Evolution in Nature und Culture Prospects and problems of - - PowerPoint PPT Presentation

Evolution in Nature und Culture

Prospects and problems of generalized evolution theory

Gerhard Schurz (DCLPS, HHU Düsseldorf) schurz@hhu.de (Evolution in Natur und Kultur, Spektrum Akademischer Verlag, Heidelberg 2011. Englisch translation in progress)

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• 1. From biological to cultural evolution

The theory of biological evolution theory has frequently been misinterpreted: automatically leading to higher development survival of the strongest The generalized theory of cultural evolution is a comparatively young research program Richard Dawkins (1976): memes – as cultural counterparts of genes Culture ‚in the broad sense‘: reproduction of acquired (not genetically inherited) traits (different from to sociobiology) Co-founders of generalized theory of evolution: Charles S. Peirce, James M. Baldwin, Karl Popper, Donald T. Campbell, Daniel Dennett ... Cafalli-Sforza and Feldman (1973) Boyd and Richerson (1985) Susan Blackmore (1999): memetics (overstatements …) Evolutionary game theory (Weibull, Skyrms, ...)

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• 2. Three (abstract Darwinian) components of generalized evolution:
• 1. Reproduction: Evolutionary systems reproduce themselves in the

form of successive generations.

• 2. Variation: Reproduction brings along variations that are themselves

reproduced (inherited). (variation rate not too high)

• 3. Selection: The effective reproduction rate = fitness of different

variants in the given environment is different. The absolute population frequency is upper-bounded because of limited ressources. Therefore the fitter variants replace the less fitter ones (i.e., there is selection). Stability condition for directed evolution: The selection 'forces' (conditions) don't change for many generations ─ or if they do, then in a regular and easily predictable way. The evolutionary tree of descendance: Diversity of variants arises mainly through specialization towards different ecological niches. "No diversity without partial separation" Under equal selection conditions evolution tends to eliminate diversity, except via special mechanisms: 'balanced polymorphism'.

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Moreover, nonadaptive processes in evolution: Selectively neutral mutations → random drifts (without selection) E.g., In BE: neutral amino acids In CE: evolution of language Clarifications from the philosophy of science perspective: There are no evolutionary ‚forces‘ sui generis. Evolutionary ‚forces‘ supervene on ordinary physical forces. Empirial content of the theory of evolution: Is not contained in the most general laws of evolution. "Selection of the fittest" is a tautology (cf. Sober 1993) → Most general laws are mathematically valid (If… Then...) The empirical content is contained in the assertion that there ARE (or have been) these and those evolutionary systems and processes. The simultaneous implementation of all three modules of evolution is an extremely rare phenomenon in our universe.

• Cf. Ward/Brownlee 2000, Rare Earth.

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Is cultural evolution more than a mere metaphor? Thesis: Yes

• General. Evol.

Biological Evol. (BE) Cultural Evolution (CE) Evolutionary Organisms in their Human societies systems environment Reprones Genes in the cell Memes / acquired information nucleus software of our brains Phenetic Organs, abilties Skills, behavioral patters, traits language, ideas, technology Variations Mutation, Interpretation, guided vari- recombination ation of passed on memes Reproduction Replication, DNS-copy Imitation, social learning sexual reprod., diploid asexual, blending inheritance Selection ─ Via higher reproduction rate of ─ genes memes

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Further generalizations of evolution theory: e.g. RNA chains Protoevolution: retention instead of reproduction (D.T. Campell). → Focus of this talk: CE.

• 3. Why should we transfer the theory of evolution to the development of

cultures? 3.1) CE is neither reducible to BE … → mainly because of the speed of CE: genetic similarity between human and chimpanzee (further reasons, e.g. human creativity) … nor to the achievement of individuals (individual learning) → because CE transcends millionfold what individual geniuses can achieve 3.2) The non-intentionality of CE ─ it doesn't seem to follow global plans → Who wanted all that? The example of technological evolution (Basalla 1988): E.g. automobile 1900 vs. today; internet; mob. phone; … global warming. → simultaneous production of new technology & new demand.

