naccache-history of evolution

8/8/2019 Naccache-History of Evolution

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Wesleyan University

A Brief History of EvolutionAuthor(s): Albert F. H. NaccacheSource: History and Theory, Vol. 38, No. 4, Theme Issue 38: The Return of Science:Evolutionary Ideas and History (Dec., 1999), pp. 10-32Published by: Blackwell Publishing for Wesleyan UniversityStable URL: http://www.jstor.org/stable/2678056

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A BRIEFHISTORYOF EVOLUTION'

ALBERTF. H. NACCACHE

ABSTRACTI present in this papera non-reductionist rameworkof eight nested modes of evolutionthat have successively emergedto organizethe reproductionof all organisms,from theblue-greenalgae to our societies. The processesof biological, "Darwinian" volution arethose of driftduring reproduction, nd of selection. The key unitof evolutionary ime isthe generation,and its locus is the organisms' ife-cycle setup.Differentlife-cycle setupssupportdifferentmechanismsof reproduction, nd thereforedifferentmodes of evolution.By tracing he different ife-cycle setups attested hroughoutife's history,we cancharac-terizethe successive modes of evolutionwithwhichtheyareassociatedas follows: basic;reptilian; archaic mammalian;progressive mammalian;sociocultural;extrasomaticallyenhancedsociocultural; inkering;and finallyparabiological.These successively emerg-ing modes governa progressivelyreducednumberof life-forms.The first four modes are"Darwinian"n the strict sense. The fifth, or socioculturalmode, which governs whalesandelephants'societies in additionto hominoids,is alreadynot "Darwinian"n the tradi-tional sense. The last three modes have emergedwith the genus homo, throughthe pro-gressive extension of its life-cycle setups.The presentframework s to be used heuristi-cally, as a prismwith which to separate he evolutionaryspectrumof the constituentele-mentsof humanbehavior.An exampleof such a behavioralevolutionaryspectrum s pre-sentedin conclusion,and used to compare hepresentframeworkwith thoserecentlypro-posed by MaynardSmithandSzathmdryandby Foley.

Those who invoke and heed today's scientific worldview consider that humanhistory is an indivisible part of the natural history of the world. They thereforemust grant that human history cannot be divorced from life's organizing princi-ple, evolution. This conclusion is not controversial for most of the human his-torical trajectory, and no one doubts that homo sapiens' origins are rooted in thelong interplay of "Darwinian," biological evolutionary forces. However, mosthistorians and social scientists believe that these same forces cannot account forthe last few millennia of dazzling human cultures and social organization.Moreover, many today, including historians, consider that contemporary condi-tions are so unprecedented that most of human history, all the premodern humanpast, is irrelevant to the understanding of our present predicament. Coming on

1.I dedicatethispaper o ProfessorSuhaylJ.Jabbour,MD, PhD, in gratefulrecognitionof thesim-plicity with which he agreed, years ago, to teachneurophysiology o a frustrated oung sociologist,and for the graciousnesswith which, duringthe last decade, he sharedwith me the privilegesof hisAmericanUniversityof Beirutlibrarycard.


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A BRIEFHISTORYOF EVOLUTION 11the heels of the long period duringwhich humanhistoryluxuriated n its splen-did isolation, these considerationshave reinforced the belief in a deep andunbridgeable hasmbetweenhistory andevolution.2

Thisperception s incompatiblewith the contemporary vision of a grandcon-tinuityextending across all levels of realityfrom the physico-chemical systemsto the biosphere and to humansocieties and our symbols,"3and, furthermore,tdiscourageshistoriansfromcontributing o the unravelingof the complex wayshistoryemerged from biology.4

Awed andhumbled by the daily wonders of this collective unweaving of therainbow,I presenthere a "prism" hroughwhich to look at the nestingof humanhistorywithin the naturalhistory of the world. This metaphoricalprism consistsof a frameworkof eight hierarchicallynested modesof evolutionthat have gov-erned the evolution of ourlineage from the primeval cyanobacteria o present-dayhuman societies. The purposeof this frameworks to help in separating heevolutionary spectrumof the constituent elements of human behavior.A briefreview of the historyof the nature/nurture uestion introduces hispresentation,which is concluded by an example of the analytic power of the framework, ol-lowed by a briefcomparisonwith recentsimilarlyoverarching rameworks.

IIt has long been realized that we partakeof two realms,and that there arebehav-iors we do not share with other animals. This was alreadyclearly expressedinthe accountof how "steppe-raised" nkidu was brought nto the folds of humancivilization,5and was encapsulatedn Aristotle'sdefinitionof "manas a politicalanimal."

By the end of the eighteenthcentury,the nature/nurtureichotomyhad start-ed to be perceivedin a dynamic,voluntaristway. Rousseau hadpresented"theclassic form of the argument hatthe studyof humansociety must find its basisin a portraitof humannature,and specificallyin a distinction between what isoriginaland fundamentaln manandwhat is artificialandacquired,"6ndJamesBurnet(LordMonboddo)had writtenthat man makeshimself, and thatthere isno difference between man and brutes "except what culture and educationmakes."7By the early nineteenth century, belief in evolution and culturalprogresshad becomewidespreadn Europeanntellectualcircles.Thisbelief wasfurtherlegitimized by Lyell's evolutionary views, which were based on themethod of scientific inquiry,and in which Earth'sgeology was understoodas

2. History and Evolution, ed. M. H. Nitecki and D. V. Nitecki (Albany, 1992); A. L. Kroeber,"Evolution, History, and Culture," in Evolution after Darwin: The Evolution of Man, ed. S. Tax(Chicago, 1960), 1-15.

3. W. H. McNeill, "Historyandthe Scientific Worldview,"History and Theory37 (1998), 1-13.4. M. Polanyi, The Studyof Man (Chicago, 1958).5. Old-Babylonian"Epicof Gilgamesh" eighteenth-centuryBC).6. K. Bock, HumanNature and History:A Response to Sociobiology (New York, 1980), 17.7. Ibid., 20.


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12 ALBERTF. H. NACCACHEproducedby processes actingthrough ong periods of time. It is in this contextthat Darwinand Wallace proposedthe theory of natural election asan explana-tion for the originof species.

In The Descent of Man, Darwin hadalready ntroducedcausalprinciples spe-cific to human evolution, but it was HerbertSpencer,who had "introduced heterm'evolution' n its presentsense,"8who firstrecognizedthe existence of adis-tinct "super-organic social) evolution." Spencer wrote that social evolution"must have come by insensible steps out of the organic . .. (and that)we mayconvenientlymark .. (it) off as includingall thoseprocessesandproductswhichimply the co-ordinatedactions of many individuals."9

Spencerwas an influentialproponentof explanatory rameworksof societalchange, and "Spencerian"deas prevailedin anthropologyand spilled over tohistory,while the existence of a "superorganic" ind of evolutionbecame gener-ally acknowledged n the social sciences.'0 This situation asteduntil the secondhalf of the twentieth century, when "Spencerian" deas were recognized asLamarckianand rather teleological in nature, and when the excesses of"Spencerian"ocial evolutionism led to its passing away."I

These ideas were dismissed, however, without being subjected to criticalreevaluation.Most social scientists, fromtraditionalist istorianswho still adopta common-sense, ordinary-lifeontology of action, to "world-system" ractition-ers who do not shunthe "e-word"andspecifically address he issue of the mech-anisms of social andhistoricalchange,'2 do not connect theiranalyses to the bio-logical realm. The consensus today seems to be "that culturalevolution is nolonger 'checked' for survivalrelevance n the strictlyDarwinian ense, [andthat]natural electioncannot be invoked to explain culturalevolution."'13

Meanwhile, evolutionarybiologists hadrejectedthe "Spencerian"deas earlyin the twentiethcenturyandignoredthe issue of "superorganicvolution" untilthe 1970s. At that time they reappliedbiological models to explainhuman soci-eties, their many schools'4 undeterredeither by the above-mentioned social-

8. On the EvolutionaryUniquenessof Man, ed. T. Dobzhansky (New York, 1972), 428.9. H. Spencer,Principles of Sociology (London,1885), 4.10. V. G. Childe, Man Makes Himself, 3rd ed. (London, 1956); A. L. Kroeber,The Nature ofCulture(Chicago, 1952); B. G. Trigger, "Archaeologyand Epistemology:Dialoguing across theDarwinianChasm,"AmericanJournalofArchaeology 102 (1998), 1-34; J.L. Boone and E. A. Smith,"Is it Evolution Yet?"CurrentAnthropology39, supplement 1998), 141-173.11. T. B. Bottomore,Sociology:A Guide to Problems and Literature New York,1971), 53.

