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Evolution and Political Decision Making


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Evolutionary approaches to political science are part of a behavioral revolution that is helping to shed new light on old problems and inspire novel hypotheses on emerging puzzles (Hafner-Burton et al. 2017; Kertzer and Tingley 2018). Prior misconceptions of evolutionary theory and its application to the social sciences have been usefully corrected or placed in their proper context, such as claims that natural selection produces inflexibly selfish individuals or that evolutionary processes are indeterminate models of political preference (Lopez, McDermott, and Petersen 2011; Lopez 2014, 2016b). An evolutionary model of political decision-making examines the link between a biological system and political outcomes, and explains the function of that biological system with reference to natural selection operating in ancestral environments (Lopez and McDermott 2012; Petersen 2015). Although our knowledge of ancestral environments is often incomplete, it is not fundamentally unknowable, necessitating methodological triangulation with complementary lines of evidence from many fields such as, but not limited to paleoanthropology, paleoarchaeology, geology, neuroscience, evolutionary game theory, primatology and behavioral ecology. Contributions of evolutionists to our understanding of political decision-making has yielded tangible benefits to a range of research questions, such as: When and why do we cooperate (Milner 1992; Axelrod 2006)? What is the origin and nature of political preferences and ideology (Alford and Hibbing 2004; Alford, Funk, and Hibbing 2008; Fowler and Schreiber 2008; Hatemi et al. 2009; Petersen 2012)? Why might someone sacrifice their lives for their group (Choi and Bowles 2007; Whitehouse 2018)? Why are leaders simultaneously sources of inspiration and insecurity (Smith et al. 2007; Rose McDermott and Hatemi 2014; Rose McDermott, Lopez, and Hatemi 2016; Lopez 2019)? Evolutionary approaches do not make context-general predictions about the content of preferences or beliefs; rather, we expect that organisms are “adaptation executors,” exquisitely sensitive to context in ways that would have been ancestrally adaptive, even if it appears irrational or maladaptive in modern contexts. Sometimes the behavior we observe will be entirely consistent with rational expectations, while at other times it will not be. Put differently, evolutionary approaches can sometimes be used to buttress existing claims, while at others it offers an empirically and ecologically valid replacement (Camerer 1998; McDermott, Fowler, and Smirnov 2008). Despite many gains, evolutionary approaches remain somewhat hindered by the same fundamental limitation that faces the behavioral sciences generally – the so-called “aggregation problem” (Powell 2017). However, this problem is tractable and no longer rests on fallacies that once asserted the blunt irrelevance of individual psychology. Instead, behavioral scientists progressively build a growing edifice of the many direct and indirect pathways by which individual psychology shapes political outcomes. The gains to be had are great, and the limitations are known and scalable.
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Evolution and Political Decision Making
Anthony C. Lopez, Washington State University
Summary: Evolutionary models of political decision making examine the link between a
biological system and political outcomes, and explain the function of that biological system with
reference to natural selection in ancestral environments.
(2019). Oxford Encyclopedia of Politics and Decision Making. Oxford University Press.
Evolutionary approaches to political science are part of a behavioral revolution that is helping to
shed new light on old problems and inspire novel hypotheses on emerging puzzles (Hafner-
Burton et al. 2017; Kertzer and Tingley 2018). Prior misconceptions of evolutionary theory and
its application to the social sciences have been usefully corrected or placed in their proper
context, such as claims that natural selection produces inflexibly selfish individuals or that
evolutionary processes are indeterminate models of political preference (Lopez, McDermott, and
Petersen 2011; Lopez 2014, 2016b).
An evolutionary model of political decision-making examines the link between a
biological system and political outcomes, and explains the function of that biological system
with reference to natural selection operating in ancestral environments (Lopez and McDermott
2012; Petersen 2015). Although our knowledge of ancestral environments is often incomplete
, it
is not fundamentally unknowable, necessitating methodological triangulation with
complementary lines of evidence from many fields such as, but not limited to paleoanthropology,
paleoarchaeology, geology, neuroscience, evolutionary game theory, primatology and behavioral
Contributions of evolutionists to our understanding of political decision-making has
yielded tangible benefits to a range of research questions, such as: When and why do we
cooperate (Milner 1992; Axelrod 2006)? What is the origin and nature of political preferences
and ideology (Alford and Hibbing 2004; Alford, Funk, and Hibbing 2008; Fowler and Schreiber
2008; Hatemi et al. 2009; Petersen 2012)? Why might someone sacrifice their lives for their
group (Choi and Bowles 2007; Whitehouse 2018)? Why are leaders simultaneously sources of
inspiration and insecurity (Smith et al. 2007; Rose McDermott and Hatemi 2014; Rose
McDermott, Lopez, and Hatemi 2016; Lopez 2019)? Evolutionary approaches do not make
context-general predictions about the content of preferences or beliefs; rather, we expect that
organisms are “adaptation executors,” exquisitely sensitive to context in ways that would have
been ancestrally adaptive, even if it appears irrational or maladaptive in modern contexts.
Sometimes the behavior we observe will be entirely consistent with rational expectations, while
at other times it will not be. Put differently, evolutionary approaches can sometimes be used to
buttress existing claims, while at others it offers an empirically and ecologically valid
replacement (Camerer 1998; McDermott, Fowler, and Smirnov 2008).
Despite these many gains, evolutionary approaches remain somewhat hindered by the
same fundamental limitation that faces the behavioral sciences generally – the so-called
“aggregation problem(Powell 2017). However, this problem is tractable and no longer rests on
fallacies that once asserted the blunt irrelevance of individual psychology. Instead, behavioral
scientists slowly build a growing edifice of the many direct and indirect pathways by which
individual psychology shapes political outcomes. The gains to be had are great, and the
limitations are known and scalable. Before reviewing some of these gains and limitations, a few
words of orientation are in order regarding what is meant by an evolutionary approach to
political decision making.
The Difference Between Biological and Evolutionary Models of Behavior
There is a temptation to conflate an “evolutionary” approach with a “biological” approach, but a
more useful taxonomy would view the former as a subcategory of the latter. Biological
approaches include any attempt to explain political behavior with reference to biological systems
regardless of whether the design or function of those systems is explained as a product of
evolutionary dynamics, such as natural selection. As one example of a biological approach to
politics that is not evolutionary, researchers increasingly make use of physiological measures
such as skin conductance reactivity to measure physiological arousal to political stimuli
(Renshon, Lee, and Tingley 2015). In this case, Renshon and colleagues directly examine the
link between a biological system and political outcomes, but the authors make no mention or use
of evolutionary theory to explain either the existence or design of the underlying biological
system itself. Although an explanation of the design and operation of a biological system must
invoke evolutionary processes, scholars sometimes find it sufficient to merely describe the
operation of the biological system and to associate its operation with a political behavior of
interest without invoking evolution to explain why the system exists, or why the system operates
the way that it does. This is not a demerit; rather, it is a convenience.
However, when one’s hypotheses invoke evolutionary processes to explain the existence
or design of biological systems that are purported to be relevant for political behavior, then the
approach is evolutionary. Thus, the mere referencing of some aspect of human biology is not
sufficient to render an approach “evolutionary”; evolutionary approaches are biological, but the
reverse is not necessarily true. The focus of this article will be on research that links biological
systems with political outcomes, and explains either the existence or design of those systems
with respect to evolutionary dynamics such, as natural selection.
