations

–> 1.8m to 10.000y ago

Question 13

Holocene

Answer 13

Refers to the current geological epoch, beginning 10.000 years ago

–> warm period

Question 14

Compared to our closest relatives, humans show remarked changes in certain domains

What makes humans different ? What distinguishes them from the hominins ?

Answer 14

1. Great dependency on MEAT EATING (Diet) ​

• reduced gut relative to apes, which are usually smaller in carnivores than herbivores
• Moore metabolic energy left for brain

2. The extent of dependency on TOOLS
   * related to meat eating
3. LARGE BRAIN SIZE relative to chimpanzees
   * increase from australopithecine - homo - archaics
4. High skill foraging/SKILL LEARNING
   * ability to occupy an incredible breadth of different environments in many ingenious ways
5. LIFE HISTORY
   * increased lifespan + longer childhood
6. LANGUAGE use
   * productive, meaningful, social learning

Question 15

Humans belong to the primates.

More specifically to the … ?

Answer 15

Haplorrhines, gibbons + great apes

–> their closest living relatives are the chimpanzees

Question 16

Cultural intelligence hypothesis

Answer 16

Argues that the human’s unique cognitive skills stem mainly from the species-specific set of social-cognitive skills for participating and exchanging knowledge in cultural groups

–> supported as children + chimpanzees have very similar skills when it comes to dealing with the physical world but children use more sophisticated skills

Question 17

General intelligence hypothesis

Answer 17

Predict that larger brains enable more efficient use of all cognitive operations

Question 18

Ecological intelligence hypothesis

Answer 18

Cognition evolved in response to challenging demands of foraging seasonal fruits & resources embedded in substrates

–> related to fruit hypothesis

Question 19

Adapted intelligence hypothesis

Answer 19

Cognitive abilities evolve in response to relatively specific environmental challenges

Question 20

Machiavellian intelligence hypothesis

Answer 20

Proposed that what differentiates primates from all other species was the complexity of their social lives and environment

–> Since the term Machiavellian was misleading for many, it got replaced by the social brain hypothesis (SBH)

Question 21

Expensive tissue hypothesis

Answer 21

States that increases in brain size of hominis must have been balanced by a reduction of demands of other organs

–> part of the ecological intelligence hypothesis

ex.: gut reduction

Question 22

Aboreal theory

Answer 22

Claims that primates evolved from their ancestors by adapting to arboreal life (living on trees)

• moving + feeding on land required stereoscopic vision and dextrous hands, both of which in turn required a large brain to coordinate and control
• criticized as carnivores need to kill too which requires the same abilities

Question 23

Fruit hypothesis

Answer 23

States that fruit diet allowed rather than drove the evolution of big brains

Question 24

Allometry

Answer 24

Refers to the predictable relationship between brain and body size in mammals

ex.: if a mouse would grow as big as a human, its brain size would increase accordingly

FORMULA: C x (body size)^k

C= brain weight

W= body size

k= constant

Question 25

Encephalisation quotient (EQ)

Answer 25

Refers to the departure of the brain size to the allometric line

–> comparable to the standard deviation

Question 26

Chihuahua fallacy

(Criticism on EQ)

Answer 26

States that Brain size does not predict intelligence as intelligence is way too complex to have such a simple relationship

ex.: Chihuahuas could become really small but keep their brain size

–> EQ shows that it is larger than expected/Predicted

Question 27

Which ones are the great apes ?

Answer 27

1. Orang Utans
2. Gorillas
3. Chimpanzees

Question 28

Which kinds of Hominins are there ?

Answer 28

1. Australopithecines
2. Early Homos
3. Archaics

Question 29

How does the Gene “ARHGAP11B” make human brains more unique ?

Answer 29

It is a modified version of common DNA strand found in simple organisms that drives the expansion of the brain by increasing the number of neurons in the neocortex

Question 30

Criticism on the gene “ARHGAP11B” ? Does it generally account for human intelligence ?

Answer 30

Gene is not sufficient enough to explain the phenomenon of intelligence

–> intelligence is polygenic, thus needs many genes to account for it

Question 31

What is Dunbars explanation on why the energy gained from the fruit diet (Fruit hypothesis) is directed toward the brain ?

Answer 31

According to him, living in big groups enables us to better fight predators

Question 32

What is DeCasiens explanation on why the energy gained from the fruit diet is directed toward the brain ?

Answer 32

According to him, fruit eating is more cognitively challenging

–> one needs more navigation skills

Question 33

There are new genetic variations that evolved over the past 7 million years after the split with chimpanzees.

Which are those and how did they make the human brain more unique ?

Answer 33

HAR1

–> cortical expansion, increased cortical control of behavior

FOXP2

–> enhances the capacity to speak + learn a language

SEGAP2

–> enhances learning