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Multilevel Selection, Meaning Systems, and the Evolution of Language David Sloan Wilson Departments of Biology and Anthropology Binghamton University Binghamton NY 13902 [email protected] The Three C’s of Human Distinctiveness • Cognition • Culture • Cooperation Each is highly distinctive compared to other species, not unique. Cognition • Our distinctive capacity for symbolic thought, including but not restricted to spoken language. Culture • Our distinctive capacity to transmit learned information in a cumulative fashion. Cooperation • Our distinctive capacity to cooperate in large groups of unrelated individuals. Challenge How did these three capacities evolve in relation to each other? One hypothesis •!Our distinctive cognitive ability came first. • “Theory of mind” •!Enabled more widespread cooperation and culture. •!e.g., Michael Tomasello (2001) “Tomasello thinks that all of the many unique characteristics of humans are elaborations of one trait that arises in human infants at about nine months of age: the ability to understand other people as intentional agents.” Another hypothesis •!Our distinctive cooperative ability came first. • The other two Cs are fundamentally cooperative activities and required a shift in the general capacity for cooperation to evolve. •!e.g., Michael Tomasello (2008) “Tomasello argues that human cooperative communication rests on a psychological infrastructure of shared intentionality (joint attention, common ground), evolved originally for collaboration and culture more generally. The basic motives of the infrastructure are helping and sharing. On its way to becoming the prevailing view My Challenge: Provide the evolutionary background for the “cooperation came first” hypothesis •!Multilevel selection theory • Major transitions of evolution •!Human evolution as a major transition • Language and its precursors •!Taking concept of the group super-organism seriously •!The evolution of “meaning systems” • The adaptedness of meaning systems. •!An example of two modern meaning systems as the cultural equivalent of biological species. Multilevel Selection Theory • Individual-level adaptations are locally advantageous. • Sharper teeth • Thicker fur • More cryptic coloration Multilevel Selection Theory • Social adaptations tend to be locally disadvantageous. • Altruism • Public good provision • Most behaviors that are “for the good of the group” The Problem •!How can “for the good of the group” traits evolve when they are locally disadvantageous? The (Partial) Solution • Because “for the good of the group” traits are advantageous at a larger scale. • Groups whose members behave “for the good of the group” survive and reproduce better than groups whose members are self-serving. • The solution is only partial because positive between-group selection must be strong enough to prevail against negative within-group selection. The One-Foot Version of Sociobiology • Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary. • The long version: • • Wilson, D. S., and E. O. Wilson, (2007). Rethinking the theoretical foundation of sociobiology: Quarterly Review of Biology, v. 82, p. 327-348. Wilson, D. S., & Wilson, E. O. (2008). Evolution "For the Good of the Group". American Scientist, 96, 380-389. Truth and Reconciliation for Group Selection • T&R is a process of resolving bitter political conflict • Can be used to resolve longstanding scientific controversy • 19-part series on ScienceBlogs site (compiled version on my website) Truth and Reconciliation for Group Selection • Not a matter of finding one or two cases of group selection • A perspective change • All evolutionary theories of social behavior include the logic of multilevel selection Major Evolutionary Transitions • The balance between levels of selection is not static but can itself evolve. • When between-group selection dominates within-group selection, the group becomes so cooperative that it becomes a higher-level organism. • Another major pathway of evolution, in addition to mutational change. Timeline • 1970’s: Lynn Margulis proposes that nucleated cells are symbiotic associations of bacterial cells. • 1990’s: John Maynard Smith and Eors Szathmary generalize the concept to include multiple major transitions. • Origin of life • First bacterial cells • Nucleated cells •!Multicellular organisms •!Social insect colonies • Human evolution Hallmarks of a Major Transition • Rare event in the history of life. It’s not easy for betweengroup selection to dominate within-group selection. • Momentous consequences when it occurs. New higherlevel organism becomes ecologically dominant. • Transition is never complete. Selfish elements that spread by within-group selection are only suppressed, not entirely eliminated. • True organisms, whose members behave 100% for the common good, do not exist. Human Evolution as a Major Transition • Rare event in the history of life. It’s not easy for betweengroup selection to dominate within-group selection. Only once among primates. • Momentous consequences when it occurs. New higherlevel organism becomes ecological dominant. Worldwide ecological dominance. • Transition is never complete. Selfish elements that spread by within-group selection are only suppressed, not entirely eliminated. Thinking of human groups as like organisms does not deny the existence of conflict within groups. Stone throwing: The first human adaptation? A major transition requires the suppression of deviance within groups, which needn’t require an advance in cognitive ability Hunter-gatherer egalitarianism as a form of reverse dominance On its way to becoming the prevailing view A tipping point in early human evolution Within-group selection Chimp-like ancestors Between-group selection Human-like ancestors Group-level adaptations that preceded