It should also be recognized that in practice, evolutionary analysis has been applied to
political phenomena in two very distinct ways: one applies evolution in a biological sense; the
other applies evolution in a metaphorical sense. The former is the focus of this article, while the
latter takes the general principles and themes of evolution and applies them to social phenomena,
often over great historical periods, but without specific claims regarding biologically evolved
systems. Such an approach, for example, might examine the “evolution” of military strategy over
the centuries, invoking concepts from evolutionary theory such as principles of “selection” and
“co-evolutionary” dynamics (Levy and Thompson 2011). This approach can be quite useful and
productive, yet is similarly outside the scope of this article. An evolutionary approach to politics,
which can be distinguished from mere descriptions of biological systems or the use of
evolutionary metaphors, requires an interrogation of biological design.
Adaptationism and the Study of Biological Design
The use of evolution to explain political decision making requires a deep and careful
examination of first principles of evolutionary biology. There is no way around it. Scholars who
attempt to apply findings from the evolutionary sciences without a careful understanding of these
first principles will often end up propagating fallacies that could and should be avoided (Lopez
2016b). Problematically, however, the effort to deeply and constructively engage the
evolutionary sciences can easily lose the attention of political scientists or indeed specialists of
any social science, since it requires a complicated and time-consuming foray into the jargon,
theory, and evidence of foreign research lands. This is not an insurmountable hurdle; it simply
reminds us that some cross-disciplinary forays may be more time consuming than others. For
example, a political scientist will likely find it easier to absorb theory and evidence from
economics than from evolutionary theory. This simply means that greater care must be made to
clarify the theoretical commitments and scope of evolutionary approaches relative to other
disciplines that may be “closer to home” for political scientists.
Given the boundary conditions outlined above, there are two broad evolutionary
approaches to politics: Adaptationism and heritability. The two approaches differ in a variety of
complex ways, but the simplest distinction may ultimately be the most important: the former
takes as its unit of analysis complex adaptations that are often – but not always – species typical
(i.e. human ‘universals’), while the latter takes as its unit of analysis any aspect of individual
differences that is explained by genetic differences between individuals. I focus on
adaptationism, while acknowledging that heritability approaches are diverse, productive and
expanding (Eaves et al. 2008; P K Hatemi et al. 2008; Joseph 2009; Ebstein et al. 2010; Smith et
al. 2011b; Lopez and McDermott 2012; Plomin et al. 2016).
What is adaptationism? Adaptationists attempt to explain complex biological design as
products or by-products of natural selection operating over long evolutionary periods. Put
simply, natural selection builds adaptations, and adaptationists seek to explain the existence and
design of the latter in terms of the former.
To begin, therefore, we first recognize that the
phenotype (or physical structure) of all organisms is under the constant push and pull of natural
selection and entropy. Fundamentally, the former organizes, while the latter disorganizes. In a
general sense, therefore, “evolution,” as a process of change, describes the unfolding of that push
and pull over extremely vast time periods. While adaptationists focus on the products of natural
selection (i.e. adaptations), we cannot ignore the fact that the phenotype does not consist solely
of adaptations (Mayr 2001), which is in part where heritability approaches are most useful
(Lopez and McDermott 2012; Tooby and Cosmides 1990).
How does natural selection “build” adaptations? From generation to generation, as a by-
product of the reproductive process, genetic mutations arise that have a positive, negative or
neutral effect on an organism’s reproductive success (Daly and Wilson 1983; Mark Ridley
2004). Natural selection describes an inter-generational “sift” (or algorithm, following the
philosopher Daniel Dennett), whereby mutations (i.e. genes, or alleles) that have a positive effect
on reproductive success become more common in a population relative to other variants of that
mutation (Maynard Smith 1998). Importantly, new genetic variants are never inherently
beneficial; rather, their reproductive benefit is measured relative to the effects of alternative
variants, and these reproductive benefits are often specific to a certain environment and would
fail to be similarly beneficial in different environments (Williams 1966; Symons 1992). For
example, overwhelming arousal at the scent of dung is highly adaptive for the dung beetle, yet
for humans, such a response would be embarrassing at best and reproductively counterproductive
at worst. There is nothing about the environment that is intrinsically triggering, and there is no
genetic variant or phenotypic trait that is intrinsically beneficial; rather, it is the unique fit
between the two that explains the design and variety of adaptations within and across species.
Apropos, dung triggers arousal in the dung beetle but activates disgust mechanisms in humans.
In both instances, the same cue triggers distinct behavior regulating mechanisms.
The only way to understand how and why a given context triggers an evolved behavioral
or motivational repertoire is by investigating the selection pressures that would have been unique
to that organism in its ancestral environment. Organisms are adapted to a prevailing past, not
modern novelty. As a useful clarification, therefore, evolutionary psychologists say that each
adaptation has its own corresponding “environment of evolutionary adaptedness” (EEA), or
ancestral environment in which it was reproductively beneficial (Tooby and Cosmides 1992).
Thus, to understand the design and function of an adaptation we must examine its EEA, which
often requires a careful methodological triangulation of both known and inferred elements of
ancestral environments. A full exploration of the evidentiary criteria and methodological tools
employed by evolutionists is outside the scope of this article; however, many useful surveys exist
(Tooby and DeVore 1987; Cosmides and Tooby 1987; Confer et al. 2010; Lopez and McDermott
2012; Petersen 2015; Mark Ridley 1985; Mayr 1983).
Each organism confronts a unique range of threats and opportunities in its environment
that have an effect on reproductive fitness and can be referred to as “adaptive problems.” To
describe the sifting process of natural selection in terms of these adaptive problems, therefore,
we would say that natural selection has the effect of maintaining phenotypic traits, arising via
genetic mutation, that have the on-average effect of helping to solve these adaptive problems.
The accumulation and integration of these traits over evolutionary time can result in complex
adaptations (Dawkins 1986; Maynard Smith 1993). Thus, each adaptation or set of adaptations is
a genetically-encoded phenotypic solution to ancestrally recurrent and reproductively significant
challenges, which are specific to the environment in which the organism evolved. Even in cases
of “convergent evolution,in which geographically distant species evolve similar adapatations
(e.g. eyes), the specific form and function of these visual systems reflects the resolution of
adaptive problems that are specific to the environments in which the organism evolved (Carroll
Adaptations are built-in responses to ancestrally prevalent reproductive challenges.
However, given the long time periods over which natural selection works, many organisms,
including humans, may confront modern situations of “evolutionary mismatch.Since much of
the evolutionary analysis of political decision-making hinges on this idea of mismatch, it is
worth spending some time on its meanings and implications (Rosen 2007; Johnson, Wrangham,
and Rosen 2002; McDermott, Fowler, and Smirnov 2008).
Evolutionary mismatch
First, recall that adaptations are solutions to selection pressures that are reproductively
significant and ancestrally recurrent. In a sense, many psychological adaptations can be
understood as physically instantiated “best bets,” and for this reason they are sometimes also
referred to as evolved heuristics or “privileged hypotheses” of the mind (Petersen 2015). In short,
evolution has built a range of psychological adaptations that are designed to expect certain
combinatorial regularities in the environment and to respond with a host of relatively automatic
inferences, motivations or behaviors that would have been adaptive in ancestral environments.
Some aspects of the adaptively relevant environment change quickly, others change
gradually, and still others do not change at all. The coelacanth is a marvel of evolution since it is
one of the longest living species in the world (evolutionarily speaking) yet has exhibited
relatively little change over this extensive period, largely due to the fact that its environment is
uncommonly static (Matt Ridley 1994). Humans, however, occupy a niche that has changed in
many ways, both quantitative and qualitative. A discussion of the full typology of historical and
evolutionary change and its effects on psychology is outside the scope of this discussion;
however, it is also unnecessary in order to establish a simpler taxonomy of pathways whereby
environmental change has unexpected effects on evolved systems. In general, we can identify at
least 2 ways in which a mismatch can occur between the environment the adaptation “expects”
and the environment it actually engages.
