Chapter 12. Primate Intelligence

Why Are Primate Brains Large?

• More Expensive Tissue

• Influences Life History Traits

• Adaptive

What Is Correlated With Big Brains?

Longevity.

Where Do Primates Allocate Their Energy In The Life History Theory?

• Growth

• Maintenance

• Reproduction

What Are The Trade Off’s Of The Life History Theory?

• Growing And Maintaining Self/Offspring

• Quantity vs. Quality Of Offspring

• Current & Future Reproduction

What Are The Traits Of A Fast Life History (R Selected)

• Reproduce Early

• Small Brain/Body

• Short Gestation, Large Litters

• High Mortality Rate, Shorter Life Span

What Are The Traits Of A Slow Life History (R Selected)

• Reproduce Late

• Large Brain/Body

• Long Gestation, Small Litters

• Low Mortality Rate, Longer Life Span

Do All Primates have the Same Length Of Life Histories?

No. Apes Have Slower Life Histories Than Monkey’s.

What Are 2 Selective Pressures That Favour A Large Brain Size?

1. Social Factors

2. Ecological Factors

What Are The Selective Pressures of Social Factors That Favour Bigger Brains?

• Competition Pressures In A Group

• Bigger Groups Make Social Life Complex

• Behavioural Flexibility Becoming More Useful

What Are The Selective Pressures of Ecological Factors That Favour Bigger Brains?

• Skills Through Frugivory

• Extrication Of Foods

• Learning/Behavioural Traits

• Behavioural Flexibility Hypothesis

Social Intelligence Hypothesis

Species Living In Large Groups Are More Intelligent

Behavioural Flexibility Hypothesis

Frugivores More Intelligent Than Folivores, Extractive Foragers More intelligent Than Others.

3 Portions Of Brain

• Hindbrain

• Midbrain

• Forebrain

Hindbrain

• Cerebellum, Pons, Medulla

• Controls Basic Functions (Breathing, Coordination)

Midbrain

• Controls Sensory Input

Forebrain

• Cerebrum (Hemispheres, Lobes)

• Controls Higher Cognitive Functions

Neocortex Ratio

• Neocortex Volume (Forebrain) to Volume Of The Rest Of The Brain Ratio (e.g. 60:1)

• Used To Measure Cognitive Complexity

What Do NHP Know?

• 3rd Party Kinship

• Dominance Hierarchies

Vervet Monkey Playback Experiments

• Experiment A:

  • Played Distressed Calls From Younger Monkeys, Mothers Responded

• Experiment B:

  • Threatened Monkeys Redirect Aggression To Lower-Ranking Monkeys

Baboon Playback Experiments

• Recorded Different Hierarchical Grunts & Barks, Played In Unexpected Order

• Baboons Confused

What Do NHP Know About The State-Of-Mind Of Others?

• Can predict Others Will Do, Modify Behaviour Accordingly

Theory Of Mind

• Attribute & Understand Mental States Of Others

• Bigger Than General Intelligence

Theory of Mind In The Wild

• Chimp Prevented With Fake Snake

  • Alarm Call Others Who Hadn’t Seen Snake Or Heard Calls

Theory Of Mind Experiments 1/2

• Take Food From Competitor Whose Face Is Turned Away From Them/Food

Theory Of Mind Experiments 3

• Choose Food From Box Without Bell (Silent)