Download Multilevel Selection, Meaning Systems, and the Evolution of Language

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.