First, it may be the case that we possess adaptations that are designed to confront a
reproductively significant challenge that is simply no longer present in any form. In this case, we
might expect the adaptation to essentially lie dormant and be under the disorganizing pull of
entropy, given that its fitness consequences may no longer be positive (Carroll 2006).
the adaptive problem persists, but in altered form, and its form may be altered quantitatively,
qualitatively, or both. In the case of our “small-scale” psychology confronting the world of
modern mass politics, what we are often really talking about is a partial evolutionary mismatch.
A well-known example of partial mismatch is the case of the human “sweet tooth.” Since
foods high in sugar content would have been rare and costly to pass up in ancestral
environments, it is said that we have an evolved bias toward consuming all that we can when we
come across foods that are sweet to the taste. This behavioral repertoire (“if you find sweet stuff,
eat as much as you can!”) was an evolutionary “best bet” in environments where sugary foods
were rare. In modern environments, sugary foods are relatively abundant. Even without knowing
the specific reproductive consequences in modern contexts of consuming sugary foods to your
heart’s desire, we can say two things: it is a case of partial mismatch, and it often has negative
health consequences in the modern world. It is a case of partial mismatch because we possess
evolved systems designed to expect that a particular feature of the environment will exist but be
rare; now, however, it continues to exist but is more common than in ancestral environments.
Yet, because evolution operates slowly over thousands of generations, the bias continues to
operate, motivating levels of consumption that can lead to negative health consequences. It could
be that these negative health consequences also lead to negative reproductive consequences, but
this is an empirical question and it is largely beside the point if our goal is to explain and predict
behavior. In other words, we can use evolutionary analysis to identify cases of mismatch, we can
use analysis to explain and predict what behavior might look like in altered environments, and
we can even design public policy interventions based on this knowledge. The key point is that all
of this is possible without any consideration of whether the inferences, emotions and behaviors
generated in modern, evolutionarily novel environments is maladaptive or even “irrational.”
Such considerations (i.e. “Is it maladaptive?” “Is it irrational?”) are simply not useful.
matters is knowledge of the design of the adaptation given the environment in which it evolved,
and our ability to use that knowledge to help explain and predict behavior in novel environments.
Another example of partial mismatch comes from research on coalitional competition in
humans and other primates, which has demonstrated that one cue of central importance in
determining the likelihood and outcome of coalitional aggression and violence is relative
numbers. In chimpanzees, for example, an imbalance of power between groups is often
singularly sufficient to trigger coalitional aggression between them (Wrangham 1999). Although
it is not so decisive in human groups (Wrangham and Glowacki 2012), a predisposition to
emphasize numerical strength persists in modern international politics, even at the expense of
attributes that are at least as relevant, if not more so, to modern battlefield victory . If, as
mentioned previously, adaptations are “evolutionary best bets,” then a coalitional psychology
that is designed to help us navigate the world of coalitional conflict is basically generating a set
of inferences, motivations and behavior that would have correlated with victory in ancestral
environments, even if that is at odds with the modern determinants of victory.
Modern environments may be different from ancestral environments in both quantitative
and qualitative ways, and although distinction can be murky, this is less important than the
general recognition that some environmental changes occur on a clear single dimension – e.g.,
the size of groups – while others are more complex. Greater nuance is not necessary to
investigate here beyond simply pointing out that such considerations are too often overlooked,
and that scholars investigating mismatch hypotheses could give greater care to the type of
mismatch and its effect on behavior, rather than simply asserting that a changed environment has
resulted in irrational or maladaptive behavior (Li, van Vugt, and Colarelli 2018).
Evolutionary mismatch is an unavoidably central element to most evolutionary analyses
of political decision making for two reasons. First, politics is ancient. For as long as we have
lived in groups, we have faced challenges of a “political” nature regarding, for example, resource
distribution, authority, security and collective action. Second, modern politics is a clear shadow
of its ancestral forms. In some ways, modern politics is wholly unique, but in many ways, it
mirrors – however imperfectly – the same sets of challenges we have faced in groups for
millennia. The distribution of wealth, concerns about inequality, beliefs about who “deserves”
the group’s help, intuitions about foreigners, reactions to external threat and the problem of
deterrence are all challenges that human groups have faced over the course of our long
evolutionary history and have certainly had reproductive consequences (Lopez and McDermott
2012; Petersen 2015; Peter K. Hatemi and McDermott 2011). These challenges are inherent to
what many political scientists recognize as the core questions of their discipline, as reflected in
Harold Lasswell’s (1936) classic definition of politics as the question of “who gets what, when
and how.” In international relations as well, Robert Gilpin (1984) acknowledges that humans are
a “tribal species,” in which coalitional politics is central to interpretation and motivation even
among nation states under anarchy. If modern politics triggers adaptations designed for the
small-scale environments of our ancestors, we gain an important analytic tool for understanding
the origin of political preferences as well as the specific aspects of the modern environment that
trigger those evolved systems, even – perhaps especially – when those environments have
changed dramatically.
Domain specificity
As previously mentioned, adaptationists seek to explain the existence and design of
psychological mechanisms with reference to ancestral selection pressures. Given that evolved
systems exhibit a function that reflects the structure of a specific adaptive problem (The beaks of
Darwin’s finches being the classic example), we also say that adaptations are “domain-specific,
meaning they are designed to operate in specific ways in specific environments. From this
perspective, the mind contains a host of specialized adaptations, each designed to solve adaptive
problems that prevailed over evolutionary time in unique ancestral environments. This
perspective is sometimes referred to as “modularity,” and without unpacking related debates on
just how “massively” modular the mind is, it is sufficient to recognize that the most crucial
element in this view of the mind is that it has been shaped by natural selection, and that the
resultant “programs of the mind” are specialized systems designed to solve adaptive problems.
Many potential implications of this perspective seem reasonable but are in fact not valid, and it is
worth identifying them.
First, this view does not imply or argue that the brain consists solely of psychological
adaptations. This is false, even on an a priori basis, given that the products of evolution are not
only adaptations, but also by-products of adaptations as well as genetic and phenotypic “noise”
or individual differences that are not to be explained as products of natural selection (Tooby and
Cosmides 1990; Lopez and McDermott 2012; Mayr 1983; Godfrey-Smith and Wilkins 2008).
Furthermore, the question of whether the brain is “mostly” composed of adaptations is similarly
unimportant, since the more relevant question is: what adaptations exist and how do they
Second, the adaptationist view of the brain makes no specific claims about the physical
structure of the brain. Most adaptationists remain agnostic on the so-called “hardware” of the
brain, while focusing instead on the design of its “software.” In other words, we find it sufficient
to investigate how the brain is designed to process information in ways that would have been
ancestrally adaptive without (typically) asking the related but distinct question of how that
system is physically instantiated. Nevertheless, it is useful and increasingly possible to expose
the links between the “hardware” of the brain and its information-processing “software(Mineka
and Öhman 2002; Ermer et al. 2006; Takahashi et al. 2006)
Third, there is debate about whether all evolved mechanisms are domain-specific, or
whether domain-general mechanisms also exist; i.e. systems whose basic logic operates across a
very broad range of contexts or domains rather than being specific to a relatively narrower subset
of related contexts. For the purposes of this article, it is sufficient to note that the function of a
complex adaptation largely reflects the informational structure of an adaptive problem, so it is, in
principle, impossible to say, a priori and generally, “how specialized” adaptations must be, and
whether they must all be specialized to a similar degree. The link between adaptation and
selection pressure matters more than the resultant degree of specificity itself.