12. C. Chase-DunnandT. D. Hall, Rise and Demise: ComparingWorld-SystemsBoulder, 1997).13. P. A. Corning, "Politics and the EvolutionaryProcess," in EvolutionaryBiology, ed. T.Dobzhanskyet al. (New York, 1974), 276.14. R. Boyd andP.J. Richerson,Cultureand theEvolutionaryProcess (Chicago,1985); Boyd andRicherson,"WhyCulture s Common,but CulturalEvolution s Rare,"n Evolutionof Social BehaviourPatternsin PrimatesandMan, ed. W. G. Runcimanet al. (Oxford,1996), 77-93; J. N. Davis and M.Daly,"Evolutionary heoryand theHumanFamily,"QuarterlyReviewof Biology 72 (1997), 407-436;W. H. Durham,"Advances nEvolutionaryCultureTheory,"AnnualReviewofAnthropology19(1990),

187-210;S. T.Emlen,"AnEvolutionaryTheoryof the Family,"Proceedingsof theNationalAcademyof Sciences USA92, no. 18 (1995); J. Horgan,"The New Social Darwinists,"ScientificAmerican273(1995), 150-157; C. J. Lumsdenand E. 0. Wilson, Genes, Mind and Culture:The CoevolutionaryProcess (Cambridge,Mass., 1981); E. 0. Wilson, "EpigenesisandtheEvolution of Social Systems,"


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A BRIEFHISTORYOF EVOLUTION 13science consensus,or by specific warnings,'5 rom considering thatthe mecha-nisms of biological evolution-random mutationand selection-are enough toaccount for culturalevolution.

Recently, interdisciplinary pproaches o the studyof humanorigins,'6and tothe development of intelligence and/or languages have mushroomed.Yet, theevolutionary orces specificallyresponsible for humankind'sorigin and destinyare still shrouded n confusion:

1. They lack a recognized name,being variously referred o as superorganic,superorganicocial, cultural, ociocultural,noetic,psychosocial,exogenetic,exo-somatic,ormetabiological.

2. The estimatesabout heironsettime,whichtraditionallylusteredaroundwomillionyears ago),'8now rangefrom five million'9 o thirty housandyearsago.20Journal of Heredity72 (1981), 70-77. The analogy drawn between biological andculturalevolutionis particularly lear in C. F. Swanson, Ever-ExpandingHorizons: The Dual InformationalSources ofHumanEvolution(Amherst,Mass., 1983).

15. F. Jacob, "Evolutionand Tinkering,"Science 196 (1977), 1161-1166.16. R. Foley, "Causes and Consequences in HumanEvolution," Journal of the Royal Anthro-

pological Institute n.s.) 1 (1995), 67-86; D. Pilbeam, "MajorTrends n HumanEvolution," n CurrentArgumenton EarlyMan (Oxford, 1980).

17. Among many: L. C. Aiello, "Terrestriality, ipedalism and the Origin of Language," nRunciman, d.,Evolutionof Social BehaviourPatterns;Aiello, "TheFoundations f HumanLanguage,"in The Origin and Diversificationof Language,ed. N. G. Jablonskiand L. C. Aiello (San Francisco,1998); L. C. Aiello and R. I. M. Dunbar,"NeocortexSize, GroupSize, andthe Evolutionof Language,"CurrentAnthropology34 (1993), 184-193; D. Bickerton,Language & Species (Chicago, 1990); R.Burling,"PrimateCalls,HumanLanguage,and NonverbalCommunication," urrentAnthropology4(1993), 25-53; M. Chazan,"TheLanguageHypothesis or the Middle-to-Upper aleolithicTransition:An ExaminationBased on a MultiregionalLithicAnalysis,"CurrentAnthropology 6 (1995), 749-766;D. L. Cheney and R. M. Seyfarth,"Functionand Intention n the Calls of Non-HumanPrimates,"nRunciman, d., Evolutionof Social BehaviourPatterns,59-76; N. Chomsky,"LanguageandNature,"Mind 104 (1995), 1-61;T. W. Deacon, TheSymbolicSpecies: The Co-evolutionof Languageand theBrain (New York,1997);K. R. Gibson,"ToolUse, Languageand Social Behaviour n Relationship oInformation rocessingCapacities,"n Tools,Languageand Cognition n HumanEvolution,ed. K. R.Gibson and T. Ingold (Cambridge,Eng., 1993), 251-269; D. F. Jonas and A. D. Jonas, "GenderDifferences n MentalFunction:A Clue to the Originof Language,"CurientAnthropology16 (1975),626-630; J. L. Locke, "WhyDo InfantsBegin to Talk?Languageas an UnintendedConsequence,"Journal of Child Language23 (1996), 251-268; P. Marler,"Animal Communicationand HumanLanguage," n Jablonskiand Aiello, ed., Origin and Diversification, 1-19; M. Maxwell, HumanEvolution:A PhilosophicalAnthropology New York, 1984); R. G. Milo and D. Quiatt,"GlottogenesisandAnatomicallyModem Homo Sapiens:The Evidence forand Implications f a Late Originof VocalLanguage,"CurrentAnthropology34 (1993), 569-598; S. Mithen,The Prehistoryof the Mind: TheCognitiveOriginsofArt, Religionand Science(London,1996); S. Pinker,TheLanguageInstinct NewYork, 1994); M. S. Seidenberg,"LanguageAcquisition andUse: Learningand Applying ProbabilisticConstraints," cience 275 (1997), 1599-1603;I. Tattersall,BecomingHuman:Evolutionand HumanUniqueness (New York, 1998); I. Stewart and J. Cohen, Figments of Reality: The Evolutionof theCuriousMind(Cambridge,Eng., 1997);W. H. Thorpe,Biologyand the Natureof Man(London,1962).18. Dobzhansky,ed., On the Evolutionary Uniquenessof Man;T. N. Timbergen,"Ethologyin aChanging World," n GrowingPoints in Ethology, 507-527, ed. P. P. G. Bateson and R. A. Hinde(Cambridge,Eng., 1976).

19. K. R. Gibson, "The Ontogeny and Evolution of the Brain, Cognition, and Language,"inHandbookof HumanSymbolicEvolution,ed. A. Lock and C. R. Peters(Oxford, 1996).

20. W. Noble and I. Davidson, Human Evolution, Language and Mind: A Psychological andArchaeologicalInquiry(Cambridge,Eng., 1996).


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14 ALBERTF. H. NACCACHE3. Even their number s still in doubt,some proposalsdistinguishing wo phas-

es or levels,2' while one distinguishesthree phases, two within "metabiological(cultural)evolution"-corresponding to the emergenceof the humanmind andof the human cultures-and a third,called "teleobiological,"resultingfromtheemergence of "global values."22

This is my excuse for the boldness of the present attempt,which requiredroaming over the "grand,evolving story featuring spontaneous emergence ofcomplexity that generates new sortsof behavior at every level of organizationfrom the minutestquarksand leptons. .. to the symbolic universes of meaningwithin which humanbeings live andlabor,"23ooking for patterns hroughwhichpresent-dayhuman culturalevolutionmight have evolved from biological evo-lution.

IIDuringthe firstone-ten-thousandthf a secondaftertheuniversestartedexpand-ing from its original singularity,matterexisted only as subatomic hadrons,andits evolutionwas governedby theforce of strong nteraction.During the next tenseconds, the electrons and other leptonsappeared,andthe force of weakinterac-tion took over as the governingfactor in the behaviorand reactionof the uni-verse.Then,radiationgovernedfor roughlyone million years,till the hydrogenatoms formedand thecooling universeentered ts fourthand still ongoing StellarAge, in which gravity presidesover the cosmic carouselof stars andgalaxies.