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There are many parallelisms between BE und CE, also between their subfields (e.g. genetics – neuroscience; cf. Mesoudi). Even more: Generalized theory of evolution = unification of biological population dynamics, memetics and evolutionary game theory

Yet there is severe critique of memetics:

Memes are not 'viruses of the mind' (++). Memetics is not a science of its own (+). CE is not applicable to humans and cultures (-). We have to ask: what are the differences between BE and CE? General Evol. Biological Evol. (BE) Cultural Evol (CE) D for " structural difference" Evolutionary Organisms in their Human societies systems environment Thus, CE takes place within BE Reprones Genes in the cell Memes / acquired information nucleus Software of our brains D: Identity Molecular & functional Only functional definition conditions definition problem of vagueness

Evolution in nature und culture Gerhard Schurz GENEVO Düsseldorf 2018

BE: CE: Phenetic Organs, abilties Skills, behavioral patterns, traits language, ideas, technology D: clear ← distinction repron - phen → unclear (!) Variations Mutation, Interpretation, guided vari- Recombination ation of passed on memes D: mostly (S-) undirected goal-directed (but fallible) D: Macrovariations Macrovariations ('revolutions') difficult easier possible Reproduction Replication, DNA copy Imitation, social learning D: syntactic semantic D: sexual reprod., diploid asexual, blending inheritance D: Species: intrinsic Quasispecies: no intrinsic reproducion barriers reproduction barriers D: Tree of descendance Graph of descendence (only branching) (merging possible) unique ←next common ancestor → ambiguous

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BE: CE: Selection ─ Via higher reproduction rate of ─ genes memes D: Usually frequency Often frequency dependent independent Direction becomes easily stable direction instable D: Criteria of fitness: Criteria of fitness: heterogeneous depends on ecological Question of power: who determines niche the selection parameters? D: Fertility fitness Meme dissemination, advertising Barriers: Barriers: Offspring ends in Dictatorships: meme prohibitions food chain Information societies: Meme filters D: Survival fitness: Dictatorship: coercion, indoctrination Survive until reproduct. Democracies: Meme freedom Water, nutrition, temp. Meme 'survival' in argumentation: Protection against Connection with rationality ? predators Higher truth chances ?

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• 6. Towards a unified theory of evolutionary systems

6.1 Frequency-independent selection − standard case of BE: General equation: Xi = competing variants Next(f(Xk)) = f(Xi) = frequency of Xi Next(f) = f in next generation Stability condition: Next(f(Xk)) = f(Xk) Selection of advantageous & dominant allele A with backward mutation Genotypes: AA Aa aa Frequencies: f2 2f(1−f) (1−f)2 where f(A) = f, f(a) = 1−f Relative Fitness: 1 1 1−s s = selection disadvantage Effective mutation rate: m: A→a Calculation gives: Next(f)) = f.(1−m). Stability condition, Next(f*) =! f*, implies f* = 1 −

Evolution in nature und culture Gerhard Schurz GENEVO Düsseldorf 2018

f(Xk).fitness(Xk)

Σi f(Xi).fitness(Xi)

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→ Result: directed evolution (stable equilibrium) almost-fixation of A 6.2 Analogous in CE, but without diploidy; thus even simpler: Selection of advantageous meme with backward 'mutation' m: A → B Memes: A B Calculation gives: Frequencies: f 1−f Next(f)) = f.(1−m). Relative Fitness: 1 1−s Stability condition implies: Mutation rate: m: A→a f* = 1 − (m/s)

Evolution in nature und culture Gerhard Schurz GENEVO Düsseldorf 2018

Frequency 1 f*(A) = 1−

s m

Evolution condition: m < s f*(a) =

s m

Generations

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Further examples of frequency-independent selection: Multiple niches with niche-dependent selection and migration May produce polymorphism (gene/meme diversity within one population) (example: cultural selection of women wearing headscarfs)

6.3 Frequency-dependent selection (especially important for CE)

The fitness of a variant (in a given enivironment) depends on the frequency of itself or of other variants Reflexive freq.-dependence Interactive freq.-dependence (BE: interspecies, predator-prey) CE: evolut. game theory Negative refl. freq.-dep. Positive refl. freq.-dep. (e.g. fashions) (e.g. conformism)

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6.3.1 Negative reflexive frequency-dependence Fashion memes A and B attractivity sinks with its own frequency Linear dependence leads to polymorphic equilibrium Quadratic dependency: Memes fashion A fashion B Frequencies f(A) f(B) [= 1 ─ f(A)] Relative fitnesses: (1─f(A))2 (1─f(B))2 Leads to perpetual cycles: Calculation yields: Next(f(A)) = 1─f(A) Non-trivial equilibrium doesn't exist. Leads for all start values ≠ 0,1 to cycles between f and 1─f. Lumsden and Wilson (1981): empirical study of clothing styles: mixed freq.-dependence: 'innovation' (neg. ) and 'status' (pos. dep.)

