Memes & Changing language

FOA © [email protected] Jan 03CogSci 1

Memes & Changing language

Richard K. Belew• Computational analyses of cultural artifacts• Computational models of evolution, learning


Marta Kutas’ poem

•

repeat again and againdate, mate & procreateor merely carve it on a slateengrave itpaint it on cave wall or a plateor anywhere at allimpress it on any medium via any pressmechanical or electricalor some other -icalnot yet designedand release the ideafrom your mindand create for it a new fate.Imitate and pass it onidentical,similaror slightly modified.Then it's been codifiedand will survive.Perhaps far longerthan any genenow alive.

ImitateCopysmooth or choppyneat or a little sloppyreproduceduplicaterepeat in principle, mimememe - a cultural geneplaying the evolutionary gamewith similar toolswith similar rulesand much the same aimreplicateduplicate


Summary• Key terms

• Replication rate• Fitness• Mutation• Intention• Temporal/spatial distribution• Neutral drift


Summary (cont)• Evolution is a powerful adaptive process• Cultures certainly change• Do “selectionist” models offer the best accounts?• Vast amounts of new evidence becoming

available• The interactions between culture and biological

evolution will only increase in the future


Evolution

• Charles Darwin (1809 -1882)• Definitions• Basic algorithm• GA at a glance


Charles Darwin (1809 -1882)

• Replication• Mutation• Selection


Definitions

• Individual xi = (0,1)L ; string of L bits• Population X = xi ; |X| = P, size of

population• Generation Xt ; population at a point

in time


Basic algorithmCreate X0, randomlydo ; “Generation”

forall xi in XEvaluate fitness f(xi) in R

Determine num. offspring g(xi) in J ; ∑ g(xi) = PForm Xt+1 = g(xi) copies of xiApply genetic operators Ω to Xt+1

until Xt+1 has converged ; (X ≈ Xt+1)


GA at a glance

101010111010100010010111010100101001001011011011010101010101001001001011011110110101010101101011010101101010010101010110

0.2560.6730.3540.5430.4290.8670.2170.3160.6320.5640.5360.5650.4560.9310.101

<f(x)>=0.496

011112012111030

101010001001011101010010100100101101101111011011010100100100101101001011011110110101010101101011101001011010010110100101

101010001001011101010010100100101101001111011011010100100110101101001011011110110101010101100111101010011010010110100101

Mutation

Crossover

Xt Xt+1f(x) g(x)


Evolution, Development,Learning, Culture

• Adaptation as sine qua non of cognitive system

• Adaptation to invariants of environmentat varying time-scales

• Cultural change• Evolution as primary adaptive system• Interaction among adaptive mechanisms• Abstract model• Computational modeling - benefits


Adaptation as sine qua non of cognitive system

What is invariant in adaptive systems will depend on the timeintervals during which we observe them. There are at leastthree time scales of relevance to such systems,corresponding to three different forms of adaptation. - On the shortest time scale intelligent --- hence adaptive ---systems continually change their behavior in the course ofsolving each problem situation they encounter.... - On a somewhat longer time scale, intelligent systemsmake adaptations that are preserved and remain available formeeting new situations successfully.... - On the longest time scale, intelligent systems evolve.

“Cognitive Science: The newest science of the artificial”H. Simon, 1980


Adaptation to invariants of environmentat varying time-scales

Environmentalvariation


Cultural change

• Slower than individuals can change• But faster than evolution can adapt

Environmentalvariation


Evolution as primary adaptivesystem

• Chronologically• (The?) defining characteristic of living systems• Emergence of subsequent adaptive mechanisms

• Ontogenesis• Learning• Culture


Interaction among adaptivemechanisms

• Only models subsuming multiple adaptivemechanisms can speak to interactions amongthem

• But the constituent models (eg, of evolution,learning, etc.) will necessarily be simplified

• Confusions abound• “Inheritance of acquired characteristics” [Lamarck]• “Ontogeny recapitulates phylogeny” [Haeckel]• “Nature” XOR “nurture”?• “Nativist” XOR “empiricist”?• “Race predicts IQ”


Abstract modelL(ph)

L

gM

g'g"

f( ph)...

L

L

d(g)

ph Ph

G$ d-1(g) ?


Computational modeling -benefits

• Algorithmically precise characterization oftheories

• More expressive than other mathematicallanguages (eg, FOPL)

• Models provide insight into statisticalobservations- Mechanistic account underlying variables’

interactions


Computational modeling -benefits (cont)

• Models as interdisciplinary communicationdevices- Composition of sub-models developed by

domain experts


Computational modeling -issues

• Appropriate level of abstraction?• Traditional models

• Veridical relation between features of model andobservables

• Minimal models• Simplest demonstration of phenonmenom• Eg, culture = non-genetic inheritance [Boyd & Richerson]• Eg, learning = multiple guesses [Hinton & Nowlan]


Computational modeling -issues (cont)

• Video games• Demonstration of expressive adequacy• Eg, SimLife

• NB: GA typically used as engineers’ optimizationtechnique• But appears adaptationist in biological context


Memes: Cultural analog of gene• “Replicator in the soup of human culture, ... unit

of cultural transmission, of imitation”• Dawkins’76, Chap11 (revised 1989)

• D. Campbell (1974): Evolutionary Epistemology• Other biologically inspired models of culture

• Cavalli-Sforza & Feldman (1981)• Boyd & Richerson (1985)


Experimental Memetics

• Experiment(22 jan 03)