Seven to eight billion years into the StellarAge, a succession of stellar lifecycles had seeded a local interstellarcloud in the peripheryof the Milky Waygalaxy with all the elements, from helium to uranium.This cloud was denseenoughto startcontractingunder ts own gravity.The nascent solarsystem wentthroughdistinctphases of varyingratesuntil, some 4.55 billion years ago, therockyinnerplanets-Venus, Earth,andMars-had formed.Initially,these threedense-cored isterplanetshadverysimilaratmospheres,andon theircooling sur-faces watercondensed to form oceansandglacial deposits. However,Venuswasclose enoughto the Sun for a runawaygreenhouseeffect to vaporizeall its sur-face water,and Marswas bothfarenoughfromthe Sunfor all its waterto freeze,andof a masstoo smallto retainmuch of anatmosphere.Of the three sisterplan-ets, only Earthcould retain its oceans. The marginwas slim. Had Earthformed5% closer to the Sun it would have suffered Venus's fate. Had its orbit beenpushed 1%fartheraway, runawayglaciationwould have set on its surface,as itdid on Mars.

This cursorylook at the first two-thirds of the history of the world shouldremindus that even the physicalmechanismsof changehave a history,andthatthey arecontingentand condition-bound.

21. T.Dobzhanskyet al., Evolution(SanFrancisco, 1977); D. C. Johanson,"TheHumanCareer,"Humanist 1983), 22-24; P.Teilhardde Chardin,Laplace de l'hommedans la nature (Paris,1956); J.C. Eccles, Evolutionof theBrain: Creationof theSelf (London, 1989), 220.22. J. Salk, TheAnatomyof Reality (New York, 1985).

23. McNeill, Historyand the ScientificWorldview,13.


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A BRIEF HISTORYOF EVOLUTION 15As it happened, four billion years ago Earthhad weatheredthe major aster-

oids' impacts, and its oceans were being seeded by organic molecules from theprotoplanetary ust and energized by lightningand by solar ultravioletradiation.Undertheseconditions, the evolutionof moleculeson Earth'scrust startedbeingdominatedby the processes of organicchemistry.The storyof the emergenceofvarious macromolecules, romwhich eventually developed the first autocatalyt-ic, self-replicating,and self-assemblingmacromoleculeable to reproduce tselffaster than it would naturallydegradein an aqueous environment, s progres-sively being uncovered.In synergy with lipid membranes,andcatalyzed by theenvironment,one such macromolecule entered the bootstrappingpath of near-perfect reproductionunderenvironmental anction.With the emergenceof thispolynucleotide, the abiotic eons had ended, and the history of life on Earthbegun.

Over the following 3.8 billion years, life's realm extendedfrom blue-greenalgae to human societies. Life's basic components being the physicochemicalelements of the inorganic world, all of life's denizens obey the fundamentalphysicochemical aws thatgoverntheircomponents'behaviorin nonliving mat-ter.However,thephysicochemicalmechanismsonly set limits to life, and do notgovern its blooming. Clearly, within today's scientific worldview, the"Darwinian"mechanism s the only candidateconsidered or thatgoverningtask.But, as clearly,the ability of this latter to account, on its own, for all of life'sefflorescence, up to and includingthe developmentof humansocieties, is whatis being debated.

The guidingintuitionof the presentsearch was that,when looked at in histor-ical perspective,the "Darwinian"mechanismof evolution should turnout to be,like thephysical laws, contingentand condition-bound. n otherwords,the intu-ition was that there are intermediary, istorically unfolding,hierarchicalmodesof evolution withinthe overarching"Darwinian"volutionarybiological mech-anism, and that uncoveringthese intermediarymodes might help bridge thechasm between historicalandbiological evolution.

The viewpoint adoptedfor this historical survey is that of the "Darwinianmetaphysicalresearchprogram,"24which has amply proved its productivity.Natural election,the "law"of the Darwinianmechanismof biological evolution,is powered by differentialreproductive itness,and is thus a function of the var-ious factorsaffecting reproduction. thereforenarrowedmy searchto look at thefactors that have affected how the successive organismshave managedtheirreproduction.Even thoughbiological evolution is implemented hroughprocess-es that occur over geological time, its key unit of time is the generation,and itslocus is the organisms' ife-cycle setup (the way its reproductiveprocessesandbehavioralrepertory ontribute o the productionof offspring).25

The evolutionarysequencethat has led to Homosapiens sapiens is character-ized by increasingly complex organismsendowed with increasingly complex

24. K. Popper, UnendedQuest:AnIntellectualAutobiographyLondon, 1986).25. Foley, "Causesand Consequences,"77.


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16 ALBERTF. H. NACCACHEbehavioral repertories and engaging in increasingly complex reproductiveprocesses. Skirting the general issue of evolutionary progress,26 or which westill have no convincing account,oreven a satisfactorydefinition,27 acceptedasprimarydata the advances in complexities displayed by the organismsthat con-stituteourparticular ineage,28 nd attemptedo discernpatternsn thehistoryoftheirlife-cycle setups.

During a period stretching over roughly three and a half billion years, lifeforms evolved fromthe primitive "mother"molecule, whose phenotypeconsist-ed of only one catalytic enzyme, to the exuberant ife forms participatingn thetrophicchainof theCambrian ra. Sexual reproduction mergedduring hatperi-od, as well as multicellularorganismsendowed withcentralnervoussystems thatcould sustainmorethan simple reflex activities.29 t is to the earliest organismsdisplaying exceedingly simple sense organsthat we can trace the roots of ourintellectual abilities. The senses that developed in order to mediatethe pre-Cambrianorganisms' nteractionswith theirenvironmentshad an inherentten-dency to "organize he sensory field into groupsand patternsof sense-data, toperceive forms rather hana flux of light-impression.... This unconscious appre-ciation of forms is the primitiveroot of all abstraction,which in turn is thekeynote of rationality."30 owards the end of that period, organisms mightalreadyhave acquired orms of associativelearning.31

Yet, the life-cycle setupof all the organisms reproducingduringthe eons ofthatperiod, despite theirdiversity,is definedby the following two characteris-tics: 1) the variation rom one generation o the next has its sole source n theran-dom mutations, recombinations,and errors of reproduction hathappento thegenetic material,the genome, duringits replication;2) the behavioralstrategypursuedby all these organismswas one of fending solely for themselves,evenafter their internalconditions had become rightfor theirgenome's replication ohappen, hat s, they followedan individualistic urvivalstrategy hatdid nottakeinto accounttheiroffspring.

This life-cycle setupdefines the "Basic Mode of Evolution"(MoE) represent-ed in Figure 1,32 in which the phenotypestands for the total morphologyand

26. "The otherwise inexplicable tendency of organismsto adoptever more complicated solutionsof the problemof remainingalive,"P.Medawar,TheArtof the Soluble (London, 1967).

27. T. Dobzhansky,"Chanceand Creativity n Evolution," n Studies in thePhilosophy of Biology:Reductionand RelatedProblems,ed. F. J. Ayalaand T. Dobzhansky(Berkeley, 1974), 310.

28. F. J. Ayala,"TheConceptof Biological Progress," n ibid.29. W. H. Thorpe, "Reductionism n Biology," in Ayala and Dobzhansky, ed., Studies in the

Philosophy of Biology, 118; G. 0. Mackie, "TheElementaryNervous System Revisited,"AmericanZoologist 30 (1990), 917.

30. S. K. Langer, Philosophy in a New Key:A Studyin the Symbolismof Reason, Rite, and Art(Cambridge,Mass. 1941), 89.31. E.A. Arbaset al., "Evolutionn NervousSystems,"AnnualReview of Neuroscience14(1991),

9-38; T. J. Carew and C. L. Sahley, "Invertebrate earningand Memory:From Behavior to Mole-cules,"AnnualReview of Neuroscience 9 (1986), 435-487.32. J. T. Bonner, Size and Cycle:An Essay on the Structureof Biology (Princeton, 1965), 12; see

also Boyd and Richerson, Cultureand the EvolutionaryProcess, 5-6 and21.