2 4 6 8 1 . 2 . 4 . 6 . 8

Meme generations

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6.3.2 Positive reflexive frequency dependence Given a stable mixed 1:1 equilibrium of two memes A, B (Positive A-selection, sB = 0.2), and backward mutation m: A→B, m = 0.1) Add exponential positive frequency-dependence (linear not enough) Variants A B Fitness: 1⋅cf(A) (1−s)⋅cf(B) Leads to conformism: The stable 1:1 equilibrium becomes instable and accelerates to a 100% extreme end state for all start values ≠ 0.5.

Frequency of A almost-extiction of B (recreation by mutation) generations extinction of A

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6.4 Interactive frequency dependency and evolutionary game theory Symmetric 2-person games with two possible actions A1, A2 Player 2: A1 A2 Player 1: A1 (play altruist) u11 u12 f(A1) = f A2 (play egoist) u21 u22 f(A2) = 1─f Memes: A1 A2 Frequencies f 1─f Fitness: f∙u11 + (1─f)∙u12 f∙u21 + (1─f)∙u22 Same equation: Next(f) = Stability condition, Next(f*) = f* yields general solution:

f*triv = 0 or 1 f*mix=

12 22 21 11 12 22

u u u u u u

− + − −

Evolution in nature und culture Gerhard Schurz GENEVO Düsseldorf 2018

) u f) (1 u f ( f) (1 u f) (1 u f ( f u ) f (1 u f ( f

22 1 2 12 11 12 11

) )

− − − −

+ + + +

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There are only 3 (or 4) basic types of these games (Weibull 1995): 6.4.1 Coordination game finding conventional agreement i.n.s.: u11, u22 > u12, u21 e.g. A1 A2 A1 3 A2 1 4 i.w.s.: u11 > u21 & u22 > u21 e.g. 2 3 hare versus stag hunt game (Skyrms 2005) 0 4

f = f(A1)

Stable equilibrium f* = 1 1 instable equilibrium f* = 0.5 0.5 Stable equilibrium f* = 0 generations

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6.4.2 Fight–yield (hawk–dove) game condition: u12 > u11 > u21 > u22 e.g.: Y F Y 3 F 6

• 2

Evolution in nature und culture Gerhard Schurz GENEVO Düsseldorf 2018

f(C) 1 f* =1: unstable Mixed equilibrium f* f* stable f* = 0: unstable generations

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6.4.3 Cooperation game - prisoners dilemma C = cooperation (help), D = Defection (don't help) Examples: food sharing, mutual aid, maintenance of common goods ... Conditions: u21 > u11 > u22> u12 e.g. C D [ u11 > (u21+u12)/2 ] C 3 D 4 1 As long as there are altruists, they are exploited by egoists. Thus C is doomed to die out, although C-C is Pareto optimal . How can C be stabilized? By sanction & reward in iterated cooperation game.

f(C)

f(C)=1: instable equilibrium 1 f(D)= 1: stable equilibrium generations

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• 7. The evolution of cooperation

Three types of strategies (with gradual borderlines): The exploitive egoist: Let others help him without helping others. The naive altruist: helps all others, even the egoists. Cooperation-friendly retaliators: First cooperate, then Tit for Tat (Axelrod 1984) Problem: There are many strategy variants in the iterated prisoners dilemma, but no one of them is evolutionary stable. Arnold 2008: simulation series with all possible 5 bit strategies Purple: naive altruists; dark blue: exploiters, light blue TFT variants

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Possible mechanisms of stabilizing cooperation:

• 1. Group selection with ongoing regrouping (Sober & D. Wilson 1998)
• 2. Communication & correlated pairing – signaling game (Skyrms 1996)
• 3. Institutionalized sanctioning mechanisms (Gürek et al 2006)
• 4. Cognitive mechanisms of cheater detection (Tooby&Cosmides 1995)
• 5. Religious stabilization of altruism (D. Wilson 2002)
• 8. Conclusions

−There is no special discipline of CE; CE is interdisciplinary. − Defining the identy of memes is still an open problem; but this does not constitute a barrier to the progress of CE. − The core of generalized evolution theory is applicable to BE and CE. − It consists of the three components of evolution together with the general theoretical-mathematical models, solution techniques and classicifations of evolutionary scenarious and their stability propertes. − There also exist important differences between BE and CE. Some of these differences have different implications for practical action.

