Human Overview

Question 1

What are human traits that are unique compared to other primates?

Answer 1

1) Bipedalism
2) Aerobic endurance capacity
3) Bigger brains
4) More hypercooperative/prosocial and less aggressive

Question 2

What is aggression?

Answer 2

An adaptive strategy among most primates to increase reproductive success

Question 3

Who were the first hominins?

Answer 3

1) Ardipithecus ramidus (4.4 mya)
2) Australopithecus afarensis (LUCY) (3.5 mya)

Question 4

Describe the characteristics of Ardipithecus ramidus

Answer 4

1) Bipedal in the trees and on the ground (divergent hallux)
2) Chimpanzee-sized brain

Question 5

Describe the characteristics of Australopithecus afarensis (LUCY)?

Answer 5

1) Human traits from the waist-down (bipedalism)
2) Chimpanzee traits from the waist up (brain, gut size)
3) High sexual dimorphism in body size but not in canines

Question 6

What is shared intentionality?

Answer 6

1) Ability and motivation to engage with others in collaborative, cooperative activities with joint goals and intention
2) The source of all cognitive achievements

Question 7

What does Rousseau say about human nature?

Answer 7

Humans are naturally cooperative and unaggressive, where aggression only arose with civilization

Question 8

What does Hobbes say about human nature?

Answer 8

Humans are naturally competitive and violent, where stronger governments are required to tame human instincts

Question 9

What are the 2 types of aggression?

Answer 9

1) Reactive
2) Proactive

Question 10

What is reactive aggression?

Answer 10

Sudden (often in response to fear or contest), where the target can easily be switched

Question 11

What is proactive aggression?

Answer 11

Pre-planned according to desire, with a fixed target

Question 12

What happened during human evolution in terms of aggression?

Answer 12

Reactive aggression has been reduced and proactive aggression is more prominent

Question 13

What did Hill and Hurtado observe with the Ache (hunter-gatherer) foragers?

Answer 13

In the 17 years they were there, they never observed a scuffle between Ache men

Question 14

What is the rate of male “scuffles” in human males vs chimpanzees?

Answer 14

Human males “scuffle” at ~1/1000th of the chimpanzee rate

Question 15

What is self-domestication?

Answer 15

Evolution of a reduced propensity for reactive aggression (compared to an immediate ancestor) without the active involvement of another species

Question 16

What is the domestication syndrome?

Answer 16

Domesticated animals tend to look a particular way, even though those phenotypic traits are not directly selected for (pleiotropy)

Question 17

What may indirectly occur when we select for reduced aggression, fear, and stress response in animals?

Answer 17

1) Reduced brain size
2) Reduced muzzles, smaller teeth
3) White patches

Question 18

For bonobos, where reduced aggression has been selected for, what are the associated unselected traits?

Answer 18

1) Shorter canines
2) Cranio-facial feminization (reduced sexual dimorphism)
3) Paedomorphic (juvenile-like) characteristics: white tuft maintained later, later development of inhibition, pink lips

Question 19

What is the anatomical evidence to suggest that humans were self-domesticated?

Answer 19

AMH have smaller teeth, a flatter bow ridge, more circular crania, reduced jaw projection, a smaller brain, paedomorphic behaviour, reduced sexual dimorphism

Question 20

What is central place foraging?

Answer 20

Not seen in any other primate, where food is brought back to share at a central place (must exhibit inhibition to not eat the food beforehand)

Question 21

What is intergenerational food transfer?

Answer 21

Widespread food sharing of hard-to-acquire food

Question 22

How is egalitarianism maintained in some hunter-gatherer societies?

Answer 22

Cooling the heart of the hunter (humbling hunters)

Question 23

What is counter-dominance/reverse dominance?

Answer 23

Lower ranking animals teaming up on an upstart or bully through coordinated action, typically requiring language to coordinate attack

Question 24

Is counter-dominance/reverse dominance possible in baboons/chimpanzees?

Answer 24

No - they cannot coordinate amongst themselves

Question 25

What can counter-dominance/reverse dominance result in?

Answer 25

Sanctions or capital punishment

Question 26

Who tends to be the victims of capital punishment in small-scale societies?

Answer 26

Aggressors and non-cooperators (mostly males)

Question 27

How do hunter-gatherer societies deal with unrelenting bullies?

Answer 27

Capital punishment (which requires approval of the group)

Question 28

What is the mechanisms by which humans have evolved reduced reactive aggression?

Answer 28

Used proactive aggression to combat individual displays of reactive aggression