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A BRIEFHISTORYOFEVOLUTION 17

DN ; At0 Phenotype.: |Sexualreproduction

Innovation Elimination

Genome DNA Phen~~~~~~otype

Figure 1. Life-cycle setupfor the Basic Mode of Evolution3.8 billion years ago

behavioral repertory of the organism,33 and the arrows linking genotypes andphenotypes stands for the whole chain of causation leading from one to theother.4

Sexualreproductionmultipliedthe potentialof variation rom one generationto the next,but did not affect the source of variation,which remained solatedinthe genome . Even though organismsendowed with new biological functionali-ties emergedduringthatperiod,andengagedin purposeful,"intelligent"behav-ior that increasedtheir chance of achieving reproduction,3 hey still engagedinthe same individualisticsurvivalstrategy.Thus these two otherwise momentousdevelopmentsdid not affect the life-cycle setupof the basic MoE, which is stillfollowed today by organismsrepresentinga largepercentageof Earth'sbiomass.They did, however,increase the potentialfor producingorganismshaving evermore complex phenotypes adapted to more and more specialized environments.

J. Eccles, refining Karl Popper's differentiation between "passive" andactivev"Darwinism,defined the latter as having appearedsome 200 millionyears ago when highly developed organismsstarted to explore their environ-ment.36 Lumsden and Wilson used five "grades of cultural behavior" as an organizing principle for their "evolutionary classification."37 Keeping to our birds'-eye view,we notea qualitativedevelopment n the life-cycle setupwhenthepar-ent phenotypestartedcontributing,n an organic way, to the organic growthofthe next generationgenome.This happenedwith the emergenceof the amnnioteegg, a protectedenvironmentprovidedby the parentphenotypefor the expres-sion of the offspring's genome.

Tryingto tag the behavioral correlateof this physiological developmentto aspecific stagein the long process of mind'semergence,we follow G. Edelman's

33. R. Dawkins, The ExtendedPhenotype: The Long Reach of the Gene (Oxford, 1989), 230.34. To avoid visual cluttering,the recurrentmentions have been indicated only the first time.

Furthermore, ime indices for successive generations(such as gI and g2, orfl andf2), and the con-stant factors,such as energyandchemical compounds nputs, have not been represented.35. S. R. Hameroff,"Did ConsciousnessCausetheCambrianEvolutionaryExplosion?" n Toward

a Scienceof ConsciousnessII, ed. S. R. Harneroff t al. (Cambridge,Mass., 1998), 421-438.36. Eccles, Evolutionof the Brain, 217.37. LurnsdenandWilson,Genes,Mind and Culture.


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18 ALBERTF. H. NACCACHE"Theoryof NeuronalGroup Selection,"which correlatesbetter with morpholo-gy than any of the competing schemes.38The evolutionarydevelopment of thesensory fields'ability to organizedata into patterns Langer)or "self-categoriza-tion" (Edelman),and, from there,progressively ntoscenes, led to theemergenceof "primary onsciousness,"which"providesa meansof relatingan individual'spresent nput to its acts and pastrewards."39 his enhancedbehavioralplasticityand adaptabilitynot only increased the individual organism's fitness, but itenabledthe oviparousreptiles that possessed it to choose a favorable environ-ment in which to lay their eggs. This greatly mprovedthe chances of survivaloftheir offspringwho were readyto carry on in the appropriate nvironmentassoon as they hatched. Note that these developmentstook place without anynoticeable enlargementof the brainbetween amphibiansand early reptiles.

The amnioteegg, in conjunctionwith primaryconsciousness(and a scaly skinprotection), openedto vertebratesall the terrestrial nvironmentsalreadycolo-nized by plants and insects. Currently stimatedto have emerged some 300 mil-lion years ago, these developmentsof the life-cycle setup affected thesurvivalof

~DNA Phnotype

DNA(em; : Phenotype

Figure2. Life-cycle etup or theReptilianModeof Evolution(Reptiles) 00 millionyearsago ..the nextgenerationphenotypemassively enoughtojustify considering hat,withthem, a new ME had emerged. I call it the "Reptilian ME," and represent it inFigure 2, in which the highlightedsolid arrow, inking the parentphenotypetothe organicgrowthof thenextgeneration'sphenotypedevelopment, ndicatesthecharacteristic f the reptilian ife cycle setup.

The next development of the reproductive ife-cycle setup that qualitativelymodified the processesof survival of the second-generationphenotypewas theemergenceof a parentalbehavioralcontribution o the organic growth of thenext generationgenome.The morphologicalcorrelateof this development s the

38. G. M. Edelman, The Remembered Present: A Biological Theory of Consciousness (New York,1989); Edelman, BrightAit; Brilliant Fire: On the Matter of the Mind (New York, 1992); P. M.Churchland,The Engine of Reason, the Seat of the Soul: A Philosophical Journey into the Brain(Cambridge,Mass. 1995); see also The Handbookof Brain Theorymnd Neural Networks, ed. M. A.Arbib (Cambridge,Mass. 1995), and The CognitiveNeurosciences,ed. M. S. Gazzaniga(Cambridge,Mass., 1995).

39. Edelman, BrightAi; Brilliant Fire, 118-123.


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A BRIEFHISTORYOF EVOLUTION 19emergenceof mammalianviviparity,40ts behavioralcorrelate s parentalprotec-tion and care of the offspring.

To be able to sustain the highly complex processes involved in parentalcareof offspring, the phenotypes of these early mammals must have had the abilityfor "conceptual ategorization,"hat is, the ability to correlate n novel ways thescenes or images of primaryconsciousness. Edelmanproposes neuroanatomicalsupports or this ability,without,however, proposinga chronological rameworkforwhen it originated.To succeedas areproductive trategy,viviparitymust nec-essarily be pairedwith parentalcare, and, for extended parentalcare to be possi-ble, the brain musthave the ability to use concepts.We thereforepropose that"conceptual ategorization"mergedsome 200 million years ago, in conjunctionwith the emergence of viviparity andthe allometric ncreasein encephalizationdetectable n archaicmammals.

The additionof viviparity andparentalcare to the life-cycle setupushered nthe emergenceof the "ArchaicMammalianMoE," represented n Figure3, inwhich the highlighteddashed-linearrowconnectingparentand offspringpheno-types standsfor the parentalcare provided to live offspring.

=. ..E....D. enoty

DANA henotype

Figure3. Life-cycle setupfor the ArchaicMammalianMode of Evolution(Mammals)00 millionyearsago -0Like all featuresof evolutionary change, the developmentof parentalcare

behavior is traceable from a rudimentary expression at its inception among theprimitiveviviparousamniotes,such as the mammal-likereptiles,41o its fullerexpressionas displayedamongtoday'shighermammals. How such a sigmoid,S-shaped growthcurve2 wouldappear, moothly grainedorroughandsaltatory,would dependon the time scale atwhich it is observed.

Today,parental areof offspring s notrestricted o the mammalianbehavioralrepertory. Many species of birds, at least one species of toads, and even someinsects engage in it.43 The evolutionary pressurefor engaging in parentalcare

40. J. P.Wourmsand I. P.Callard,"ARetrospect o the Symposiumon Evolutionof Viviparity nVertebrates," mericanZoologist 32 (1992), 251-255.

41. D. W. Dilkes andR. R. Reisz, "FirstRecord of a Basal Synapsid ('Mammal-likeReptile') inGondwana,"Proceedings of the Royal Society of LondonB 263 (1996), 1165-1170.42. J. T. Bonner,TheEvolutionof Culture n Animals (Princeton,1980), 167.43. D. W. Tallamy,"ChildCare amongthe Insects,"ScientificAmerican280:1 (1999), 72-77.


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20 ALBERTF. H. NACCACHEdepends on environmentalconditions, and this behavior must have been inde-pendently developed in various phyla and classes. Mammalian and avianparentalcare behaviors do not stem from similar morphological and cognitivebases, and while some birds might have the ability for conceptualcategorization,all toads and insects do not. Most probably he parentalcare behaviorof insectsand birds is "hardwired," nd therefore ts potentialfor development s much lessthan that of mammals.

The morphological underpinningsof the next stage are not as obvious asoviparityand viviparity,and have to be inferred romthe new enlargementof thebehavioralrepertory o which they gave rise. This apparently ook place onlyamong the mammals,and can be characterizedas the emergence of parentalbehavioral interventionn the expressionof the behavioralrepertoryof the nextgeneration'sphenotype. There is much anecdotalevidence for such behavior,usuallyreferred o as "teaching,"or instanceamongcats44or lions.45The con-servative conclusions of a recent review of this hotly debated subject46areenoughto support he present argument,althoughthe growingrealizationof thedependenceof epigenesison interactionwith the environment47ends some cre-denceto the claims for a greaterrange for this behavior.48

Teachingshould be distinguishedfrom less specific forms of social learningsuch as social facilitation and local enhancementor imitation, and is normallyunderstood as directed instructionof one individual by another.The selectiveadvantageof this behavior s that thepupil "acquiresknowledgeor learnsa skillearlier n life and morerapidlyorefficientlythan it mightotherwisedo, or that itwouldnotlearnat all."49Amongmammals t is usuallyaparent,and morespecif-ically the mother, hat teaches its offspring.