• Algorithm


Algorithm1. Divide your piece in half2. Optional: Add ‘graffiti’• If you do, add the SAME graffiti to all instances on half• You can add different notes to the two halves3. Pass your two halves to two neighbors• Odd: Front/Back• Even: Left/Right4. SELECT: your favorite ONE from the TWOsheets passed you• (Wad up the other; we’ll collect)Go to #1


Evolution of symbols

• A Brief History• Ancient history ...• ... which ‘evolved’ to exploit a coincidental

mneumonic• ... which becomes a modern bumper sticker!• Perhaps an entire species of bumper stickers!• Survey data T. Lessl]


A Brief History

The fish symbol has been used throughout history by pagan andearth-based religions. Ancient Goddesses in China, Egypt andIndia were represented by the fish symbol. In ancient Greece thefish symbol represented the Goddess of Love. Venus, the ancientRoman empire's Goddess of Love was also represented by a fishsymbol. She was so revered that Christian authorities insisted ontaking over the symbol. The Christians revised the symbol'sassociated mythology to fit their own purposes. Today, the fishsymbol has "evolved" yet again to represent Evolution, Scienceand Political Freedom; as well as all of the topics on our emblemspage.

• According to EvolveFish.com!


Ancient history ...JesusChristGod’sSonSavior------Fish

• In the beginning there was Christian grafftti


... which ‘evolved’ to exploit acoincidental mneumonic

•


... which becomes a modernbumper sticker!

•


Perhaps an entire species ofbumper stickers!

• http://www.evolvefish.com/fish/emblems.html

DARW IN

Jesus lives!

DARW IN Jesus!


Survey data T. Lessl]

• Survey• Lessl’s interpreation


Survey• 140 cars with “fish with legs” DarwinFish on

their bumpers given surveys• “[Lessl] considered using a survey on the Internet, but there is

no way to be sure respondents actually have the fish on theircars. So he set out on foot in parking lots in several states,looking for the symbols and leaving questionnaires underwindshield wipers. He asked three simple questions:”• Why did you put this emblem on your car?• What does the Darwin fish mean to you?• What audience did you hope to reach?

• 51 surveys returned• 66% self-identified as Christian


Lessl’s interpreation "By inserting Darwin's name in to the place on the fish iconusually reserved for Christ, the Icthus symbol is rituallyprofaned," said Lessl, "which is to say, emptied of its religiousmeaning. By putting Darwin's name where Christ's wouldtraditionally go, the Darwin fish does not assert, as one mightthink, that science is salvation and that Darwin is its prophet. Forthe majority of those who display this emblem, Darwin's roleseems to be that of anti-Messiah. This is more like theinversion rituals of carnival, where some drunken peasant isdressed up as the king. Its purpose is not to elevate the peasantbut to make fun of the king."

•


Dawkins’ data!• “If the meme is a

scientific idea... a roughmeasure of its survivalvalue could be obtainedby [its citation count]” -1976

• 1989 notes, citations to[Hamilton’64] used asevidence ofEXPONENTIAL growth

• In distinction to simplyCUMULATIVE citationrates, ala influentialother influential texts


Dan Dennett • What kind of biological analogy?

• Virus?• Symbiotic host/guest

• Parasite: negative effect on host• Commensal: neutral• Mutual: positive

• “Genes hold culture on a leash” [E. O. Wilson]


Dan Dennett (cont)• Intentional stance (on cultural analysis)

• “analyzing the flux of events in terms of agentsand their (rational) actions and reactions”

• “a meme is an information packet with anattitude”

• Intention + biology = genetic engineering! [P.Kitcher, Lives to Come]


A literature-based model ofscientific change

• Science needs to be published• Theories are expressed as arguments• In terms of shared “keywords”• Published record• Available evidence• Lexical dynamics• Temporal feature selection for text categorization


Published record

• Proceedings• Journals• Dissertations• Web


Available evidence

• Text• Authorship• Citation patterns• Meta-data


•

Temporal keyword patternsAIT

AIList

CommDis


Rising/fallingbigrams •


AIList

• Noise(from poorparsing)


CommDis

• “Politicalcorrectness”?


DynamicIDFWeighting

• Up-weighting“seminal”

• “Historicalreview”


Towards “tacit” language

• Use ofARTIFICIALINTELLIGENCEwithin AIT


•

... in SIGIR proceedings


SIGIR corpus• Assoc Computing Machinery • Special Interest Group for Information Retrieval

0102030405060708090

10019

8719

8819

8919

9019

9119

9219

9319

9419

9519

9619

9719

9819

9920

0020

0120

02

No. d

ocum

ents

1987 2002


Replicated on other corpora

Bothconferenceproceedingsand journals


Text classification

•Classifier

0.28 Sports

0.06 Weather

0.17 Business0.34 Entertainment0.11 Politics

Classifier

0.48 Sports0.03 Weather

0.12 Business0.27 Entertainment

0.06 Politics

Summer 1984

…word57

los angelesword59

…

…word57

los angelesword59

…


ACM’s classification of SIGIR Category NDocE. Data 9F. Theory Of Computation 8G. Mathematics Of Computing 8H.2. Database Management 36H.3.1. Content Analysis And Indexing 89H.3.3/Clustering 18H.3.3/Information Filtering 15H.3.3/Query Formulation 50H.3.3/Retrieval Models 135H.3.3/Search Process 34H.3.4. Systems And Software 18H.3.5. Online Information Services 8H.5. Information Interfaces 17I.2. Artificial Intelligence 42I.5. Pattern Recognition 14I.7. Document And Text Processing 10J. Computer Applications 8

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Memes & Changing language

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