Humans are adaptation executors
Psychological adaptations are the necessary link between evolution and behavior. These evolved
systems function to produce outcomes that would have yielded - on-average - reproductive
benefits in ancestral environments. This means that humans are not consciously trying to
maximize fitness, even if the mechanisms that shape motivation and behavior are designed to
achieve such outcomes. A taste for sex and sugar, independent of any awareness or concern for
their ultimate function and adaptive value, are just two of the more dramatic examples of this.
Thus, if one finds it necessary to describe human decision-making in general terms, the most
accurate description is that humans are “adaptation executors” (Tooby and Cosmides 1992)
rather than utility maximizers or fitness maximizers.
The level of selection debate
There is disagreement on the “level” at which natural selection builds adaptations. For example,
does natural selection operate at the level of individual organisms, or at the level of groups of
organisms? The individual level of selection is relatively intuitive and can be said to operate
when genes spread in a population because they generate benefits for the individuals that possess
them. This level approximates common and popular understandings of how natural selection
works. Group selection, however, is often invoked to explain the existence of adaptations that
seem to motivate behavior (e.g. heroic self-sacrifice) that appears disadvantageous for the
individual (e.g. risk of personal harm) yet highly beneficial for the individual’s group (e.g.
greater odds of victory in warfare). In other words, in group selection, the differential survival
and reproduction of groups rather than the differential survival and reproduction of individuals is
the means by which a gene spreads in a population.
In the extreme, for example, groups that were exterminated in battle in part due to low
cohesion or coalitional investment, were not likely to pass on their genes to future generations.
Over time, via the success of groups that contained individuals with the heritable tendency to be
prosocial, genes for prosociality spread at the expense of alternative miserly variants.
Importantly, the basic underlying mechanism of natural selection is always the same regardless
of the level of selection: genes spread in frequency that have the effect of producing more copies
of themselves. In other words, there is no disagreement that genes constitute the fundamental
unit of selection, yet there is disagreement regarding the level at which selection operates.
The level of selection debate asks a specific question: what is the mechanism by which
genes become more frequent in a population – via the success of individuals or via the success of
groups? The answer, like so much else, is that it depends. For some adaptations, group selection
may offer the most feasible explanation, while for other adaptations, individual selection may be
more accurate. In practice, the debate contains two nodes of contention: First, is group selection
theoretically feasible as an evolutionary force? Second, does group selection yield predictions
that are distinct from individual level selection?
Generally, the level of selection debate has moved on from questions of whether group
selection was an important force in human evolution to the more specific questions of what
adaptations has it shaped and how (Sober and Wilson 1999; Nowak, Tarnita, and Wilson 2010;
Okasha 2010; Nowak 2012; Lopez 2014; Richerson et al. 2016; Eldakar and Wilson 2011),
although many continue to contend that some of its predictions do not diverge from those of
individual level selection (Delton et al. 2011; Price 2012; Gneezy and Fessler 2011).
Furthermore, debate is now more open to the possibility that in some instances, adaptations are
best explained by selection having operated at more than one level simultaneously. This is
sensibly referred to as “multi-level selection.” Adaptationism contains no a priori commitment
to natural selection operating at any level, although an argument from parsimony is sometimes
made, which claims that the level of selection that is invoked should be the lowest necessary to
sufficiently explain the range of observed variation (Williams 1966; Price 2012).
Evolution and Politics
The foregoing discussion has been a detailed yet condensed overview of an interdisciplinary
approach laden with arguments and concepts that are unfamiliar to most political scientists. This
effort is necessary given not only the ‘disciplinary distance’ from our home field of study, but
also the ease with which it is possible to misunderstand how evolution works and what it
produces. Having now outlined the contours of an adaptationist approach to behavior and some
of its implications, we are prepared to focus attention on how such an approach can illuminate
analyses of political behavior.
The nature of political decision making
The study of political behavior by political scientists and other social scientists, has spawned
myriad theories, paradigms, and schools of thought, each with their own familiar labels, such as
realism, liberalism, or rationalism. Furthermore, these labels can mean different things to
students of different subfields, for example, depending on whether one is trained as an
international relations scholar or a student of voting behavior. Nevertheless, research paradigms
often come with a commitment to one or a combination of three features. The first is the content
of preferences – what do actors want? The second is the mechanics of decision making, which
refers to the (often internal) process by which preferences are turned into choices. Third, there is
some statement about the theoretically relevant environment, or those aspects of the environment
that “matter more” than others in terms of their behavior-shaping effects.
In international relations, for example, realism and liberalism each make distinct
arguments about the content and ranking of preferences, and they have competing arguments
about what aspects of the world matter more for explaining political outcomes. Yet they are both
relatively agnostic on decision-making mechanics – i.e. how political actors actually make
decisions. In contrast with realism and liberalism, rational choice theorists focus more on how
political actors make decisions, by identifying maxims or axioms by which preferences are
structured and decisions are made, such as transitivity and dominance (McDermott 2004). Unlike
realism and liberalism, rationalism makes no commitment to any feature of the world mattering
more for states; rather, it offers a means by which to explain outcomes given a range of
environmental constraints of interest to the researcher. Although rationalists are relatively
agnostic about the content of preferences (as well as the nature of the environment), they often
do assume that actors are self-interested. However, this assumption, like many (all?) assumptions
of rationalism, is easily replaced with contrasting assumptions, which in this case would be
“other-regarding” or “prosocial” interests (Powell 2017).
In contrast to these paradigms, evolutionary models of behavior make no general
arguments or assumptions regarding the content of preferences, the mechanics of decision
making, or the theoretically relevant environment (See Table 1). The answer to all three
questions is always: it depends. And what it depends on is context. In a way, therefore, the core
theoretical ambition of evolutionary approaches to political behavior is unpacking the many
ways in which certain contexts facilitate differential patterns of reasoning and behavior. It is a
truism that context matters, but the value of an evolutionary approach is that it provides a
rigorous theoretical framework for thinking about which contexts matter, when they matter, why
they matter, and how. Evolutionary approaches offer no a priori theoretical claims about what
people want the most (egoism v. altruism, power v. wealth), how people always make decisions,
or which features of the environment are most important (e.g. anarchy, for realists in
international relations). As is now clear from the discussion above, natural selection builds
adaptations in organisms that are designed to solve specific kinds of problems that were unique
to their ancestral environment. By extension, modern contexts that mirror those ancestral
challenges should continue to actively shape behavior today.
Evolutionary models of behavior provide a lens that can be useful for either correcting or
complementing the insights of existing theories or paradigms. For example, evolutionary models
can shed light on the motivations that fuel pernicious international competition (Thayer 2004;
Johnson and Thayer 2016), they can help to explain the allure of institutions such as democracy
(Boyer and Petersen 2011; Lopez 2016b), and they allow us to impute more ecologically valid
preferences into game theoretic decision-making models (Gigerenzer 2000; Maynard Smith
1982). In contrast to Goodwin and others, for example, evolutionary approaches unequivocally
do not presuppose selfish actors (Goodwin 2010; Lopez 2014). Indeed, evolutionary approaches
have been so valuable precisely because of their ability to explain both cooperative and
competitive dynamics (Axelrod 1984; Gat 2000; Alford and Hibbing 2004a). This is not
evidence of indeterminism in evolutionary approaches (Bell 2006); rather, it is evidence of its
broad utility (Lopez, McDermott, and Petersen 2011).