language • Cooperative eyes • Shared awareness (Pointing) • Laughter • Dance • Music • Visual art • These and other adaptations let to the ability to transmit learned behaviors in a cumulative fashion, resulting in a process of rapid cultural evolution. Cultures as Species Taking the super-organism concept seriously • Long history • New against the background of individualism, which has dominated intellectual thought for the last half century. Old and New • Toqueville: “The human township is the only unit so perfectly natural that it seems to constitute itself. “ • Modern translation: We are genetically adapted to function adaptively as groups at a small scale, although culturally evolved mechanisms are required to function adaptively at a larger scale (e.g., USA, France) Old and New • Durkheim: “Social life…in every aspect and throughout its history, is possible only thanks to a vast body of symbolism.” • Modern translation: Humans are completely reliant upon culturally evolved meaning systems to function in their daily lives. • Genetic evolution created the capacity to make meaning systems. • Highly sophisticated, multi-trait. • Evolutionary Social Constructivism. Meaning Systems • Receives environmental information as input. •!Results in action as output. •!Includes any mechanism that contributes to this transformation (e.g., beliefs, practices, ritual…). • Definition of a meaning system similar to the definition of a brain. The Adaptedness of Meaning Systems • Linguists might regard the adaptedness of language as a recalcitrant problem. •!The adaptedness of meaning systems can be straightforwardly settled in terms of what belief systems cause people to do in relation to their environments. •!The same methodological toolkit used to study genetically evolved adaptations. Six major hypotheses that evolutionists use to study all traits RELIGION AS AN ADAPTATION RELIGION AS NONADAPTIVE Group-level adaptation (benefits groups, Adaptive in small groups of compared to other groups) individuals but not in related modern social environments. Individual-level adaptation (benefits Byproduct of t raits that are adaptive in individuals, compared to other individuals non-religious contexts. within the same group) Cultural parasite (benefits cultural traits Neutral traits (drift) without regard to the welfare of human individuals or groups) A Contemporary Example of Cultures as Species •!Conservatism and liberalism as adaptations to environments that differ in existential security. •! Sacred and Secular by P. Norris and R. Inglehart. •! “Liberal and Conservative Protestant Denominations as Different Socioecological strategies” (I. Storm and D.S. Wilson, Human Nature) What Is Existential Security? •! The safety and stability of one’s environment, at least as subjectively perceived. •! Secure environments enable individuals and societies to invest in their development, permit experimentation without dire consequences, and decrease reliance on tradition. The niche for liberalism, in both religious and nonreligious formulations. What Is Existential Security? • !Insecure environments prevent individuals and societies from investing in their development, often require strong collective action and reliance on tradition. The niche for conservatism. • This is a crude dichotomy; in reality there a multiple forms of liberalism and conservatism, as we would expect in a multiple-niche environment. Religion as software that programs individuals to behave in different ways (Storm and Wilson 2009) • • • • •! • Large empirical data set Everyone is American Everyone is a teenager Everyone comes from the same major religious tradition. In these respects, they are culturally uniform. But some are Episcopalians and others are Pentecostals (for example). • This cultural difference creates astonishing differences in how the teenagers respond to their environments--what in evolutionary terms we would call their norms of reaction. Worldwide variation in religiosity My Challenge: Provide the evolutionary background for the “cooperation came first” hypothesis •!Multilevel selection theory • Major transitions of evolution •!Human evolution as a major transition • Language and its precursors •!Taking concept of the group super-organism seriously •!The evolution of “meaning systems” • The adaptedness of meaning systems. •!An example of two modern meaning systems as the cultural equivalent of biological species. Your Challenge: Implications for the Origin of Language Postscript: On Path-dependence in Academic Cultural Evolution •!Path-dependence: the “you can’t get there from here” principle. •!Concept of multiple adaptive peaks in evolutionary theory. •!Concept of local stable equilibria in complex systems theory. •!Concept of paradigms in philosophy and history of science. • Needs to be taken seriously for major subject areas such as economics and linguistics Economics and Evolution as Different Paradigms •!Neoclassical economics is incapable of converging on realistic conception of human nature from an evolutionary, psychological, or even common-sense perspective. •!You just can’t get there from here. •!Necessary to go back to basics using a different set of initial conditions. • See my Evolution for Everyone blog for details. Linguistics and Evolution as Different Paradigms •!Linguists have always tried to consult evolutionary theory to the best of their ability in the construction of their paradigms. •!Early attempts severely limited by lack of knowledge. •!Even relatively modern attempts do not reflect the “cooperation came first” hypothesis. •!Path-dependence might prevent other paradigms from smoothly converging upon the paradigm that emerges easily from the “cooperation came first” hypothesis. •!We should be mindful of the “you can’t get there from here” principle in the future of linguistic inquiry.