At its inception at least, this novel way to increase the offspring's survivalchances did notrequireof the tutoreither thepossessionof complexintentional-ity, or the ability to attributemental states to her pupils. These abilities woulddevelop later,and only in a few species.

Theimpactof theMoE thatemergedwith this new developmentof the behav-ioral repertory s illustratedby the victory in the encephalization ace won by thepredatory arnivores,who engagedin this behavior,againsttheirungulateprey,who did not.50This mode, which we propose to refer to as the "Progressive

44. P. Medawar,"DoesEthology ThrowAny Lighton HumanBehaviour?" n Bateson and Hinde,ed., GrowingPoints in Ethology, 503.45. C. Packerand A. E. Pusey, "DividedWe Fall:Cooperationamong Lions,"ScientificAmerican

276:5 (1997), 52-61.46. T. M. Caroand M. D. Hauser,"IsThereTeaching n NonhumanAnimals?"QuarterlyReviewof Biology67:2 (1992), 151-174.47. C. Blakemore, "How the EnvironmentHelps to Build the Brain,"in Mind, Brain, and theEnvironment, d. B. Cartledge(Oxford, 1998), 28-56; H. J. Chiel and R. D. Beer, "The Brain Has a

Body: Adaptive BehaviorEmerges from Interactionsof Nervous System, Body and Environment,"Trends in Neurosciences 20:12 (1997), 553-557; J. L. Elman et al., Rethinking Innateness: AConnectionistPerspective on Development Cambridge,Mass., 1996).48. D. R. Griffin,AnimalThinking Cambridge,Mass., 1984).49. Caro andHauser,"Is ThereTeaching n NonhumanAnimals," 153.

50. H. J. Jerison,Evolutionof the Brain and Intelligence(New York, 1973).


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A BRIEFHISTORY FEVOLUTION 21

DNA ~Phenotype.l~~~~~~~~~~~~~~~~~~

t;-ff:00:!::;t-(kom;:-:;


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22 ALBERTF. H. NACCACHEspecies had existed for eons.57However, slowermaturation nd greater ongevi-ty enabledand propelledan increase in intergenerationalnteraction.This devel-opment,which,on the basisof the evidenceat hand, took place only amongsomefamilies of elephants,whales,58andhominoids, led to a radicalextensionof the"pre-humananguage"communicationsystem. Projectingback from its devel-oped state,this extension is seen to have the following characteristics:

1. Its content,thoughstill embodiedin individualphenotypesanddependingon their direct interactions or its transmission, s sustainedby a social groupasa whole, and notby an individualphenotype.It has individualcarriers,butsinceit can outlive eachone, it has a certainautonomy.

2. It can carryemotional, behavioral,and/or cognitive informationover amuch longertime span thanan individual ife, andacross greatsocial distances,giving rise to what is conservativelyreferred o as culture.59

3. The body of knowledgethatit carriessubmitsto differentcognitive, com-municative,and accumulative imitationsthanto those imposed on the knowl-edge of individualphenotypes-among other things,its intrinsicdevelopment s"Lamarckian."60

4. Finally,it affectsthe life-cycle processesbecauseit enhancesand amplifiesparentalbehavioral nterventions n the organicand behavioraldevelopmentofthe offspringphenotype.

Organismshad long shared,even multigenerationally,he physical extensionof theirphenotypes,61uch as a beaver's dam, butwhatwe have hereis qualita-tively different. How mightthis developmenthave come about? Extendedlife-spansin a tightlyknit small groupcreatedthe opportunity or elders to keep ondoingwhat theyhadbeen doing, only now to teach not theirchildren,butgrand-children. Greatapes of six million years ago had the neuralprerequisite o usetheir shared prelinguistic"grammar"of action to intentionally communicateinformation through voluntary oro-facial or gestural signals.62 The increased

57. N. K. Humphrey,"The Social Functionof Intellect,"in Bateson and Hinde, ed., GrowingPoints in Ethology,303-517; N. Rescher,A Useful Inheritance:EvolutionaryAspects of the Theoryof Knowledge(London, 1990).

58. D. Reiss, "Cognitionand Communication n Dolphins: A Question of Consciousness,"inHameroff,ed., Toward Scienceof Consciousness I, 551-560; H. Whitehead,"Cultural election andGeneticDiversityin MatrilinealWhales,"Science 282 (1998), 1708-1711; P. Mackenzie,"ElephantInformationRepository,"(1999).59. C. Boesch, "The Emergence of Cultures among Wild Chimpanzees," n Runciman, ed.,Evolutionof Social BehaviourPatterns,251-268; W. C. McGrew,"Culturen NonhumanPrimates?"Annual Reviewof Anthropology27 (1998), 301-328; A. Whitenet al., "Cultures n Chimpanzees,"Nature 399 (1999), 682-685.

60. Or rather"Spencerian"; ee M. Ruse, TakingDarwin Seriously:A NaturalisticApproachtoPhilosophy(London, 1986), 125.

61. Dawkins,TheExtendedPhenotype.62. Two recent studies make this point: G. Rizzolatti and M. A. Arbib, "Languagewithin Our

Grasp,"Trends n Neurosciences21 (1998), 188-194;R. Worden,"The Evolutionof LanguagefromSocial Intelligence," n J. R. Hurfordet al., Approaches to the Evolution of Language: Social andCognitiveBases (Cambridge,Eng., 1998). See also M. Jeannerodet al., "GraspingObjects:TheCortical Mechanismsof VisuomotorTransformation," rends n Neurosciences 18 (1995), 314-320;F. Aboitiz and V. Ricardo Garcia, "TheEvolutionaryOriginof the LanguageAreas in the HumanBrain:A NeuroanatomicalPerspective,"BrainResearchReviews25 (1997), 393.


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A BRIEF HISTORYOF EVOLUTION 23potential for multigenerational ontacts opened up the possibilityfor vigoroussenior females to have more descendantsboth by contributing o the survival oftheir weaned grandchildren, nd by freeing their daughters o become pregnantsooner.63Such a context would provide the selective pressurefor language toevolve.

Prior o the emergence of this extension in communication,behavioralpheno-types had remainedbound to one organism.Withit, temporallyandgeographi-cally distantmembersof a social groupcould affect, throughphenotypical raitsthey had acquired, he life-cycle setupbetween any parentandoffspringin thegroup.64We refer to this extension as "social memory,"a more descriptivetermthan "culture,"or "collective,"or "group memory"and one less loaded than"memes,"65r "World ,"66 and propose to call the MoEto which it gave risethe"socioculturalMoE."This mode is representedn Figure 5, in which the exten-sion in communication s depicted by a verticalbox of the same "kind"as thatofthe phenotypes, and independentof, butconnecting with both, parent'sand off-spring'sphenotypes.

