Lecture: Social Cognitive Science and the Evolution of Intelligence

Question 1

What we know of our ancestor’s bodies come from

fossils, but what are the 2 problems associated with this?

Answer 1

1) Behaviour is not fossilized (Thus, we rely on scant artifacts but even those appear relatively recently)
2) Fossils are very rare (It is thought that one bone in a billion becomes fossilized. That means that for the population of Canada at 34 million, six of the human bones around today will end up getting fossilized [That’s bones, not skeletons.] And that not even to say that they’d ever be found. Human fossils are very rare.)

Question 2

How long have humans been around?

Answer 2

• The oldest fossils of fully-formed humans are only 50k-100k years old. That’s only 2500-5000 generation of 20 years
• If language is an instinct, like Chomsky says it is, then it probably had to have been evolving for longer than humans have been around. Ancestors are people who have reproduced.
• Australopithecines had hands evolved for manipulation. We don’t know that they didn’t use tools.
• However, only stone & metal tools last, most modern hunter-gatherer societies of today have more biodegradable tools than stone ones.

Question 3

what is the standard timetable for human evolution?

Answer 3

• We differentiated from something 100l-200k years ago

- We differentiated from chimps much longer ago (most recent branch, we split off from)

Question 4

How do we know the standard timetable for human evolution?

Answer 4

• We know this because a mitochondrial eve (ancestor of all humans- can’t do this for fathers), which is the most distantly historical female that is the ancestor of all living humans.
• She need not be human herself
• Mitochondria are weird- they have their own DNA. They were probably a parasite (they were the inspiration for the midichlorians in star wars)

Question 5

From the video shown in class, what is the proof of human evolution we can find on our own body?

Answer 5

• Movement of ears
• Goosebumps
• Vestigial muscle

Question 6

What unusual findings were discovered in Zaire?

Answer 6

• The oldest human fossils were found in Africa, form about 100,000 years ago.
• However, some stuff found in Zaire has modernish looking tools but they were dated 75k years ago.
• This is like finding a car in da vinci’s attic

Question 7

Why are fossils so rare/hard to find?

Answer 7

• Most living things leave no record at all
• It is estimated that 1 in 10 thousand species ever gets fossilized
• Most creatures don’t die in sediment
• 95% of fossils are from marine creatures in shallow parts of the water

Question 8

What animal do we share 70% of our genes with?

Answer 8

Keep in mind we share 70% of our DNA

with mice.

Question 9

What is Pinker’s vision theory for why people got so smart?

Answer 9

• Relying on vision is so important because it is inherently 3D, unlike olfaction
• Olfactory animals, such as dogs, keep their heads close to the ground much of the time
• “It’s a two-dimensional flatland viewed through a one-dimensional peephole”
• 3D thinking requires more brain power

Question 10

What is the group living theory for why people got so smart?

Answer 10

• Dunbar’s paper that you read
• Human lives differ from other primates mostly in terms of their social environments
• We evolved smart brains to: Communicate important information, Keep track of everyone else and maintain social relationships (requires larger brain power), Results in a social cognition arms race (humans who were good at this out reproduced everyone else).

Question 11

What is the hunting theory (ecological hypothesis) for why people got so smart?

Answer 11

• In general, carnivores are more intelligent than herbivores’
• It takes more brains to hunt a rabbit than for a rabbit to hunt a lettuce head. Mental map size.
• Meat is nutritious. Relying on meat allowed brains to trust that nutrition will be in the environment, allowing brains to grow bigger
• Big kills encourage socialization/ group cohesion
• Meat from a wild bull can feed 1000 people. Make a deal with your neighbours, so they’ll share with you when they get lucky.

Question 12

What is the Hand/Walking upright theory for why people got so smart?

Answer 12

• Walking upright allowed us to exapt our hands for different functions, which could make good use of more intelligence
• Hands allow us to carry things, which allows us to create complex objects with parts from different geographical areas
• Requires planning, imagination, working memory
• These things work in a positive feedback loop
• However, there is no evidence of artifacts from the million and a half first years of bipedality
• There are 12 theories of why humans became bipedal

Question 13

More about the upright position

Answer 13

• Upright posture puts pressure on pelvis to be small, but brains are big. This is dangerous for women giving birth. And this is why babies are altricious (useless). Evolution made the pelvis break apart during birth and the baby’s head soft and delicate so it can squish through the birth canal.
• To maintain the intelligence arms race, evolution discovered a different strategy of altriciousness
• Altriciousness means more infant care by parents
• More infant care mean more male attention and pair-bonding