Philosophy
Raciel1990
CULTPSY3_Ch02_HumanNature-1.pptx
Lecture PowerPoint Slides
By
Benjamin Cheung
Chapter 2—Culture and Human Nature
© 2016 by W. W. Norton & Company
Cultural Psychology
Third Edition
Steven J. Heine
Chapter Objectives
In this chapter, you will:
Discuss evidence of culture in different members of the animal kingdom
Understand how prestige bias facilitates cultural learning among humans
Differentiate between imitative learning vs. emulative learning
Describe the role of theory of mind in cultural learning among humans
Understand how language allows for cultural learning, and for it to be cumulative
Define the ratchet effect
Explain the ratchet effect in the context of cumulative cultural learning
Generate examples of the ratchet effect
© 2016 by W. W. Norton & Company
Chapter Objectives
In this chapter, you will:
Discuss how group size (large and small) affects cumulative cultural learning
Discuss the role of brain evolution in cultural learning
Understand the costs and benefits of larger brains
Critique the major theories that explain how primates’ brains grew large
Discuss the benefits that human brains have over other primate brains in terms of cultural learning
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Overriding Themes in This Chapter
What separates us from other ape species despite sharing common ancestors?
What separates us from other animals?
How did we become a cultural species over the course of evolution?
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Humans vs. Other Ape Species
1940s–1970s: Noell’s Ark Gorilla Show
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No humans could win in a fight against an ape species.
Other ape species are much brawnier than humans.
But they shared common ancestors with humans 5 to 7 million years ago.
How did we lose the muscle mass, and what did we gain in exchange?
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Is Culture Unique to Humans?
Depends on definition of “culture”
Specific/concrete: Culture = “having symbolic meaning”
Then culture is unique to humans
Abstract definition: Culture = “learning through social transmission”
Then culture is not unique to humans
Preferred definition for this textbook
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Cultural Learning in Other Species
Different cultures of chimpanzees have formed.
Twig-fishers vs. bark-fishers
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Cultural Learning in Other Species
Elephants developed a culture of aggression over generations in response to hunting.
Killer whales in different regions speak different dialects.
Many other species show the capacity to have “culture.”
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Human Cultural Learning
Humans are not unique in engaging in cultural learning.
But unique in extent of this learning
Two key characteristics of human cultural learning that make it unique:
Speed
Use of “prestige” cues
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Human Cultural Learning—Speed
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Human cultural learning tends to be quicker than in other species
Animal cultural learning can take many years.
Human cultural learning can take a single exposure.
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Humans are attuned to cues that signal prestige on the part of the model.
A general learning mechanism engages to copy everything the prestigious model does.
Human Cultural Learning— Prestige
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Humans are attuned to cues that signal prestige, such as the huge number of adoring fans surrounding the model.
We use these prestige cues as heuristics to determine whom to learn from and copy.
A general learning mechanism engages to copy everything the prestigious model does because we don’t know what makes that model so prestigious–shoes? Equipment? Facial hair? Active lifestyle?
Copying everything maximizes the chances of learning successfully.
Possibly leads to transmission of irrelevant/inefficient behaviors.
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Human Cultural Learning
Humans also have unique cognitive abilities that set human cultural learning apart from other animals.
Two key cognitive abilities:
Theory of Mind (ToM)
Language
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Human Cultural Learning—ToM
Theory of Mind (ToM) = understand that others have minds, intentions, and perspectives different from one’s own
This ability is found in humans, not in most other species.
Mixed ToM results with chimpanzees.
Those trained by humans show some signs of ToM.
Those existing in the wild do not show ToM.
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Advantage of ToM—Imitation vs. Emulation
Humans and chimpanzees learn through two different forms of learning
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Types of learning
Imitative learning
Emulative learning
Internalizes models’ goals and behavioral strategies
Learners over-imitate models
Focus on fulfilling goal of the model
Requires ToM
Learner, alone, tries to figure out how an object affects environment
Focus on how to manipulate an object to change the environment
Does not require ToM
Imitative learning = learner internalizes goals and behavioral strategies of the model.
Learners overimitate models by copying everything a model does.
Focus is on figuring out how to fulfill the goal of the model.
Requires ToM
Used by humans
Emulative learning = learner tries to figure out individually how an object can affect the environment.
Focus is on how to manipulate an object to change the environment.
Does not require ToM
Used by chimpanzees and other primates
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Imitative vs. Emulative Learning
Nagel et al. (1993): 2-year-old children and chimpanzees shown a model retrieving an object using a rake in one of two ways:
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Less effective
More effective
“Teeth down” is less effective: object can slip through teeth.
“Teeth up” is much more effective.
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Imitative vs. Emulative Learning
Results:
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Imitative learning
Whatever model did
Emulative learning
Results:
Applying emulative learning, chimpanzees independently figured out the more effective method of using the rake.
All used the rake “teeth up,” regardless of what the model did.
Applying imitative learning, children copied whatever the model did.
Thus, emulative learning can be a very effective and intelligent kind of learning.
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Which Type of Learning Is Better?
