PSYC2050 WEEK 12

STREPSIRRHINES

• Lemurs and lorises 

• Only primates with a wet nose 

• Live in Madagascar 

HAPLORRHINES

• Tarsiers  

  • Big eyes, live in Asia 

• Monkeys  

  • New World lives in central/south America, long tail used like a limb

  • Old World live in Africa/Asia, baboons etc.  

• Apes 

  • No tail, large brain, rotating shoulder joints 

PRIMATES

• Reliance on vision rather than smell 

  • Loss of the wet, whiskered nose of other mammals and reduced relative size of the olfactory brain 

  • Colour vision (ripe/unripe fruits) 

  • Stereoscopic 3D vision 

• Encephalised 

  • Larger brain relative to body size 

• Five separate digits and fingernails 

• Mainly omnivorous 

HUMANS AS APES 

• Darwin proposed we are descended from African apes 

• Chimpanzees share 99.4% of tested protein-coding DNA base pairs with humans 

• We are more closely related to chimpanzees than chimpanzees are to gorillas 

• But we are not descended from chimpanzees; we merely share a common ancestor 

GREAT APE COUSINS 

Chimpanzees & Gorilla's 

• Live in Africa  

Orangutan 

• Lives in Southeast Asia 

Bonobo 

• Type of chimpanzees 

• More peaceful 

DARWIN'S PROBLEM 

Physical evolution = continuity of anatomy, nervous and vascular systems. 

He could explain this in relation to humans evolution.  

Mental evolution = continuity of mental capacity. 

He struggled to explain this.  

CONTINUING CONTROVERSIES ABOUT GRADATION

• What precisely are the mental powers of other primates? 

• What precisely are uniquely human traits? 

TWO BIASES IN THE LITERATURE

1. Emphasising discontinuity 

• Believing we are just different 

• To justify personal/religious beliefs about humanity's special status 

• To justify human treatment of animals 

2. Emphasising Continuity  

• To show that Darwin was right and humans are part of nature 

• To show that the animal one is working with has a capacity 

FUTURE WORK

Difficulties identifying absence of a mental trait: 

• Absence of evidence vs. evidence of absence 

The importance of making progress can inform us about: 

• The evolution of the human mind 

• The genetic and neurological basis of higher cognitive capacities 

ANIMAL CONSCIOUSNESS 

If an animal has the same neuronal equipment to detect damage as humans and shows the same behaviour as humans, then it likely feels pain much like us  

INTELLIGENCE IN ANIMALS 

George Romanes 

• Used anecdotes to explain animals’ behaviour like human behaviour 

The principle of Parsimony: 

• Simpler explanations for animal behaviour should be preferred until they are ruled out 

CLEVER HANS PHENOMENON

• A horse solved cognitive problems  

• BUT the horse could only solve the problem if the owner knew the answer 

• The horse could only solve the problem if the person asking the question was in his presence 

• THEREFORE, the horse was looking for subtle cues in the owner's face to learn when to stop stomping 

LESSONS FROM COMPARATIVE PSYCHOLOGY  

Using the Clever Hans Phenomenon 

1. Behaviour that seems to involve complex cognitive processing can be produced by much simple mechanisms 

2. Researchers must be careful to avoid introducing cues that could lead an animal to pass a test without understanding 

INTELLIGENT APES?

• Joining two sticks together to make a longer stick to grab food  

• Banana on the roof and boxes in the room, the ape stacks the boxes to reach the banana 

• Use tools in the wild 

• These actions can't  be explained by other learning theories such as trial-and-error, proposing some insight 

MACHIAVELLIAN HYPOTHESIS OF INTELLIGENCE 

Social intelligence as the prime mover of intelligence evolution. 

Evidence:

• The association between neocortex ratio and group size. 

Primate social intelligence:

• Group living  - know who is who 

• Grooming (form bonds and friendships) 

• Social hierarchies (not just based on size and strength) 

• Keep track of third-party relationships (knowing who is related to whom) 

• Tactical deception 

• Cooperation 

• Imitation and imitation recognition 

• culture 

CULTURE IN CHIMPANZEES? 

Nut cracking with stones 

• Some groups use logs 

• Some groups don't do the behaviour  

• Explained by it being socially passed on 

Group meeting 

• High five, hold hand, groom each other 

• Only some groups do 

• Social learning 

COMMUNICATION

Max Mueller 1860/70s 

• No other communication system is open-ended like human language 

Richard Garner 1890s 

• Playback studies with Edison's phonograph to listen to monkeys conversations 

• Became like a joke 

Re-discovery of playback approach 1980s 

• Velvet monkey alarm call types 

  • Leopard, eagle, python, cat, baboon, human 

  • Call wolf? Deception? 

• No evidence of non-human syntactical languages (grammatical rules) 

MIRROR SELF-RECOGNITION 

Gallup 1970, Mark Test 

• A mark is put on their body somewhere they otherwise wouldn’t see 

• They take off mark 

• Shows self-awareness 

• Children typically pass around 18 months 

• Success only in great apes; no small apes passed 

PRETEND PLAY 

Pretence involves primary representation of reality and secondary representation of pretend world.  

• Home-reared great apes play with dolls and treat them 'as if' real 

 

SECONDARY REPRESENTATIONS 

Great apes (chimpanzees, orangutans and gorillas) are the only primates to have provided evidence for: 

• Pretence 

• Insightful problem solving 

• Mirror self-recognition 

• Imitation games 

PHYLOGENETIC RECONSTRUCTION 

Analogy = same function but evolved independently 

Homology = function evolved via common descent  

• One assumption for homology  

• Four assumptions for analogy  

• Secondary representation must have come from a Great ape ancestor around 15 million years ago 

 

THE HOMININS 

A few million years ago, there were over 20 different species of humans, some living at the same time.  

• The gap between humans and chimpanzees appears so large because all hominins have died out (or been displaced by homo sapiens). 

• Therefore we must say chimpanzees are our closest living relatives 

How do we define intelligence in species other than humans? 

We often define animal intelligence in comparison to humans; we compare their actions and behaviours to ours to determine their measure of intelligence.  

Are other animals conscious? Where do we draw the line? 

I believe anything with a brain is a conscious being. It is difficult to know, however, as consciousness is an internal process that cannot be measured. We only know it from our own awareness, so we infer it from whether their nervous systems and behaviours are similar to ours.  

What does it mean to ethically attribute consciousness to animals? 

By attributing consciousness to an animal, we are inferring that they can feel pain, fear or pleasure.  

COGNITIVE CAPACITIES ANIMALS DEMONSTRATE

• The use of tools  

• Imitation 

• Learning (operant and classical) 

• Concepts  

• Abstract thoughts 

• Some language/communication