. ......~ ~~~~~~~~~~~~~~'"-.''.','i.-.000. 1 0 0 ; -- 0 -- ~ ~~~~~~~~~~~~~~~~~..... ... ...- . ...~X God ;.g A_!-;-n,#

~~~~~~~~.,.................................. f.0. --,;/ 4 .. 44444444444444;4....... .......3i~~~~~~~~~~~... ,g'S>...........z. : ,.S.., ...A .> . ........ ' ' : i

armi ~~~~~N'' '---' CEn-;o.

Figure 5. Life-cycle setupfor the SocioculturalMode of Evolution(Hominoids,Whales, Elephants)5 million years ago -

A comparison of the proboscides'and hominoids'phylogenetictrees placesthe onset of the socioculturalMoE sometimes before six million years ago, thetime of the last pongidandhominidcommon ancestor.Its neuroanatomicalor-relatewouldbe, amongthehominoids,the increase n brainsize displayedby thegreat apes over thatof the baboons.67Similar increases are found in the ele-phants'fossil record.68

63. K. Hawkeset al., "Grandmothering,Menopause,and theEvolutionof HumanLife Histories,"Proceedings of the National Academyof Sciences USA 95 (1998), 1336-1339; B. Wood and A.Brooks, "WeAre What We Ate,"Nature 400 (1999), 219-220.

64. C. Boesch and M. Tomasello, "Chimpanzeeand Human Cultures,"CurrentAnthropology39(1998), 591-614.

65. R. Dawkins, The SelfishGene (Oxford, 1976).66. K. Popper,ObjectiveKnowledge:An EvolutionaryApproach Oxford, 1972).67. Jerison,Evolutionof the Brain and Intelligence, 394.68. Ibid.,342-351. Thewhales anddolphinsmighthave achieved theirmodernenlargedbrainsear-

lier, in Miocene times, about 15-20 million years ago (ibid., 348).


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24 ALBERTF H. NACCACHEPartly because of the contingent aspect of its accumulativemechanism,and

partly because of structural auses, such as differentecological adaptations,hesocioculturalMoE has not affected to the same extent all species of the threefamilies. Still, modern-day elephants and many species of whales have beengreatlyempowered by it, today displaying the most advanced of the prehumancommunication ystems, and being the only nonhumanbeings for which there isevidence of reverencefor dead family members.

Among otherbehaviorsenhancedby the socioculturalMoEis tool use, thatis,using naturalobjects lying around n orderto help performan action. This is sobecause social memory facilitates the acquisition and transmission of suchbehavior, as illustratedby the elephants'developed aptitudefor it,69 n spite oftheirmorphological imitations,and the streamlineddolphins' manipulative en-dencies.70

As for thehominoids' ineage, it enjoyeda most favorablecontingentpreadap-tation. Its ancestorshad made,some fifteenmillion years ago, the transition romlife in the treesto life on the ground.71Then, some five to six million yearsago,some of its species72had developed a bipedalstance.73The progressivefreeingof the hands74 volved independentlyof the socioculturalMoE, but in conjunc-tion with it, was decisive in shapingthe furtherevolutionof the lineage.

Culturallypropelledtool use and manufactureamongthe hominoids evolvedfrom prepared wigs to the two-and-a-half-millionyear-old Oldowan choppersrecovered in Gona, Ethiopia. This development must have been gradual.Chimpanzeesnot only use tools, but display rudimentaryool preparation,hefirst stage of industry,75 nd the earliest lithic industry,achieved some two mil-lion yearsafter the freeing of the hominoids'hands,was still within the compe-tence of an"apeadaptivegrade."76

With lithic culture,the hominoidphenotypehad acquireda power-enhancingand durableextrasomatic xtensionthatcouldbe sharedacrossgenerations.Theincorporationof this extrasomatic extension to the life-cycle setup greatlyincreased the potentialability of the hominoid phenotypeto interactwith itsenvironment,and thus led to the emergenceof a secondstagein the sociocultur-al MoE.This secondstageis representedn Figure6, in whichthe solid line link-ing the parentandoffspring phenotypesto the social memory extension standsfor this sharedextrasomaticextension of the phenotype.

69. Mackenzie, "Elephant nformationRepository."70. Reiss, "CognitionandCommunicationn Dolphins."71. B. R. Benefit and M. L. McCrossin, "Miocene Hominoids and Hominid Origins," AnnualReview of Anthropology24 (1995), 237-256.72. B. WoodandM. Collard,"TheHumanGenus,"Science 284 (1999), 65-71;P.V.Tobias, "Ape-like Australopithecus fter Seventy Years:Was it a Hominid?,"Journalof the Royal Anthropological

Institute4 (1998), 283-308.73. J. L. Bradshaw,HumanEvolution:A NeuropsychologicalPerspective (Hove, Eng., 1997) 26-

32.74. R. L. Susman,"Fossil EvidenceforEarlyHominidToolUse,"Science 265 (1994), 1570-1573.75. Bradshaw,HumanEvolution, 123-143; Gibson andIngold, ed., Tools, Languageand Cogni-

tion;see also note59.76. T.Wynnand W. C. McGrew,"AnApe'sView of theOldowan,"Man(n.s.) 24 (1991), 383-398.


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ABRIEFHISTORY FEVOLUTION 25

(Homo).6 millin L0year!ao

~~~~~~~~~~~~~~~~~......

Thegworking ife-yl euoheextrasomatically nhancedcoutrlME"wt t"Lamarekianly" erminatingsocial memory and its extrasomaticextensions,favored augmented and intensified parental behavioral interventionsin theorganic and behavioral growth of the offspring phenotypes. The effects on theevolution of the human ineage of these interventionswere suchthatsome con-sider homo sapiens to be a self-domesticated species.The morphologicalcorrelateof this second stage in the socioculturalMoEcould have happenedeitherwith the increase in encephalizationof the australo-pithecinesover thatof the pongids,7 or with the further ncreasein brainsizeregisteredwith the emergenceof the firstspecies of the genus homo.79We can-not be moreprecisesince hominid brain evolutioncontinued withoutany majorreorganizationduringall thatperiod,80and"thedetailsof humanbrainevolutionare still largely obscure."81After five million years and more of the workings of the sociocultural MoE,during the last half of which the extrasomatic extension played its enhancingrole, some artifacts were intentionally made to carry a specific reference to asocial memory sharedby a group, that is, to carry a symbolic message. Theappearanceof artifactsspeciallymade to carry elementsof social memoryush-eredin theemergenceof a distinctnew extension of the hominidlife-cycle setupbecause:

1. Even thoughthe artifactsstill needed to be "read"or activated n, or by, anindividual,the transmissionof theirmessages no longerrequiredchronologicalor social contiguity between their makers and their readersor carriers.This

77. K. Lorenz,Essais sur le comportement nimal et humain(Paris, 1970), 367.78. Jerison,Evolutionof theBrain and Intelligence,389.79. Wood andCollard,"The HumanGenus."80. H. Jerison, "Fossil Evidence of the Evolution of the Human Brain," Annual Review of

Anthropology4 (1975), 42.81. T. W.Deacon, "RethinkingMammalianBrainEvolution,"AmericanZoologist30 (1990), 698;see also H. P. Killackey, "Evolution of the Human Brain: A NeuroanatornicalPerspective," inGazzaniga,ed., TheCognitiveNeurosciences, 1243-1253.


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26 ALBERTF. H. NACCACHEmeant that the chronologicalandsocial reach of social memory was considerablyextended;82

2. Being inorganically supported,and thereforepotentially durable,the sym-bolically loaded artifacts ent social memory a semi-autonomy rom humanphe-notypes;

3. Groups sharingthese artifactshad the cognitive, communicative,and accu-mulative capabilities of theirphenotypes radically augmented;

4. The aggregationof symbol-bearingartifacts,or "exosomatic social memo-ry," interacts and has functionalrelationshipswith the previously establishedintergenerational ocial memory.83

It is difficult to pinpoint the neuroanatomical ubstrateof symbolic behaviorandtheexosomatic socialmemory.Thefossil record s still quite incomplete,andthereis no consensus yet on how to disentanglethe branchesof our family treeand confidently correlate gross neuroanatomyand behavior among the varioushomo sapiens species.84 Fossil brain endocastsprovide only minimal informa-tion,85and even assumingthat we were able to define the cognitive processesunderlying heintentionalproductionof symbolic artifacts,86 e would still needto correlate these processes with aspects of brain architecture.This last is adaunting ask, judging by the extremely complex picturewe alreadyhave of themuch simpler anatomicalorganizationof the macaque visual system.87For thetime being we can only glimpse the emerging pictureof cerebralactivitiesrelat-ed to languageandcognition.88And finally,we shouldnot forgetthatthe human

82. R. Whallon, "Elements of CulturalChange in the LaterPalaeolithic," n TheHuman Revo-lution:BehaviouralandBiological Perspectiveson the Origins of ModernHumans,ed. P.MellarsandC. Stringer Edinburgh,1989), 444.