Lastly, evolutionary approaches face challenges of scaling from the individual to the
group, yet this is not any truer of evolutionary approaches than it is of research in the behavioral
sciences generally (Powell 2017). Although there is growing consensus that macro phenomena
must rest on sound micro foundations (Hafner-Burton et al. 2017), the pathways by which the
latter shapes the former remain somewhat opaque. Importantly, no alternative theoretical
paradigm fares much better. Furthermore, it is largely, but not exclusively because of these
limits, that alternative models of political decision making – such as rationality and
constructivism – remain prominent.
Table 1. Anatomy of a Decision
Unit of Analysis
Domestic & int’l
Non-state actors
Content of
Seek relative
Seek absolute
Function of
relevant context
Mechanics of
Decision Making
Distribution of
Environment of
Evolutionary Politics: Gains and limitations
The synthesis between evolution and politics has yielded tremendous gains, yet one of the most
striking features of research on the evolution of political behavior is that most of it is not being
done by political scientists. Instead, the charge is being led principally by psychologists,
anthropologists and economists. In part, this is due to the fact that, at least for psychology and
anthropology, these disciplines are somewhat “closer” to the language and frameworks of
evolutionary science. Nevertheless, a growing cadre of political scientists apply theory and
evidence from evolutionary models of behavior to political questions, particularly, but not
exclusively, at the level of individual behavior and domestic politics (Petersen 2019; Smith et al.
2011a; Peter K. Hatemi and McDermott 2011; Petersen 2012). In this review, however, I focus
in particular on research on leadership and political conflict, and rather than offer a full review of
these areas, I engage key and illustrative findings in depth.
Two general elements unite most evolutionary models of political behavior. First, there is
a recognition that some aspect of politics is shaped, however indirectly, by a biological system.
This system can range from physiological arousal, endocrine pathways such as testosterone or
oxytocin, as well as information-processing systems in the brain that regulate inferences,
motivation and behavior. Second, the existence and design of that biological system is explained,
at least in part, in terms of ancestral selection pressures. For example, the psychologist John
Archer has proposed the “challenge hypothesis” that explains the fluctuations of testosterone as
part of an behavior-regulatory system that evolved because it regulates dominance and
submission in adaptively useful ways (Archer 2006). Applying these understandings of the
endocrine system, researchers hypothesized that testosterone is similarly active in regulating the
responses of members of political parties to victory and defeat in modern elections (Stanton et al.
2009). In short, scholars first recognize that a biological system shapes political phenomena, and
scholars use evolutionary theory to generate hypotheses about the way in which that biological
system operates and effects, or is effected by, political phenomena.
Leadership is a dynamic that is of central importance across the social sciences. Even outside of
the social sciences, researchers who study animal behavior care a great deal about relationships
of asymmetric influence, sometimes merely understood as dominance, due to their significant
effects on the distribution of material and reproductive resources, and which can have important
relationships for group and alliance structures (Harcourt and Waal 1992). Although the extreme
institutional centralization that is characteristic of modern political leadership is undoubtedly an
evolutionary novelty, what is not new is the prevalence of asymmetries of social influence and
the striving for influence that is perhaps as old as groups themselves (Eldakar et al. 2018). Even
in hunter-gatherer societies that are characterized by the relative absence of clear or codified
leadership roles, there are often strong rules and norms against the striving for power and
influence that is indicative of a constant understanding and wariness of the social consequences
of concentrated power (Boehm 1999). In other words, humans seem to instinctively understand
what it means to strive for influence and to yield to the influence of another, and there is growing
evidence that humans possess an automatic and universal appreciation of the significance of
attributes associated with leadership, such as prestige and dominance (Boehm 1999; Henrich and
Gil-White 2001; Smith et al. 2007; Boehm 2012; Price and Van Vugt 2014; von Rueden et al.
2014; von Rueden, Gavrilets, and Glowacki 2015; Garfield, von Rueden, and Hagen 2019).
Although we spend a great deal of time in our lives purposely thinking about and talking
about leaders, it is important to remember that here, as well as in many other domains of social
interaction, much of our reasoning and motivation is implicit and unconscious. For example, and
generally, humans automatically and effortlessly pay great attention to facial features when
evaluating who to trust, who not to trust, the desirability of a mate, and even the potential
efficacy of political leaders. This is likely in part a consequence of psychological adaptations
designed to detect reliable cues in facial structure that have ancestrally correlated with
personality traits and behavior. For example, Haselhuhn and Wong (2011) show that genetically
conditioned physical attributes such as facial width-to-height ratio reliably predict a tendency to
deceive and cheat others, as well as propensity for aggression. Other studies have shown that
subjects are surprisingly good at distinguishing cheaters from cooperators based merely on
having viewed pictures of people’s faces (Yamagishi et al. 2003). And, children are surprisingly
good at predicting the outcome of elections based on candidate pictures alone (Antonakis and
Dalgas 2009). In other words, stable environmental cue structures (e.g. facial width-to-height
ratio) have reliably correlated with fitness-relevant behavior in others (e.g. deception), such that
natural selection has favored adaptations for detecting such cues and for regulating behavior
contingent upon their detection.
Why should it be the case that facial features have been evolutionarily reliable indicators
of personality traits? Sexually dimorphic facial features develop around puberty and are triggered
by underlying changes in hormones such as testosterone. Testosterone itself is strongly related to
aggression, sensitivity to threat, relatively selfish behavior in many economic games, and it has
also been found that increases in testosterone tend to correlate negatively with empathy toward
others (Booth et al. 1989; Kouri, Lukas, and Pope 1995; Van Honk et al. 1999; Archer 2006;
Burnham 2007; Zak et al. 2009; Van Honk et al. 2011).
Given the fact that particular facial cues
have been evolutionarily reliable indicators of certain personality traits, it is no surprise that
psychological adaptations should be designed to attend to these cues when regulating motivation
during inter-personal, as well as coalitional, interactions. The fitness benefits of attending to
such adaptively relevant cues are obvious, not only in the realm of cooperation and mating, but
also in contexts of political leadership. Thus Spisak et al. (2012) find that people rely on visual
cues in the face when choosing a political leader, and that people tend to prefer masculine faces
in wartime and feminine faces in peacetime. These findings are both provocative and highly
illustrative of an evolutionary approach to political phenomena, so it is worth further elaborating
the adaptive mechanism.
Spisak and colleagues argue that the challenge of finding, establishing, and maintaining
leadership for collective action was a reproductively significant adaptive problem for our
ancestors. Indeed, both the reproductive and material benefits of effective leadership for groups
in certain contexts – especially collective action – appear substantial (Betzig 1986; van Vugt and
Kurzban 2007; Smith et al. 2007; Hooper, Kaplan, and Boone 2010; van Vugt and Ahuja 2011;
McDermott and Hatemi 2014; Glowacki and von Rueden 2015; McDermott, Lopez, and Hatemi
2016). Indeed, this constitutes the lion’s share of research on leadership from an evolutionary
perspective. However, not all collective action is the same, which suggests that “different
leadership prototypes” may be more effective in different situations, given that those distinct
situations were evolutionarily recurrent. The authors therefore argue that, “A key adaptive
challenge then is for group members to identify an individual to follow in any particular
situation.” Spisak et al. argue that this is essentially a process in which leaders are chosen who
most closely match the leadership prototype that is best suited for the specific context of
collective action. The two leadership prototypes that the authors consider are represented by
facial masculinity and facial femininity, while the adaptively-relevant contexts of collective
action that they consider are warfare and peacetime. The choice of collective action context
seems intuitive (i.e. war vs. peace), but why have Spisak and colleagues chosen facial
masculinity and femininity as leadership prototypes? The answer again has to do with the
underlying personality traits with which these facial cues reliably correlate. As the authors put it,
the “differentiated constellations of skills required for competition or cooperation seem to
parallel phenotypic associations with hormones such as testosterone and estrogen.” In other
words, testosterone reliably correlates with facial masculinity and dominance, while estrogen
reliably correlates with facial femininity and cooperativeness, and of course there may be certain
contexts in which a dominant leader may be more effective, and certain contexts in which a
cooperative leader may be more effective.
