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Social Learning: Required for Culture

1. Female Choice2. Whale Song

3. Tool Fabrication by Crows

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Social Learning: Required for Culture

1. Female Choice: interaction of cultural evolutionand biological evolution

2. Whale Song: pace of cultural evolution,horizontal transmission

3. New Caledonian Crows: uniqueness of human cultural capacities

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Female Choice: Shoaling Fish

Witte & Noltemeier, 2002. Behav Ecol Sociobiol 52:194.

Sailfin molly (Poecilia latipinna)Mixed-sex groups (20 fish); Live-bearingBackground female choice

Females observe others’ mate choiceSocially acquired mate preference?

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Witte & Noltemeier (2002)

Female mate choice - backgroundGenetic/Intrinsic preference: Large males

Common, especially parenting males

Fish, Birds, Mammals(?)Females – observational (social) learningCopy mate choice of other females

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Witte & Noltemeier (2002)

Mate-choice copying Cultural transmission: impact sexual selection

Learn preferenceRetain, transmit to other femalesCultural transmission within sex

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Witte & Noltemeier (2002)

Horizontally transferred cultural traitaffects female choice (sexual selection)

Might cultural trait oppose (apparent) naturally selected choice behavior?

If so, is cultural evolution more important than biological evolution is some species/traits?

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Witte & Noltemeier (2002)

Aquarium tests: Female observes and then chooses

First preference test: 2 males, differing in size

Second preference testa) Same as firstb) Larger male versus

smaller male with 2 females for10 minc) with 1 female for 20 min

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Witte & Noltemeier (2002)a) No change in pref.

for smaller maleb) Significant

increase in pref. for smaller male, after observe 2 females near male

c) Significant increase in pref. for smaller male, after observe female near male

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Witte & Noltemeier (2002)

Observation of other females reversed subject females’ innate (genetic?) preference from larger to

smaller males

Culturally transmitted mating preference apparently reverses effect of female choice on sexual selection among males

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Whale Song: Rapid Cultural Change

Cultural Evolution3 transmission modes

Cultural diversity and pace

Horizontal Transmission“Epidemic” – faster than vertical

Faster than biological evolution

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Whale Song: Rapid Cultural Change

Noad et al., 2000. Nature 408:537.

Humpback whale (Megaptera novaeangliae)Males sing while migrating, breedingSexual display, male-male &/or attract females

Trait diversity (historically):• Within-population heterogeneity low• Between-population heterogeneity

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Noad et al. (2000)

East, West coast Australia: different populationsVery different songs

1996: 2 males moved dispersed west to eastWithin 2 years: Social mimicry

Cultural change, new song common

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Noad et al. (2000)

“Cultural Revolution”

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Noad et al. (2000)

Whale song: languageRapid cultural evolutionFaster than biological evolutionTimescales

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Tool Manufacture: Cultural Innovation

Distinct Human Cultural Traits1. Tool use

Woodpecker finch, chimps, …

2. Fabrication of toolsNew Caledonian Crow(Corvus moneduloides)

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Tool Manufacture: Cultural Innovation

Hunt & Gray, 2003. Proc Roy Soc Lond B 270:867.

New Caledonian Crow

Tool manufacture, useLeaf modification, foraging“Technological evolution”

via cultural transmission

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Hunt & Gray (2003)

Many animals use tools; prey extractionTool manufacture rare

Technological “evolution” very rare

Humans: technological changeFaithful social transmission of design

Understand function of object(necessary?)

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Hunt & Gray (2003)

Chimps: tool manufacture “haphazard”No evidence of technological evolution

Standard: human stone toolsDiversification, Intention

Suggestion: New Caledonian crowsPandanus leaves, 3 types of foraging tool

Cultural transmission/technology evolved

A New Caledonian crow pair which exclusively selected either pandanus tools (female at left) or stick tools (male at right).

Hunt G R , and Gray R D Biol. Lett. 2007;3:173-175

©2007 by The Royal Society

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Hunt & Gray (2003): 3 types of tool

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Hunt & Gray (2003)

Wide, narrow, stepped forms

Increasing complexity “manufacture”

Vertically transmitted, social learning

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Hunt & Gray (2003): Site fidelity

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Hunt & Gray (2003)

Cultural innovation & technological evolution

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New Caledonian Crow (Melhorn et al. 2010; Brain, Behavior and Evolution 75:63)

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New Caledonian Crow

Avian mesopallium

No direct sensory input (associative function)Allows “innovative and flexible behavior”Important for learning motor actions in sequence

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Hunt & Gray (2003)

First non-human species “cumulative technology” (?)

Crows: recognized social learning capacitytechnological innovation not solely human trait