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L4

Terms in this set (28)

4.1
How we accumulate culture
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Why do humans have so much cumulative culture?
• MECHANISM: _________ fire when observing an action being demonstrated
• ONTOGENY: humans_________ and _________, especially in _________
• FUNCTION: _________ and _________ was necessary to survive in the
_________ ; solution of these problems had to be learned and retained
• PHYLOGENY: we are_________ ; all _________ live in groups and most are
_________ ; _________ primates use more_________ .
• TODAY:
• Mechanisms of cumulative culture, beginning with a comparisons with other
_________ (_________ ).
mirror neurons,
imitate and teach a lot, WEIRD cultures
our cooperative hunting, reproduction, African savannah
haplorhine primate,haplorhines, groups, terrestrial, tools.
HOMINIDS (GREAT APES).
Comparing the Great Apes, including us
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Are humans smarter than other apes?
• FIRST — compare ADULT APES (Chimpanzee, Orangutan) to HUMAN toddlers (2 years old)
• PRIMATE TEST BATTERY:
• PHYSICAL COGNITION
• Space: Locating a reward; locating it after landmarks are rotated or changed
• Quantity: Relative quantity of objects; addition of objects
• Causality: Understanding that a feature change predicted reward; using a tool to retrieve a reward
• SOCIAL COGNITION
• Social learning: using imitation to solve a novel problem
• Communication: understanding others are pointing to reward; gesturing to receive a reward from
others, taking others attentional state into considering when gesturing
• Theory of mind: following gaze of other; understanding that an intention failed
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Humans do not have greater general intelligence
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Culture in the lab... in DUCKS
First ever voc!l le!rning in Anseriformes
— published this week
• Before this week, vocal learning only in
• Parrots
• Hummingbird
• Oscine songbirds
• Now: 1 duck
• Captive male
• Recorded 30 yrs ago
• Dutch biologist tracked down recording, analyzed it carefully, published this week
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In Captivity
- More stimuli,
more time - Male duck;
sexual selection?
Asian elephant - Also captive - Imitated tra"c
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Teaching was only recently observed
1) Teacher modi!es behavior only in presence of Pupil
2) Teaching costly to Teacher, with no immediate return
3) Teacher encourages or punishes or sets example, shaping behavior of Pupil
4) Pupil acquires information more rapidly or at less cost or even at all
FIRST EXAMPLES that met ALL CRITERIA was in.....ANTS
(2005) Tandem running demonstrated in Temnothorax
TEACHER knows where food is; PUPIL follows, touching abdomen
TEACHER stops if PUPIL is lost; TEACHER pays costs, PUPIL bene!ts
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Finally in a mammal (2008)
• Large Groups (20-40)
• Cooperative Breeders
• 1 Pair produces 80% pups; others help to raise
• EAT SCORPIONS
• pups have to learn HOW without being hurt
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Summary
• Human evolution is a product of dual inheritance:
• Genetic evolution in#uences cultural evolution
• Cultural evolution in#uences genetic evolution
• ONTOGENY
• Compared to other apes, human children are better at social learning
• THIS WEEK'S WRITTEN ASSIGNMENT:
• Analyze the paper describing the experiment in the !lm.
• But CULTURAL TRANSMISSION, even teaching, found in diverse species (ducks, ants..)
• Increase motivation (scorpion sting), volume of data (e.g., captivity), social learning may
be surprisingly ubiquitous
• But how is human TEACHING di$erent?
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4.2
How WEIRD humans learn
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Repertoire of cultural transmission strategies
• SOCIAL TOLERANCE: teacher grants learner access for close observation.
• EXAMPLE: Chimp mother allows young to watch closely.
• OPPORTUNITY PROVISIONING: teacher provides access to activities too di"cult or dangerous for
learner to explore independently without modi!cation.
• EXAMPLE: Meerkat facilitates learning of how to eat a scorpion.
• EVALUATIVE FEEDBACK: teacher provides pos or neg feedback by teasing, warning of danger or
commands to stop, to say or to do.
• EXAMPLE: Honeybee stops naive bees from learning new knowledge of dangerous place to forage
• SOCIAL OR LOCAL ENHANCEMENT: teacher directs learner's attention to task at hand
• EXAMPLE: cat brings kitten half-dead mouse. Meerkat adult nudges scorpion towards pup.
• DIRECT ACTIVE TEACHING - HUMAN ONLY
• teacher makes relevant aspects of the task accessible or observable, de!ning the boundaries of what is to
be learned, using DIRECT communication, ABSTRACT communication and demonstration
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Yes, we are even WEIRD about teaching
• SMALL-SCALE SOCIETIES (also true in Amazonia, Hadza, etc.)
• POLYNESIAN CULTURES (1000 islands in South Paci!c, New Zealand is the largest)
• FIJI
• DIRECT ACTIVE TEACHING is rare
• what is most common is SOCIAL TOLERANCE
• VANUATU
• VERBAL instruction is uncommon; use gesture, physical contact to instruct
• CULTURAL BELIEFS
• Assume children learn FIRST through observation
• Assume ALL children will contribute work at younger ages (farming, child care)
• HOWEVER - universally - complex and abstract skills are transmitted VERBALLY
Leg!re, C. H. (2017). Cumul!tive cultur!l le!rning: Development !nd diversity. PNAS
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Social Learning in WEIRD cultures
• VERBAL SCAFFOLDING BY ADULTS
• Ask children questions
• Encourage planning
• Provide high levels of praise and encouragement
• Use verbal instruction and repetition to introduce new objects, unfamiliar tasks
• High levels of visual contact (i.e., joint attention)
• These are not human UNIVERSALS, these are ADAPTATIONS in a speci!c
culture — but does it come with costs?