These findings help to underline the central and unique importance of context in
evolutionary analysis. Spisak et al. hypothesize that in the context of warfare, masculine faces
will be preferred over feminine faces as a consequence of the fact that facial masculinity reliably
correlates with the personality traits that are likely to have been most useful during ancestral
inter-group conflict. In contrast, in the context of peacetime, feminine faces should be preferred
over masculine ones for opposite reasons. The authors show that it is not the sex of the
candidate that matters; instead, “masculine-females are preferred as leaders over feminine-males
for war and the converse for peace.” Spisak and colleagues also show that the effect holds cross-
culturally, by comparing effects in Western and East Asian population samples. Furthermore,
political scientists have shown that the effect holds also for the pitch of a candidate’s voice
(Anderson and Klofstad 2012; Klofstad, Anderson, and Petersen 2012). However, Lausten and
Petersen (2017) convincingly show that preferences for leader dominance are determined
exclusively by wartime and not peacetime contexts. In other words, as the authors explain,
“humans by default prefer nondominant and nonexploitative leaders but…contextual needs for
collective action enforced by a leader can lead followers to change these preferences” (1097).
Furthermore, Lausten and Petersen show that individual level dispositions for dominance (e.g.
social dominance orientation) correlate with a preference for dominant leadership generally.
These studies suggest that humans possess psychological adaptations that are designed to
actively track cues in the environment such as facial masculinity/femininity, which ancestrally
correlated with fitness-relevant behavior and personality traits. Importantly, these systems
operate largely outside of conscious awareness. In our interactions with others, we do not
consciously and deliberately scan for variables such as the degree of genetic relatedness and
facial width-to-height ratio and then use such variables to compute an optimal level of
cooperation; instead, natural selection designs systems that operate below consciousness and
produce output that we experience as attraction, trust, or avoidance. As these findings suggest,
these systems operate at all levels of social interaction, from the interpersonal to the political.
Behavioral scientists, as well as political scientists, continue to add nuance and rigor to our
understanding of how humans instinctively engage questions of political leadership across many
levels of analysis (Laustsen and Petersen 2018; Grabo and van Vugt 2018).
Inter-group conflict
Scientific study of the evolution of inter-group conflict and warfare has matured greatly.
Historically, debates have been unduly distracted with questions such as whether humans are
naturally selfish or altruistic. Partly stemming from misapplication of metaphors such as
“survival of the fittest” and the “struggle for survival,” it was often assumed that Darwinian
processes could only produce selfish individuals that care not for the welfare of others (Goodwin
2010). In the case of coalitional violence, early ethologists argued that chimpanzees and humans
naturally strive to dominate each other and that aggression is the inevitable consequence of
competitive social environments. The lesson was: we are stuck with violence, aggression, and
war, so we must learn to deal with it. Proponents of what is sometimes called the “killer ape”
hypothesis viewed instinct and innateness as a source of inflexibility and inevitability (Horgan
Modern evolutionists recognize that although adaptations for aggression are innate, they
are hardly inflexible (Wrangham 1999; Sell, Tooby, and Cosmides 2009); indeed, psychological
adaptations that regulate social behavior must prove flexible if they are designed in response to
the complex selection challenges that prevailed in ancestral social environments. In other words,
adaptations for warfare must render coalitional aggression a conditional response to adaptively
relevant environmental circumstances. For example, McDonald et al. (2012) build an
evolutionary framework for understanding the psychology of intergroup conflict. McDonald and
colleagues begin with sexual selection and parental investment theory (Trivers 1972; Symons
1979; Buss and Shackelford 1997; Buss 2003) to explain that ancestrally, engaging in coalitional
aggression was a relatively low-cost, high-benefit reproductive strategy for males more so than
for females. Briefly, in any species where a stable parental investment asymmetry exists between
two sexes, the low investors tend to compete over access to the high investors, and natural
selection tends to favor various “weapons” (e.g. aggressiveness) for use in these intra-sexual
contests. In humans, as with most primates and mammals in general, males are the low investors
and the more aggressive sex. In the context of coalitional aggression, this investment asymmetry
renders warfare a reproductively beneficial activity even in the face of substantial mortality
(Tooby and Cosmides 1988; Lopez 2016a).
Given an ancestral social environment characterized by inter-group conflict in which
coalitional aggression was reproductively beneficial for males more than females, McDonald and
her colleagues outline two sets of hypotheses regarding the adaptations that ought to exist for
warfare and how they are expected to operate. The first is the Male Warrior Hypothesis. If
coalitional aggression was primarily a male endeavor, it is likely that adaptations for warfare
operate in distinct ways depending on the sex of the individual. Adaptations in males should
render coalitional aggression conditional upon cues such as personal and coalitional
formidability; in-group members should be more suspicious of out-group males than out-group
females, and; out-group males should tend to provoke anger and aggression among in-group
males, but should provoke fear and avoidance among in-group females. Indeed, the authors find
that, compared to women, men are in general more xenophobic, and are more likely to
dehumanize out-group members. Additionally, when primed with out-group threat, male - but
not female - in-group identification, as well as willingness to sacrifice for the group, becomes
amplified. McDonald et al. explain that a range of adaptations ought to exist to defend against
the threat of out-group male coalitions - a set of expectations that they refer to as the Outgroup
Male Target Hypothesis. Here as well, political scientists continue to test, extend and find
support for a range of hypotheses consistent with this evolutionary framework of war (Thayer
and Hudson 2010; Lopez 2017; Lindner 2018).
Scholarship on the evolution of warfare often confronts compelling and sometimes
puzzling comparisons with non-human primates, such as chimpanzees. For example, many
evolutionists will point to the existence of chimpanzee coalitional aggression as evidence that the
origin of warfare extends back even before the hominid-chimpanzee split (Wrangham and
Peterson 1996). However, it is noteworthy that the predominant form of chimp coalitional
violence is the lethal raid, initiated in the backdrop of inter-group competition, and typically
when a favorable size ratio (3:1) permits low-risk victory by the larger coalition. Humans, on the
other hand, not only demonstrate a greater degree of inter-group trade, alliance and cooperation
than chimpanzees, but also demonstrate a relatively greater willingness to engage in coalitional
violence even when the balance of power between coalitions is relatively symmetrical. In other
words, we are both more willing to build and maintain cooperative alliances, and more willing to
engage in high-risk inter-group violence. Although the chimpanzee model predicts that humans
(like chimpanzees) evolved adaptations to conditionally engage in low-risk, high-probability of
success coalitional aggression, the fact that humans engage in riskier forms of relatively
symmetrical coalitional aggression, seems to suggest that alternative hypotheses to the
chimpanzee model must also be explored.