83. T. F. H. Allen and T. B. Starr,Hierarchy: Perspectivesfor Ecological Complexity Chicago,1982), 218.

84. C. L. Brace,"BioculturalnteractionndtheMechanism f Mosaic Evolutionn theEmergence f'Modem' Morphology,"AmericanAnthropology 7 (1995), 711-721; F. D'Errico et al., "NeanderthalAcculturationn WesternEurope?"CurrentAnthropology9, supplement1998), 1-44;A. Mann,"ModernHumanOrigins:Evidence from the Near East," Paleorient21 (1995), 35-46; P. Mellars et al., 'TheNeanderthal roblemContinued," urrentAnthropology0 (1999),341-346;J.H.Relethford, Genetics fModem HumanOriginsandDiversity,"AnnualReviewof Anthropology 7 (1998); J. J. Shea,"NeandertalandEarlyModem HumanBehavioralVariability," urrentAnthrmpology9 supplement 1998), 45-78; M.C. Stiner,"ModernHumanOrigins-Faunal Perspectives," nnualReviewof Anthropology2 (1993);I.Tattersall, Outof AfricaAgain ... andAgain?"ScientificAmerican276, no.4 (1997), 60-67;E. Trinkaus,"NearEasternLateArchaicHumans,"Palkorient 1 (1995), 9-24; B. Vandermeersch,Leroledu Levantdans1'6volution e l'humanit6 uPlistocene Superieur,"aMorient 1 (1995),25-34.85. R. L. Holloway,"Exploring he Dorsal Surfaceof HominoidBrainEndocastsby StereoplotterandDiscriminantAnalysis," n TheEmergenceof Man, ed. J.Z.Younget al. (London, 1981), 155-166..

86. P. A. Mellars,"TechnologicalChanges across the Middle-UpperPalaeolithicTransition:Eco-nomic, Social and CognitivePerspectives,"n Mellarsand Stringer, d., TheHumanRevolution, 38-365.87. D. C. Van Essen andE. A. Deyoe, "ConcurrentProcessing in the PrimateVisual Cortex," n

Gazzaniga, ed., TheCognitiveNeurosciences, 388.88. T. Beardsley,"TheMachineryof Thought,"ScientificAmerican277, no. 8 (1997), 78-83; G.D. Jacksonand J. S. Duncan, MRINeuroanatomy:A New Angle on the Brain (New York, 1996); J. J.

Jaegeret al., "APositronEmissionTomographicStudyof Regular andIrregularVerbMorphology nEnglish," Language 72 (1996), 451-497; C. J. Mummeryet al., "Generating Tiger' as an AnimalNameoraWordBeginningwith T:Differencesin BrainActivation,"Proceedings of theRoyal Societyof London B 263 (1996), 989-995; C. J. Price et al., "The Neural Regions Sustaining ObjectRecognitionandNaming"Proceedings of the Royal Society of LondonB 263 (1996), 1501-1507.


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A BRIEFHISTORYOF EVOLUTION 27brainonly sets generallimits to the humanbehavioralphenotype and does notdictate particularmplementations,which aresocioculturallydetermined.89

Therefore, n orderto determine he date of onsetof the exosomaticmemory,we have to find the oldest artifact hat could reliablybe considered ntentionallymade to carry a symbolic message, the first artifactclearly producedprimarilyfor its symbolic function or value. Clearly,many of the human ntellectualcapa-bilities, includingthe use of symbols, predatewriting,90 utby how much?Whatis the oldest symbolic artifact?Is it the 50,000-year-old "depictive mage,"91 rthe 100,000-year-old "exquisite nonutilitarianoval plaque,"92 r the 250,000-year-old"figurine"?93 rmight it be some artifact hat appears o be utilitarian,such as theconsummatelycrafted400,000-year-oldwooden spearsfoundrecent-ly near Hanover?The use of these powerful weapons must have been"symboli-cally loaded," but it is also arguable that the extraordinary are and attentionneeded to produce artifacts having such magical properties could only beexpended n the context of a successionof symbolic acts.This is so because man-ufacturing echnologyhadto be coaxed from a magical contact with the materi-als andtheirproperties,andnot, like today,deducedfrom a bodyof scientific andtechnological knowledge.

If some 400,000 years ago, artifacts ntentionallycarryingsymbols wereman-ufacturedwith suchcare,their firstappearance ould well be correlatedwith theemergenceof archaic homosapiens, and the neuralcorrelateof the exosomaticsocial memorywould be the brainenlargementassociatedwith it.

Ourperceptionof the worldis so deeplyembedded n anddependenton sym-bolic systems thatit is hard to realizethatthese, like all emergingphenomena,must have followed a growthcurve,and thattheymusthavehad, therefore,veryhumble beginnings. Humble beginnings they had, but levered on top of the"Lamarckian"ocioculturalMoE, the growthrate was explosive. So explosivethat it is perceivedlike a succession of nested,ever-accelerating evolutions:

1. The UpperPaleolithiccognitiverevolutionsome 30,000 years ago;2. Thesymbols'revolution f theLevantineEpipaleolithic hatushered he first

permanent ettlementsand thenagriculture ome 14,000 years ago;943. The urban revolution5,000 years ago;4. The scientificrevolution500 years ago;5. And now a burstingrevolutionso far-reachinghat t is ushering n the emer-

gence of a furtherMoE rightunderoureyes, a mode thatI will attempt o char-acterize n the next section.89. Rescher,A Useful Inheritance,124.90. See amongmanyothers:R. G. Bednarik,"Concept-mediatedMarking n theLowerPaleolithic,"

CurrentAnthropology36 (1995), 605-634; A. Belfer-Cohen,and N. Goren-Inbar,"CognitionandCommunicationn the LevantineLower Palaeolitthic"WorldArchaeology26 (1994), 144-157.91. A. Marshack, "A Middle Paleolithic Symbolic Composition from the Golan Heights: TheEarliest Known Depictive Image,"CurrentAnthropology37 (1996), 357-364.

92. Idem.93. A. Marshack,"TheBerekhatRam Figurine:A Late AcheulianCarvingfrom theMiddle East,"

Antiquity71 (1997).94. J. Cauvin,Naissance des divinitis, Naissance de agriculture: La Revolutiondes Symbolesau

Njolithique (Paris, 1997).


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28 ALBERTF. H. NACCACHEBut before doing that, I still have to propose a name for the MoE that has

definedhumanhistory,and which is characterizedby the presence in the humanlife-cycle setup of an inorganicallysupported,exosomatic social memory. Wecould call it the "exosomaticsocioculturalMoE," but let us try to find a moresuggestive name. We note that the workings of this mode have allowed the fol-lowing modifications of homo sapiens' life-cycle setup:

1. The progressive elimination of the causes of "natural election" in humanpopulations(throughhygiene, medicine, and populationmovements);

2. The growing potential to control thegenome's reproduction upto geneticengineering);

3. The furtheramplificationof all behavioral nterventions n the organic andbehavioral developmentof offspring phenotype (throughtechnology and engi-neering).

These modificationshave not yet run theirfull course, and all three might notbe traceableall the way back to the onset time of this mode.However, theyhavesufficientlyalteredthe underlyingbiological mechanisms of the life-cycle setupto be consideredcharacteristic f this mode. All threemodificationshave comeaboutas theresult of unskilledand/orexperimental epairor adjustmentmadebyhomo sapiens to basic biological processes.That is, all threeare cases of "tin-kering,"which is why I propose to refer to this mode as the "tinkeringMoE."95

Genorne~ - DNA 0Phenotype0!7S;

GenomeN Phentotype..is~~~~~~~~~~~~~~~~~~*i

Figure7. Life-cycle setupfor theTinkeringMode of Evolution(Symbolicrepresentation) 00,000 years ago -This mode is represented n Figure7, in which the "exosomaticsocial memory"is depicted emergingfromandinteractingwith the "social memory."

Therehas been suchan increaseandso muchrefiningof knowledgecarriedbythe exosomatic social memory,so muchprogress n its inorganicsupport, hat itmight soon achieve full autonomy.96n the not-so-distantfuture, inorganicallyembodied nformation ould becomeendogenouslyactivatedandauto-reproduceitself. Such a development might be engineered,97 ollowing the "principleof

95. Tinkering s more appropriately pplied to shortsightedhuman voluntary ntervention han toevolution'srandomways, as in Jacob,"Evolutionand Tinkering."

96. N. Wiener,God & Golem,Inc. (Cambridge,Mass, 1964).97. 0. Sporns,"NeuralModels of PerceptionandBehavior," n 1993 Lectures n ComplexSystems,ed. L. Nadel and D. L. Stein (New York, 1993).


