Beyond exaptation:
The modules and metaphors program
Laurence Fiddick
James Cook University
The adaptivist program vs.
the adaptationist program
Adaptivist program – focused on the
reproductive consequences of traits. Traits
that increase reproductive success are
adaptive and held to be adaptations – the
product of natural selection.
The adaptivist program vs.
the adaptationist program
Adaptationist program – focused on
mechanisms that are complex and
functionally integrated – bear evidence of
special-design – which are held to be
adaptations.
Different programs, different problems
Adaptivist program – need to be vigilant for
traits that currently increase reproductive
success but lack the right evolutionary
history.
Adaptationist program – need to be vigilant
for traits that display evidence of special
design, but lack the right evolutionary
history.
Exaptations: An adaptivist’s problem
We suggest that such characters, evolved
for other usages (or for no function at all),
and later “coopted” for their current role,
be called exaptations (Gould & Vrba,
1982, p. 6).
Two sources of exaptation
A character, previously shaped by natural
selection for a particular function (an
adaptation), is coopted for a new use –
cooptation.
A character whose origin cannot be ascribed
to the direct action of natural selection (a
nonaptation), is coopted for a current use
– cooptation.
What Gould & Vrba do NOT say
They do NOT claim that randomly ordered
traits cannot be exaptations.
What Gould & Vrba DO say
They DO claim that all exaptations have
current utility.
A completely random, disorganized trait can
be an exaptation provided that it increases
current reproductive success.
Exaptations: the adaptivist’s headache
But what causes
the adaptationist to lose sleep?
Exadaptations: the adaptationist’s headache
Adaptations that have been largely been
coopted for new applications, regardless
of whether these new applications
increase reproductive success.
Other sources of complexly
organized functionality
Cultural evolution?
Intensive learning?
Human artifice?
Exadaptation: How does that work?
Adaptations – have an organized structure
embodying a particular mode of operation
(a modus operandi) that was designed for
a specific set of problems in ancestral
environments (a domain of application)
Exadaptation: How does that work?
Evolution through natural selection is a slow
process. Accumulated design is slow to
change.
Environments can change much faster
Exadaptation: How does that work?
The modus operandi of an adaptation is a
reflection of its accumulated design.
An adaptation’s domain of application is in
part determined by the environment in
which it operates.
Proper vs. actual domains
Exadaptation: How does that work?
With environmental change, the modus
operandi of an adaptation can potentially
organize a different domain of inputs.
Exadaptations: Do they exist?
Possible examples:
Moral disgust (Rozin, Haidt, & McCauley, 1999)
Written language (Pinker, 1994)
Law (Fiddick, 2004)
Mathematics (Dehaene, 1997)
Music (Dissanayake, 2000)
Poetry (Miall & Dissanayke, 2003)
Race (Gil-White, 2001; Hirschfeld, 1996; Kurzban, Tooby,
& Cosmides, 2001)
Religion (Boyer, 1994; Kirkpatrick, 1999)
Science (Atran, 1990)
Are these exaptations?
but
Possibly ….
... but
No effort to establish that these traits
increase current reproductive success.
Every effort made to understand the
organization of the phenomenon.
The organization of the phenomenon is
traced back in part to prior adaptations.
What would be a good example
of an exaptation?
Sperm bank donations – fairly high
probability that one’s reproductive success
will be increased by doing so but clearly
an evolutionarily novel behavior.
Increase Reproductive Success?
Yes
No
Music
Mathematics
Poetry
Science
Kinship Classification
Manipulation
Recycling Plastic
Sperm Bank Donations
Exaptations
Watching TV
Yes
No
Yes
No
Music
Mathematics
Poetry
Science
Kinship Classification
Manipulation
Recycling Plastic
Sperm Bank Donations
Exaptations
Watching TV
Exadaptations
Complex Functionality?
Increase Reproductive Success?
A systematic program of research
without a name
Moral disgust (Rozin, Haidt, & McCauley, 1999)
Written language (Pinker, 1994)
Law (Fiddick, 2004)
Mathematics (Dehaene, 1997)
Music (Dissanayake, 2000)
Poetry (Miall & Dissanayke, 2003)
Race (Gil-White, 2001; Hirschfeld, 1996; Kurzban, Tooby,
& Cosmides, 2001)
Religion (Boyer, 1994; Kirkpatrick, 1999)
Science (Atran, 1990)
The modules and metaphors program
Modules
An evolved faculty of mind that is flexibly,
domain-specific.
The proper domain of the mechanism is
given by its selective history.
Flexibility is brought about by changes in the
mechanism’s environment which affect its
actual domain of application, but not its
modus operandi
Metaphors
Taking a system of concepts and inferences
from a base domain and applying them to
a novel target domain.
Evolutionary theory as a scientifically
coherent account of base domains.
Evolutionarily novel situations as possible
target domains.
How does the program work?
1) Focus on a complexly organized, but
evolutionarily novel trait.
2
some practitioners even explicitly note that
this is what they are doing – e.g. Gil-White
and Kurzban et al. when investigating race
How does the program work?
1) Focus on a complexly organized, but
evolutionarily novel trait.
2) Characterize the modus operandi of the trait –
how is the phenomenon organized?
3) Draw parallels with a plausible adaptation that
possesses the same modus operandi.
4) Demonstrate a previously unknown aspect of
the novel trait that is known to exist in the
evolved trait or vice versa.
How does the program work?
1) Focus on a complexly organized, but
evolutionarily novel trait.
