Human Overview Flashcards
What are human traits that are unique compared to other primates?
1) Bipedalism
2) Aerobic endurance capacity
3) Bigger brains
4) More hypercooperative/prosocial and less aggressive
What is aggression?
An adaptive strategy among most primates to increase reproductive success
Who were the first hominins?
1) Ardipithecus ramidus (4.4 mya)
2) Australopithecus afarensis (LUCY) (3.5 mya)
Describe the characteristics of Ardipithecus ramidus
1) Bipedal in the trees and on the ground (divergent hallux)
2) Chimpanzee-sized brain
Describe the characteristics of Australopithecus afarensis (LUCY)?
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
What is shared intentionality?
1) Ability and motivation to engage with others in collaborative, cooperative activities with joint goals and intention
2) The source of all cognitive achievements
What does Rousseau say about human nature?
Humans are naturally cooperative and unaggressive, where aggression only arose with civilization
What does Hobbes say about human nature?
Humans are naturally competitive and violent, where stronger governments are required to tame human instincts
What are the 2 types of aggression?
1) Reactive
2) Proactive
What is reactive aggression?
Sudden (often in response to fear or contest), where the target can easily be switched
What is proactive aggression?
Pre-planned according to desire, with a fixed target
What happened during human evolution in terms of aggression?
Reactive aggression has been reduced and proactive aggression is more prominent
What did Hill and Hurtado observe with the Ache (hunter-gatherer) foragers?
In the 17 years they were there, they never observed a scuffle between Ache men
What is the rate of male “scuffles” in human males vs chimpanzees?
Human males “scuffle” at ~1/1000th of the chimpanzee rate
What is self-domestication?
Evolution of a reduced propensity for reactive aggression (compared to an immediate ancestor) without the active involvement of another species
What is the domestication syndrome?
Domesticated animals tend to look a particular way, even though those phenotypic traits are not directly selected for (pleiotropy)
What may indirectly occur when we select for reduced aggression, fear, and stress response in animals?
1) Reduced brain size
2) Reduced muzzles, smaller teeth
3) White patches
For bonobos, where reduced aggression has been selected for, what are the associated unselected traits?
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
What is the anatomical evidence to suggest that humans were self-domesticated?
AMH have smaller teeth, a flatter bow ridge, more circular crania, reduced jaw projection, a smaller brain, paedomorphic behaviour, reduced sexual dimorphism
What is central place foraging?
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)
What is intergenerational food transfer?
Widespread food sharing of hard-to-acquire food
How is egalitarianism maintained in some hunter-gatherer societies?
Cooling the heart of the hunter (humbling hunters)
What is counter-dominance/reverse dominance?
Lower ranking animals teaming up on an upstart or bully through coordinated action, typically requiring language to coordinate attack
Is counter-dominance/reverse dominance possible in baboons/chimpanzees?
No - they cannot coordinate amongst themselves