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A BRIEF HISTORYOF EVOLUTION 29organizational nvariance,"98r it might happen"spontaneously," ropelledbythe ever-growing interactionwith the environmentof complex computationalsystems endowed with perceptual and effectual means.99Charles Babbage's"Analytical Engine" and the "ABC" (Atanasoff-BerryComputer)would havebeen fast flowering seeds....

I propose to refer to this still-emerging MoE as the "parabiologicalMoE"(para-being less limiting and committing than exo-, extra-, trans-, or meta-). Iwill not presume to define the setup of this nascentMoE, but simply note inFigure8 a possible basic configuration. t is characterized y a fully autonomousinorganicmemory,as well as by a potentialoutcomeof an actual trend,whichisthejettisoningof the organic and behavioralparticipationof parentphenotypesin the growth of the next generationphenotype.I will not venturehere to guessatwhattherelationshipbetweentheorganicandinorganicconsciousnesswill be,if, or ratherwhenthe latterwill emerge.

Genome DNA Ph~~~~~~~~enotype,~

Figure . Life-cycle etup ortheParabiological odeof Evolution(Babbage) 50yearsago

IIII have now provided summarydefinitions of the eight hierarchicallynestedmodes of evolutionthat,accordingto the present proposal,have progressivelyemergedto governthe evolutionof ourlineage fromprimitivecyanobacteria o-today'shuman societies. Many issues, such as the specific operationof themodes, theirprocessesand ratesof development,the natureof theiremergenceor coalescence,or the cumulativenessbetweenmodes,have not even been men-tioned. Yet, what I have discussed should be suggestive of how the presentframeworkachieves the aim it was designed for, that is, separating he humanbehavioralspectrumalongthe nature/nurtureontinuum.Let us analyzeanarbi-trarilyselected behavior,here the "biological" predispositionof young adultmales "tohomicide relative bothto oldermalesandto coeval females acrossthe

98. D. J. Chalmers,"ThePuzzle of Conscious Experience,"ScientificAmerican273, no. 6 (1995),80-86.

99. Hameroff,et al., ed., Towarda Science of ConsciousnessI.


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30 ALBERTF. H. NACCACHErange of human societies."'100he resulting spectrum s presented as a series ofvignettes describingan imaginaryoccurrenceof such a behavior:10'

1. His bout of hay-fevermakeshim sneeze, an immunological process hark-ing backto the basic MoE;2. His perception of a threat to his physiological needs and values triggersintenseneuronalactivity across his limbic-brain temsystem, throughprocesseslaid down underthe reptilianMoE;

3. He takesmentalnoteof histerritoryhathasjustbeen invadedby anothermem-ber of his species,usingprocesseselaborated nder he archaicmammalianMoE;

4. A quick side look shows him thathis brothersand cousins havejoined him,in a social strategydevisedunderthe progressivemammalianMoE;

5. He burstsforth, havingto maintainhis inheritedsocial rank,a developmentacquiredunderthe multigenerationalocioculturalMoE;

6. He is alternatively hrustingandbrandishinghis spearwhile charging, n theways of his tribe, developedunderthe extrasomaticallyenhancedsocioculturalMoE;

7. Onhis spearareengraved he symbolsof a potentincantation hat will givehim victory overhis enemy,if he canjust hit the latter's backwithoutinflictingotherharm,as decided underthe tinkeringMoE;8. He stumbles and falls. The inorganicconsciousness lets out a virtualsigh,and slightly modifies the parametersbefore replayingthe scene, all the whilethinkingthat it was much more fun when there were fully functionalhumans toplay with.

An incidentaladvantageof this series of vignettesis that it facilitatescompar-ison withcompetingframeworks, uch as the following two prominentand well-documented recent proposals.102Maynard Smith and Szathmairypropose aframeworkof eight "major volutionary ransitions"defining the following nine"stages":103

1. The originof simple autocatalytic ystemswith limited heredity;2. The originof polynucleotide-likemolecules,providingunlimitedheredity;3. Theoriginof thegenetic code in the context of the RNAworld, before trans-

lation;4. The originof translationand encodedprotein synthesis;5. Thereplacementof RNA by DNA as the genetic code;6. The emergenceof hereditaryregulativestates in prokaryotesand simple

eukaryotes;

100. W. G. Runciman,"Introduction,"n Runciman,ed., Evolutionof Social Behaviour Patterns.101. Caricature'swide information bandwidthwill hopefully excuse the whimsicalityof thesevignettes.102. F. Spier's frameworkpresented in The Structureof Big History: From the Big Bang untilToday Amsterdam,1996), "cannotcarry the load placed on it," as pointed out by B. Mazlishin his

review, "Big Questions?Big History?"History and Theory38 (1999), 244.103. J. MaynardSmith and E. Szathmdry,TheMajor Transitions n Evolution(Oxford, 1995); E.SzathmdryandJ. MaynardSmith, "TheMajorEvolutionaryTransitions,"Nature 374 (1995), 227-232.


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A BRIEF HISTORYOF EVOLUTION 317. The evolution of epigenetic inheritancewith unlimitedheredity:the emer-

gence of animals,plants and fungi;8. The emergenceof proto-languagen Homo erectus-a cultural nheritance

system with limited potential;9. The emergence of human language with a universalgrammarand unlimit-

ed semanticrepresentation.Though both frameworksrange from organic chemistry to human societies,

and thoughthe two approaches harethe same axiomatic dea that there are "lev-els of organization, and hence levels of selection,"104Maynard Smith andSzathmairy's im is not the same as that of our framework.With its six succes-sive "stages"where ourshas one "basic MoE,"theirframework ocuses on theanalysisof the emergenceof biological evolution, and does not reveala princi-ple of continuity n the integrationof human evolution. In their framework hisintegrationseems almost arbitrary, ased on the analogy that "changein lan-guage wherebyinformation s transmittedand in the physical medium thatcar-ries thatlanguage"105s involved bothin the transition rom RNA to DNA andinthe origin of specifically human societies.

Foley proposesa "phylogeneticand chronological context for human socialevolution"thatidentifies the eight "key 'events' and time periods":1061. 35 million years (35Myr):the anthropoidsand the originsof society;

2. 25Myr:finite social space andthe kinshipas the basis for social organiza-tion;

3. 15Myr:catarrhine ocial phylogenyand the evolutionof male kin-bonding;4. 5Myr:savannasocioecology;5. 2Myr: expensive [sic] offspring andthe socioecologicalbasis of encephal-

ization;6. 300,000 (300Kyr):the 1000 grambrain andevolutionof humanlife histo-

ry strategy;7. lOOKyr: ispersal,group size, andterritoriality;8. 30Kyr: demographyand the agricultural evolution.Foley's timetablestartswith our fourthMoE andencompassesevolutiononly

since the advancedmammaliangrade.The two frameworksareroughlyin stepforFoley's timeperiods4, 5, and6, whichcorrespondo ourfifth, sixth,and sev-enthMoE,butFoley is more detailed at the two extremes. The difference stemsfrom the fact thatFoley's phylogeneticcontext is aimed at showing "where andwhen did the benefitsof particularhuman traitsexceed the costs andprovideaselective advantage,"07 while our frameworks designedto classify the mecha-nisms responsiblefor "particular umantraits."

104. MaynardSmith andSzathmdry,TheMajorTransitionsn Evolution,12.105. Idem.106. R. A. Foley, "AnEvolutionaryandChronologicalFramework or Human Social Behaviour,"in Runciman,ed., Evolution of Social BehaviourPatterns, 95; Foley, Humans before Humanity:An

EvolutionaryPerspective (Oxford, 1995). I follow here the article and not the slightly differentbook.107. Foley, Humans before Humanity,207.


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32 ALBERTF. H. NACCACHEIf we now comparethe three frameworks, t should be clear that they arenot

methodologically exclusive of each other. By focusing upon the origins of bio-logical reproduction,MaynardSmith and Szathmarywere able to uncoverthesuccessive mechanismsand modes of evolution that bridged, through replace-mentor addition,chemistryandbiology. By focusing uponhominid social evo-lution, Foley was ableto uncover specific demographic,biological, environmen-tal, and social contexts that have molded it. By taking the overall perspective,and basing it systematicallyupon the principleof reproduction,we hope to haveachieved a prismfor the study of human behavior that,while not yet properlypolished,will be judgedworthy of revision andimprovement.

Lebanese UniversityBeirut

naccache-history of evolution

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