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Types of learning
Imitative learning
Emulative learning
Less efficient: leads one to copy irrelevant behaviors
Requires models to exist
But allows for faithful and high-fidelity reproduction of target behavior
Allows for cumulative cultural learning*
More efficient: learner can directly figure out effective ways of using a tool
Does not allow for cumulative cultural learning*
*We will return to this later
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Language allows humans to clearly communicate ideas, especially complicated ones.
Human language is unique in having a complex grammar and syntax, as well as a rich vocabulary.
It is necessary for successful and precise transmission of cultural ideas.
Allows for cumulative cultural learning
Language Facilitates Cultural Learning
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Language allows humans to clearly communicate ideas, especially complicated ones.
Human language is unique in having a complex grammar and syntax, as well as a rich vocabulary.
It is necessary for successful and precise transmission of cultural ideas.
Allows for cumulative cultural learning
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What Is Cumulative Culture?
Major differentiation between human and other animal cultures
Characterized by the ratchet effect
Over time, other people gradually make modifications and improvements to some original tools/ideas
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What Is Cumulative Culture?
Requires reliable and faithful social transmission
Requires imitative learning and sophisticated language
Individual learning through emulative learning does not allow for a ratchet effect across generations.
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Example of Cumulative Culture
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Throughout evolutionary history, the “hammer” has ratcheted up from simple stones to the hammer we know today.
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Questions for Consideration
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Discuss: Other than tools, what else can we consider to be cumulative cultural innovations?
What allows humans, biologically, to have the traits and cognitive abilities to facilitate cumulative cultural learning?
Tools are not the only “cultural ideas” to result from cumulative cultural innovations. What else can we also consider to be cumulative cultural innovations?
What allows humans, biologically, to have the traits and cognitive abilities to facilitate cumulative cultural learning?
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The Human Brain
Human brain has large encephalization quotient (EQ)
Human EQ ≈ 4.6
4.6 times larger than would be expected given our size!
Allows us to have the cognitive resources for the complex mental capabilities for cumulative cultural learning…but at a cost
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Brain weight of animal
EQ =
Predicted brain weight compared to animals of same size
Costs of Human Brain
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2% of body weight
16% of all basal metabolism
*Brains of other animals use 1 to 3% of basal metabolism*
Such a large brain has an immense energetic cost.
Energy hog the human brain consumes 16% of all basal metabolism.
The brain only accounts for 2% of body weight.
In comparison: in many other animals, their brains use 1 to 3% of basal metabolism.
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Human EQ almost twice that of chimpanzees, our closest genetic relatives
Bodies needed to change to accommodate increased energetic demands of larger brains
Loss of muscle mass
Smaller digestive tract (aided by invention of cooking)
What We Gave Up for Brain Power
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Why So Large?
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Must have been evolutionarily advantageous for brains to be so large
Three propositions:
Fruit consumption
Food extraction
Social brain
Presumably, success for these three propositions requires larger brains.
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Fruit Consumption
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Many primates eat a lot of fruit in their diet, but fruits are seasonal and grow in patches
Fruited-based diet requires mental maps of such fruit patches for successful foraging.
Primates more adept at keeping such mental maps were more able to provide for offspring.
Food extraction
Some primates eat food that require ingenuity to extract (e.g. nuts, seeds).
Smarter ones were more adept at extracting food, providing more nutrition to offspring.
© 2016 by W. W. Norton & Company
Social Brain Hypothesis
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Complexity of primates’ social worlds led to a need for successful navigation of complex relationships.
More socially adept primates attracted more mates, accrued more resources, and protected offspring better.
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Which Is Empirically Supported?
Using neocortex ratio, Dunbar (1992) examined merits of each proposition
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Volume of neocortex
Neocortex ratio =
Volume of brain
The percentage of fruits in diet and food extraction are unrelated to the neocortex ratio.
Primates in larger groups tended to have a larger neocortex ratio.
Primate brain evolution was largely driven by a highly social lifestyle.
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Magic Number 150
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Based on human neocortex ratio, human ancestral population should be about 150.
This suggests that humans have cognitive capacity to effectively keep track of approximately 150 relations.
Dunbar (1996) found most clans and small communities have an average size of 150.
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Humans Are Especially Social
Humans:
live in larger groups than other primates
appear more interested in each other’s activities than do other primates
engage in more cultural learning than do other primates
Human brains may thus have developed greater social learning and communication abilities than other ape species
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Humans Are Especially Social
Herrmann et al. (2007) contrasted the learning abilities of three primates:
Involved physical and social problem-solving skills
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2.5-year-old human children
Chimpanzees
Orangutans
Some tasks involved general problem-solving skills about the physical world.
Some tasks involved social learning.
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Humans Are Especially Social
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2.5-year-olds are as adept as chimpanzees and orangutans in manipulating a physical environment to solve problems.
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Humans Are Especially Social
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But 2.5-year-olds are better at using social learning to solve problems.
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Humans Are Especially Social
Humans are distinctive in that they engage in so much social learning.
Being able to learn skills from observing others is a key reason behind the evolution of our big brains.
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Summary
Culture is not unique to humans but cumulative cultural learning is.
Cumulative cultural learning is facilitated, and allowed for, by theory of mind, language, and imitative learning.
The evolution of the human brain occurred in connection with social pressures.
We are especially adept, compared to other primates, in realms such as social learning and cultural transmission.
© 2016 by W. W. Norton & Company