2) Characterize the modus operandi of the trait –
how is the phenomenon organized?
3) Draw parallels with a plausible adaptation that
possesses the same modus operandi.
4) Demonstrate a previously unknown aspect of
the novel trait that is known to exist in the
evolved trait or vice versa.
How does the program work?
1) Focus on a complexly organized, but
evolutionarily novel trait.
2) Characterize the modus operandi of the trait –
how is the phenomenon organized?
3) Draw parallels with a plausible adaptation that
possesses the same modus operandi.
Ideally…
4) Demonstrate a previously unknown aspect of
the novel trait that is known to exist in the
evolved trait or vice versa.
Is it compatible with
evolutionary psychology?
Critics of evolutionary psychology have argued
that precisely these sorts of phenomena are
incompatible with and raise serious doubts
about evolutionary psychology (Mithen, 1996;
Chiappe, 2000).
Violates evolutionary psychology’s presumed
modularity.
Is it compatible with
evolutionary psychology?
Evolutionary psychologists are committed to
the study of functional structure.
They assume that functional structure is
best explained in evolutionary terms.
Is it compatible with
evolutionary psychology?
Evolutionary psychologists are NOT committed to
the view that present environments are the same
as ancestral environments.
Given that the domain of an adaptation’s
application is in part a function of the
environment in which it operates, evolutionary
psychologists are NOT committed to the view
that the actual domain of a module is fixed.
Is it compatible with
evolutionary psychology?
Evolutionary psychology is compatible with
the possibility that novel environments can
alter the actual domain of an adaptation.
Evolutionary psychology is not compatible
with the possibility that novel environments
can alter the functional organization of an
adaptation – in function preserving ways.
The concept of metaphor, itself,
presupposes the preservation of conceptual
and inferential organization
from the base domain to the target domain.
What do evolutionary psychologists
have to gain from the program?
1) An alternative account of expertise
2) A defendable boundaries to adaptationist
proposals
3) A rich source of data
Face Processing
A
B
A
B
A
B
A
B
Kanwisher, McDermott, & Chun (1997)
Greebles
Gauthier, et al. (1999)
Gauthier, et al. (1999)
But…
Abacus experts show a bilateral increase in
superior frontal sulcus and superior
parietal lobule activation in a digit memory
task (Tanaka, et al. 2002)
Expert pilots show more frontal and
prefrontal activation, less visual and motor
activation in an aviation track-following
task (Peres, et al. 2000)
What do evolutionary psychologists
have to gain from the program?
1) An alternative account of expertise
2) A defendable boundaries to adaptationist
proposals
3) A rich source of data
Social Contract Theory (Cosmides, 1985)
Proposal: humans possess an evolved, “look for
cheaters” algorithm
Based on evolutionary theories of reciprocal
altruism (Axelrod, 1984; Axelrod & Hamilton,
1981; Trivers, 1971)
Evidence: studies conducted on the Wason
selection task
Social Contracts
If you take the benefit, then you must pay the cost
Two types:
Personal exchanges – two parties cooperating for
mutual benefit
Social laws – one person granted a benefit on the
basis of a societal law
If you take the benefit, then you must pay the cost
Only personal exchanges correspond to the form
of interaction modelled by evolutionary theory
Personal exchanges – two parties cooperating for
mutual benefit
Social laws – one person granted a benefit on the
basis of a societal law
Two possibilities
1) Amend the evolutionary theory
2) Draw a distinction between the proper
domain of the adaptation (personal
exchanges) and the actual domain of the
adaptation (personal exchanges and
social laws).
Social laws as a metaphorical extension
of cognitive adaptations for social
exchange
Do NOT claim that novel expressions of the
adaptation are part of its evolved function
What do evolutionary psychologists
have to gain from the program?
1) An alternative account of expertise
2) A defendable boundaries to adaptationist
proposals
3) A rich source of data
Psychological Experiments
Many psychological experiments used to
test adaptationist hypotheses rely upon
the application of mental adaptations to
evolutionarily novel situations.
Romance and Pornography
Given conflicts of interest between the two sexes,
it could be difficult to see the organization of
female and male mating psychology in their
unconstrained form.
The idealized worlds of romance literature and
pornography potentially represent a valuable
source of data about the ways that females and
males think about mating and sexual relations.
Fin
Social Contracts vs. Precautions
Reasoning about social contracts and
precautions is neurologically dissociable.
e.g., Stone, Cosmides, Tooby, Kroll, &
Knight (2002)
Precautions activate pain centers: insula and cingulate cortex
Fiddick, Spampinato, & Grafman (in prep)
Social contracts activate VLPFC and DMPFC regions
Fiddick, Spampinato, & Grafman (in prep)
But suppose one were to speculate that…
Catholicism is based on a “precautionary” logic.
The community is the body of Christ. Sin
constitutes a threat to one’s soul and the body of
Christ. Need to take precautionary measures to
protect one’s soul and heal any wounds it may suffer.
Protestantism is based on a contractual logic.
The community and one’s relation to God are
based on contractual relations placing one in a socially
precarious position (“you can be replaced”). Need to
establish “deep engagement” with God and members
of the community so that one is irreplaceable.
What about saints?
Catholics venerate saints, Protestants don’t
Specific saints for specific problems
Dysentery? Polycarp
Infertility? Agatha
Kidney disease? Ursus of Ravenna
Perhaps the psychology of hazards is
particularistic, whereas the psychology of
contracts is not:
Any item of trade can be exchange for any
other.