One possible explanation is that greater risk-taking on the battlefield is better explained
as the product of cultural norms that compel risky behavior rather than biologically instantiated
decision-rules (Wrangham and Glowacki 2012). Alternatively (perhaps additionally), the
analysis by McDonald et al. (2012) suggests that even in the face of significant mortality, it is
still possible for individual level selection to favor great risk-taking in battle. If we take seriously
the significant reproductive benefits to be had from coalitional violence for males, then the
puzzle may not be why humans engage in risky symmetric coalitional aggression, but rather,
why chimpanzees and other primates do not. Part of the solution may indeed lie in cultural
innovations and institutions that compel coalitional participation. However, another part of the
answer likely rests in the unique nature of human coalitional psychology, which facilitates n-
person coalitional activities that are both quantitatively and qualitatively distinct from those of
chimpanzees, and enables culturally complex solutions to problems other primates may not be
able to solve absent this psychology (Tooby, Cosmides, and Price 2006; Lopez 2016a).
Nevertheless, this remains an open and compelling avenue for investigation. Research on
biological and cultural mechanisms that sustain participation in warfare have focused on a range
of formal and informal punishments (Price, Cosmides, and Tooby 2002; Mathew and Boyd
2011; Lopez 2017) and incentives (Glowacki and Wrangham 2013). However, research has also
demonstrated that the mere awareness of inter-group conflict or out-group threat itself is often
sufficient to provoke participation, punish free riding and reward contribution (Puurtinen and
Mappes 2009; Gneezy and Fessler 2011).
Much of the research on the evolution of war has focused on how it emerged historically
as well as evolutionary comparisons with non-human primates. Recent work, as discussed above,
has focused more squarely on the underlying coalitional psychology (Sheremeta 2017).
However, in terms of modern warfare, perhaps the most interesting trend is that inter-state
violence is on the decline and is instead eclipsed by insurgent violence and civil war. A
particularly prominent feature of the modern landscape of political violence is the phenomenon
of radical extremism, and it is here as well that evolutionists have turned their attention.
Although there is no consensus on a definition of extremism (or even related terms such as
terrorism), several lines of evolutionary research help to unpack the psychological underpinnings
of dynamics intimately related to what one might recognize as extremist violence: the evolution
of religion (Boyer 2002; Ginges, Hansen, and Norenzayan 2009; Atran and Ginges 2012; Haidt
2013); the psychology of sacred values (Tetlock et al. 2000; Tetlock 2003; Ginges and Atran
2011; Atran and Ginges 2012; Atran 2016); and the psychology of parochial altruism or simply,
“heroism” (Choi and Bowles 2007; Orbell and Morikawa 2011; Rusch, Leunissen, and van Vugt
2015). The anthropologist Harvey Whitehouse (2018) proposes a model of “identity fusion” that
integrates various lines of research to explain when and why individuals of a group are
predisposed toward costly sacrifices on behalf of their group. Supported by cross-cultural and
field evidence (Whitehouse et al. 2014), these arguments help to explain, in the words of one
recent paper, “how moments become movements” (Buhrmester et al. 2018).
Limitations: The aggregation problem
Research on evolution and war provides a useful segue into a discussion of what is sometimes
referred to by international relations scholars as the “aggregation problem,” which is the puzzle
of explaining “how individual preferences and actions aggregate up into a group outcome”
(Powell 2017, 266). This problem, however, has come a long way from a prior consensus in
international relations that the so-called individual level of analysis was of “questionable
relevance,” either because human nature, as a “constant” could not explain the variable outcomes
of international relations, or simply because such an investigation would inevitably lead one to
the study of “moods which cannot be grounded in fact” (Waltz 1959; Kelman 1965; Blainey
1988). Nevertheless, a “behavioral revolution” is sweeping through political science, and even if
the aggregation problem still lacks a direct and clear resolution, political psychologists continue
to chip away at this now-tractable puzzle (Hafner-Burton et al. 2017; Kertzer and Tingley 2018).
However, it is worth taking a step back and considering what exactly the aggregation problem is,
and how much of a hurdle it actually poses, in order to place evolutionary approaches to
decision-making in their proper context.
The aggregation problem has historically taken at least one of two forms: An ontological
objection and a methodological objection. Ontologically, critics such as Waltz have argued that
extrapolating from the individual level to the international level is untenable, due to properties of
individual psychology or human nature itself (e.g. human nature, or psychology, as a constant
cannot explain a variable). Second, there is a methodological objection. Methodologically, critics
invoke some form of emergent property claim; namely, they argue that the social whole is
greater than, and cannot be reduced to, the sum of its individual parts. In short, the ontological
claim is that “going from” the individual to the group is not possible; the methodological claim is
that it is simply not appropriate or useful.
Others, such as Byman and Pollack (2001), have attempted to categorize and respond to
similar objections. They identify three. First, again from Waltz, that human nature is a constant
and cannot explain variable international phenomena; Second, that first image (i.e. individually-
based) approaches are not parsimonious; Third, that first image approaches lack relevance
because they are essentially “drowned out” by superordinate pressures at the international level –
such as the security dilemma – that force behavioral convergence despite individual-level
variance in preferences. The first objection Byman and Pollack identify is substantively similar
to what I label the ontological critique. Regarding the second, there is little disagreement over
the loss in parsimony, and in any event, the more important question is whether the purchase of
accuracy outweighs the loss in parsimony. The third objection identified by Byman and Pollack
is ultimately an empirical question regarding the “contextualism” of personality as a variable
(e.g. under what conditions do leaders matter?), which cannot be answered a priori.
The fallacy of viewing human nature as a constant has been adequately discussed
elsewhere (Lopez, McDermott, and Petersen 2011). Research in many fields from psychology
and anthropology to evolutionary biology and behavioral economics has revealed that human
psychology is a complex web of neurochemical processes, built by natural selection, shaped by
daily experience, and subject to deep and meaningful variation despite a species-typical substrate
(Gazzaniga, Ivry, and Mangun 2009). The ontological objection is simply meritless. More useful
is the methodological objection.
The methodological objection arises most powerfully in response to the use of market
analogies for explaining the link between individual preferences and group outcomes. Market
analogies tend to be methodologically individualist (Schelling 1978; Pettit 1996) and explain
group behavior as the aggregate and additive product of individual-level local interactions. This
approach is common to classical models of microeconomics, in which it is the aggregate supply
and demand that together determine price at the macro level. Thus, explaining macro phenomena
entails merely identifying the preference structure of individuals and the decision-making
procedures that they utilize when making local economic choices to maximize welfare. In other
words, if the actors are all constituted by the same simple decision-making procedures, then
explanations of group behavior become increasingly tractable to the extent that we have a good
understanding the local conditions that actors face.
A common objection to market-based analogies and approaches, both beneath and above
the state, is that groups are more than the mere aggregation of the individuals that compose them.
In other words, when individuals interact in a given social space, the result of these interactions
is a range of “social facts” and phenomena that somewhat autonomously constrain the
individuals whose interactions helped to produce them. These “emergent properties” are the
often-unintended aggregate by-products of local interactions. Emergent properties are a real and
important component not only of social life, but also of most forms of biological organization
(Camazine et al. 2003).
This emergent property problem is a more specific version of the aggregation problem
and can take various forms, such as the agent-structure problem or the debate between
methodological individualism and holism (Wendt 1987, 1992). When it is levied against
individual-level psychological explanations for behavior, however, the emergent property
critique does not claim that group behavior cannot be explained with reference to the individuals
that compose them. Rather, it rejects the possibility that the causal relationship between
individual attributes and social outcomes is additive in nature. Given that individual-level
psychological arguments about political groups are neither mono-causal nor additive, emergent
property claims are more useful for reminding us of the existence of important social facts (e.g.
norms and institutions) and less useful as arguments against the validity of psychological
approaches to macro phenomena.