Leg!re, C. H. (2017). Cumul!tive cultur!l le!rning: Development !nd diversity. PNAS
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How we accumluate cumulative culture
• Humans are specialized to be HIGHLY ATTENTIVE to social cues
• Yet there are cultural di$erences
• WEIRD emphasizes DIRECT ACTIVE TEACHING much more than others, where
the child is expected to observe and learn for themselves
• How this changes cognition is being now studied by a new generation of crosscultural
cognitive scientists (more on this later)
• But in all societies, the more ABSTRACT the problem, the more ACTIVE TEACHING
using LANGUAGE is necessary.
• This can be studied in the lab using
• ARTIFICIAL cultures
• ARTIFICIAL languages
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4.3
Studying culture in the lab
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How to make a culture
• 100 undergraduates (WEIRD, yes)
• Two treatments, 10 generations:
• 1 model: only one "cultural parent"
• 5: all 5 cultural parents
• Incentive: ra%e tickets for $100 prize won if they
performed best in their own generation OR their
"cultural o$spring" did
• PROBLEM to solve:
• Expt 1: Learn program to recreate target image
• Had 15 minutes to write TWO PAGES of
instructions
• Next learner: got all instructions from previous
generation; had 25 minutes
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Large group transmitted more effectively
• Only 5-model group
improved over
generations
• After 10th Generation:
• LEAST skilled 5-model >
MOST skilled 1-model
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Begin with experts
Experiment 2
• Made video (headcam) of process
• Had 25 minutes to learn from videos
• RESULTS
• 5-Model learners maintained accuracy
• 1-Model
• Even learning from expert, steep loss
of knowledge
• SIGNIFICANCE
• EXPERT learning lost rapidly with
only one expert to observe
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Summary
• Humans have mechanisms to CREATE and SUSTAIN cumulative culture
• SOCIAL LEARNING biases
• IMITATION biases
• MANY forms of TEACHING
• LIVE in social groups with many potential teachers
• MORE TEACHERS, more accurate transmission of skills
• Next week: from cultural evolution to genetic evolution
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4.4
How we lose culture
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Culture can be lost
• INUIT: Northernmost human population
• Advanced cumulative culture
• 1820's: epidemic; OLDEST HUNTERS DIED
• Without written language, lost repository of knowledge
• TOOLS lost, POPULATION SIZE decline
• NO Leisters = No Arctic char (!sh)
• NO Bow and arrow = No caribou hunting
• LOST TECHNOLOGY for snow house entrance
• LOST TECHNOLOGY for KAYAK
• No contact with other tribes to re-learn technology
• 1862: contacted by exploring BAFFIN ISLAND group, in kayaks
• Re-learned technology, using Ba"n design for kayak
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Tasmanian cultural history
• 34k years ago
• Paleolithic settlers came from AUSTRALIA mainland over land bridge
• 12k years ago
• Isolated by Glaciers for 12,000 years
• Late 18thC: Europeans arrived and described culture
• WORLD'S SIMPLEST TOOLKIT: only 24 items
• BOAT: only a ra! without paddles
• WEAPONS: rocks, clubs
• NO FIRE
• NO CONTAINERS (drank from skulls)
• NO BONE TOOLS
• NO COLD weather clothing
• Did not eat FISH (and refused it)
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Tasmania vs Mainland Toolkits
• Australian population in Victoria at the same time
• 200 miles across the strait
• Hundreds of tools
• bowls, sewn-bark canoes
• Fish hooks, nets, !shing spears
• Warm weather clothing (sewn with bone needles)
• Tasmanian: had simpler toolkit than had existed since Paleolithic
• Stone points for spears: since 500K
• Hafted tools: since 200K
• Bone harpoon points: since 89K
• Arctic expansion (clothes, boats): since 45K
• Indonesian shark and tuna hunting: since 42K
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What happened in Tasmania?
• 34K: Colonized island via land bridge
• 12K: Bridge submerged by ocean. Toolkit was equivalent to mainland at this point.
• 5K: Were still eating !sh (archeological evidence from middens)
• 3.5K: Loss of bone tools and !sh bones in archeological record
• When Europeans arrived (1777)
• Would not accept !sh as food, though accepted other foods from Europeans
• No bone needles, no sewn clothing; wore whole skin, grease on skin
• On the mainland: 200 miles away: LARGE, CONTIGUOUS POPULATIONS
• New tools, social institutions, rituals continued to emerge
• Tasmania: continued to LOSE cumulative culture because of small COLLECTIVE BRAIN.
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On the Mainland
• Pama-Nyungan expansion
• Emerged 3-5K in NW
• Distinctive tool (backed blade)
• New plant foods
• New seed processing
• Seed storage
• Trade networks
• Expanded over continent
• Did not cross Bass Strait
• Tasmanians continued to lose technology
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The size of the collective brain matters
• Population size and tool
accumulation?
• Isolated Islands
• Independent measure of
tool evolution
• Result: population size
correlated with tool diversity
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Summary: Our Collective Brains
• Many species have collective brains: depend on group knowledge to survive
• Vocal imitation, Teaching
• But humans are wired to absorb that knowledge faster and more accurately
• Our super power is social learning
• This can be seen in the lab: the importance of learning from a group
• Smaller groups accumulate errors, lose the skill
• This can be seen in history:
• Loss of skills in Arctic, in Tasmania
• Larger groups retain more tools, more skills
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