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Literatur 1 Arnold, E. (2008): Explaining Altruism. An Simulation-Based Approach and Its Limits, Ontos- Verlag, Frankfurt/M. Axelrod, R. (2006): The Evolution of Cooperation (revised edition), Basic Books, New York (orig. 1984). Aunger (2002, ed.): Darwinizing Culture: The Status of Memetics as a Science, Oxford Univ. Press, Baldwin, J. M. (1909): Darwin and the Humanities, Review Publ. Co., Baltimore. Blackmore, S. (2000): The Meme Machine, Oxford Paperbacks. Boyd, R. and Richerson, P. J. (1985): Culture and the Evolutionary Process. Univ. of Chicago Press. Campbell, D.T. (1974): “Evolutionary Epistemology”, in: Schillp, P.A. (ed.), The Philosophy of Karl

• Popper. La Salle.

Cavalli-Sforza, Luigi and Feldman, Marcus W. (1981), Cultural Transmission and Evolution. Princeton: Princeton University Press. Cavalli-Sforza, L. (2001): Genes, Peoples and Languages, Penguin Books, London. Cosmides, L. und Tooby, J. (1992): „Cognitive Adaptations for Social Exchange“, in: Barkow, J., Cosmides, L. und Tooby, J. (eds.) (1992): The Adapted Mind: Evolutionary Psychology and the Generation of Culture, Oxford Univ. Press, New York,163–228. Dawkins, R. (1976): The Selfish Gene, Oxford Univ. Press, Oxford (new ed. 1987). Dennett, D. C. (1995): Darwin's Dangerous Idea, Simon & Schuster, New York. Dennet, D.C. (2018): From Bacteria to Bach and Back, Penguin Books, London. Fox, A. (1995): Linguistic Reconstruction, Oxford Univ. Press, Oxford. Gürek, Ö., Irlenbuch, B. und Rockenbach, B. (2006): „The Competitive Advantage of Sanctioning Institutions“, Science 312, 108–111. Inglehart, R. and Welzel, C. (2005): Modernization, Cultural Change and Democracy, Cambridge University Press, New York.

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Literatur 2 Mace, R. (2016, ed.): The Evolution of Cultural Diversity, UCL Institute of Archaeology

Publications.

Mayr., E. (1942): Systematics and the Origin of Species, Columbia Univ. Press, New York. Mayr, E. (1982): The Growth of Biological Thought, Harvard Univ. Press., Harvard. Mesoudi, A., Whiten, A. und Laland, K. N. (2006): „Towards a Unified Science of Cultural Evolution“, Behavioral and Brain Science 29, 329–347. Ruhlen, M. (1994): The Origin of Language: Tracing the Evolution of the Mother Tongue, John Wiley and Sons, New York. Pitt-Rivers, Lane-Fox A. (1906): The Evolution of Culture, Clarendon Press, Oxford 1906. Ridley, M. (1993): Evolution, Blackwell Scientific Publications, Oxford. Schurz, G. (2011): Evolution in Natur und Kultur, Spektrum Akademischer Verlag, Berlin. Schurz, G. (2013): Philosophy of Science. A Unified Approach, Routledge, New York.

Skyrms, B. (2004): The Stag Hunt and the Evolution of the Social Structure, Cambridge Univ. Press, Cambridge.

• Skyrms. B. (2014): Social Dynamics, Oxford University Press, Oxford.

Smolin, L. (1997): The Life of the Cosmos, Oxord Univ. Press, New York. Sober, E. (1993): Philosophy of Biology, Westview Press, Boulder. Sober, E. und Wilson, D. (1998): Unto Others, Harvard Univ. Press, Cambridge/Mass. Tomasello, M. (1999): The Cultural Origins of Human Cognition, Harvard Univ. Press, Cambridge/MA. Ward, P. und Brownlee, D. (2000): Rare Earth, Springer, New York (dt.: Unsere einsame Erde, Springer, Berlin 2001). Wilson, D. S. (2002): Darwin's Cathedral. Evolution, Religion and the Nature of Society, Univ. of Chicago Press, Chicago. Wilson, E. O. (1998): Consilience.The Unity of Knowledge, Vintage Books, New York.

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Appendix I: Cultural world map

• f World Value

Survey ProjectInglehart/ Welzel (2005)

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Appendix II: Tree of descendence

• f human languages

After Ruhlen (1994) and Cavalli-Sforza (2001).

Evolution in nature und culture Gerhard Schurz GENEVO Düsseldorf 2018