Indeed, the pathways that connect micro dynamics and macro phenomena are myriad,
encompassing what I will call both direct and indirect pathways (Table 2). Direct pathways
typically come in top-down and bottom-up variants. Direct top-down pathways are those that
examine how psychological attributes located at the “top” of the group have a conforming or
unifying effect upon its behavior. This approach, for example, might examine a leader or a “k-
group” that has disproportionate control over a state’s behavior. Direct bottom-up pathways are
those that examine how psychological attributes located at lower levels of the state hierarchy
organize foreign policy or constrain it directly and “from below.” This approach might examine
the constraining attributes of public opinion or social identity on foreign policy. In contrast to
both forms of direct pathways, indirect pathways explain state behavior and systemic aggregates
as the product of interactions between psychological attributes and specific aspects of socio-
institutional environments.
Table 2. How do you get from the individual to the group?
This analysis provides an useful opportunity to observe an important mismatch between modern
and ancestral politics. Ancestrally, given the much smaller scale of group living, political
questions were quite literally in your face, providing frequent avenues of direct bottom-up
pressures and constraints. This would not be to deny the existence of the other pathways; rather,
it is to emphasize the relative strength of direct bottom-up influences in ancestral environments.
Modern politics necessarily encompasses a complex range formal and informal institutions and
legal structures, meaning that it is likely that direct bottom-up pathways are the less visible,
supplanted in prominence by direct top-down pressure, especially by leaders, and indirect
pathways of interaction between our evolved psychology and institutional constraints and
incentives (Cosmides and Tooby 2006; Boyer and Petersen 2011).
Taken together, the conclusion is that evolutionary approaches, along with other
individual-level approaches of the behavioral sciences, trade some parsimony in exchange for
internal and ecological validity. The relevant goal is to expand our knowledge of the direct and
indirect pathways by which individual-level attributes shape macro-phenomena. Depending on
the goals of their research, scholars will sometimes find this useful, and at other times, they will
prefer to continue to treat individuals as rational or groups as unitary actors. This remains a
matter of methodological convenience and usefulness.
The application of evolutionary theories or models to explain political decision making is
relatively young, fundamentally interdisciplinary, and irreducibly complex. This hybridization
has yielded significant benefits, including real progress toward understanding the conditions
under which cooperation is possible, and a clearer understanding of the apparently “irrational”
drivers of political violence. Evolutionary models of political decision making continue to
mature greatly, placing us in a position to usefully take stock of the research landscape. Doing so
crystalizes the promises, perils and scope of evolutionary approaches to politics.
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Indeed, as scholars who study war will immediately understand, even our knowledge of modern
environments is woefully incomplete.
I will sometimes use the active voice or anthropomorphisms when describing the operation or
effects of natural selection. This is always a shorthand convenience and never meant to imply
conscious effort or foresight in the mechanics of natural selection. In this particular case, natural
selection is obviously not “building” adaptations the way a human might build a house. Rather,
natural selection occurs via a passive sifting processes whereby genes experience directional
change in frequency in response to environmental pressures across generations. To say that
natural selection “builds” adaptations is meant exclusively as a shortcut to bypass lengthy verbal
repetitions of this process.
Caveats include but are probably not limited to cases of exaptation.
Note that the question “is it maladaptive?” is really only half of the full question “is it maladaptive today?” Yet,
given that natural selection is a sifting process that maintains traits that have the on-average effect of enhancing
reproductive fitness relative to alternative traits, the claim that a trait is maladaptive today is only meaningful if we
can know something about future environments and the existence of heritable alternative traits in that future.
Neither information is typically available, and thus the issue of current maladaptation is little more than a topic of
interesting speculation. Not only is it possible to analyze mismatch without interrogating maladaptation, one
should actively avoid the latter in favor of the former.
Importantly, testosterone is part of the human endocrine system and operates in interesting and
complex ways with other hormones, which is an area of active study (Liening and Josephs 2010;
Mehta and Josephs 2010).
Debate continues on whether this phenomenon is better explained by individual or group
selection. See for example (Jordan, Jordan, and Rand 2017)
ResearchGate has not been able to resolve any citations for this publication.
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The present research replicates and extends previous literature on the evolutionary contingency hypothesis of leadership emergence. Using artificially masculinized versus feminized versions of the faces of the candidates for the 2016 U.S. presidential elections, we demonstrated that different contextual cues produced systematic variation in both preferences for and personality impressions of leadership. We describe results of an online study (N = 298), demonstrating that followers who perceived a match between the contextual prime (intergroup conflict or cooperation) and a leader candidate’s relevant physical cues (masculinized or feminized versions of their faces) both (a) preferred them as leaders and (b) rated them more positively on personality attributes commonly associated with effective leadership such as trustworthiness, warmth, competence, and charisma.
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Can moments of viral media activity transform into enduring activist movements? The killing of Cecil the lion by a trophy hunter in Zimbabwe in 2015 attracted global attention and generated enduring conservation activism in the form of monetary donations to the research unit that was studying him (WildCRU). Utilizing a longitudinal survey design, we found that intensely dysphoric reactions to Cecil's death triggered especially strong social cohesion (i.e., “identity fusion”) amongst donors. Over a 6-month period, identity fusion to WildCRU increased amongst donors. In addition, in line with an emerging psychological model of the experiential antecedents of identity fusion, cohesion amongst donors increased most for those who continued to reflect deeply on Cecil's death and felt his death to be a central event in their own lives. Our results highlight the profound capabilities of humans to commit resources to supporting others who are distant in space and time, unrelated culturally or biologically, and even (as in this case) belonging to another species altogether. In addition, our findings add to recent interdisciplinary work uncovering the precise social mechanisms by which intense group cohesion develops.
Whether upheld as heroic or reviled as terrorism, throughout history people have been willing to lay down their lives for the sake of their groups. Why? Previous theories of extreme self-sacrifice have highlighted a range of seemingly disparate factors such as collective identity, outgroup hostility, and kin psychology. This paper attempts to integrate many of these factors into a single overarching theory based on several decades of collaborative research with a range of special populations, from tribes in Papua New Guinea to Libyan insurgents, and from Muslim fundamentalists in Indonesia to Brazilian football hooligans. These studies suggest that extreme self-sacrifice is motivated by ‘identity fusion’, a visceral sense of oneness with the group resulting from intense collective experiences (e.g. painful rituals or the horrors of frontline combat) or from perceptions of shared biology. In ancient foraging societies, fusion would have enabled warlike bands to stand united despite strong temptations to scatter and flee. The fusion mechanism has often been exploited in cultural rituals, not only by tribal societies but also in specialized cells embedded in armies, cults, and terrorist organizations. With the rise of social complexity and the spread of states and empires, fusion has also been extended to much larger groups, including doctrinal religions, ethnicities, and ideological movements. Explaining extreme self-sacrifice is not only a scientific priority but also a practical challenge as we seek a collective response to suicide terrorism and other extreme expressions of outgroup hostility that continue to bedevil humanity today.
Political psychology in international relations (IR) has undergone a dramatic transformation in the past two decades, mirroring the broader changes occurring in IR itself. This review examines the current state of the field.Webegin by offering a data-driven snapshot analyzing four years of manuscript classifications at a major IR journal to characterize the questions that IR scholars engaged in psychological research are and are not investigating. We then emphasize six developments in particular, both present-day growth areas (an increased interest in emotions and hot cognition, the rise of more psychologically informed work on public opinion, a nascent research tradition we call the first image reversed, and the rise of neurobiological and evolutionary approaches) and calls for additional scholarship (better integration of the study of mass and elite political behavior and more psychological work in international political economy). Together, these developments constitute some of the directions in which we see the next generation of scholarship heading. Expected final online publication date for the Annual Review of Political Science Volume 21 is May 11, 2018. Please see for revised estimates.