Over the last three decades, popular science authors have used evolutionary mismatch theory to shed light on a vast number of modern social problems, pointing to differences between contemporary environments and those of humanity’s distant ancestors. These authors argue that the majority of Homo sapiens’ existence took place in the Pleistocene (approximately 2 million to 10,000 years BCE), and so this epoch presented the greatest adaptive challenges to the species’ survival and reproduction. These were the contexts that shaped modern human physiology and sociality through natural selection. Large-scale civilizations, they argue, no longer resemble this so-called “environment of evolutionary adaptedness,” even though the humans that inhabit them retain the genetic and psychological makeup of their Pleistocene precursors. Many contemporary problems of Western social life, the story goes, can thus be attributed to this mismatch between the evolved human-animal and the novel problems of the present. As evolutionary psychologists John Tooby and Leda Cosmides are frequently quoted, “our modern skulls house a stone age mind” (Shenkman 2017: xv).
Theories of evolutionary mismatch have spread to a surprising variety of popular media, addressing many topics, including: disease and disability, diet, addiction, crime, environmental destruction, romantic jealousy, and commercial consumption. These arguments are striking because they attempt to point out modern crises, constructing the moral urgency of evolutionary science as it could (ostensibly) apply to contemporary problems. They describe circumstances in which human physiological adaptations do not meet the stresses of their environments: immune systems lack sufficient defenses; metabolisms do not match food consumption; individuals misread social cues and so act in irrational, sometimes destructive ways. Mismatch theorists thus shift discussions of scientific knowledge from description to prescription. They position themselves as both popularizers of science and humanitarian activists. Yet, their theory rests upon an internal ambiguity that calls the usefulness of their perspective into question, as I examine here.
Mismatch of two sorts
In my research, I investigate the rhetorical situations constructed by authors of mismatch arguments, looking at the ways that authors frame particular exigencies, the constraints that shape their arguments, and the audiences to whom these arguments are made (Bitzer 1968). My findings demonstrate that two kinds of argument circulate about evolutionary mismatch: on one hand, theorists suggest that contemporary humans’ ancestral instincts are “leading them astray.” Peoples’ reactions to contemporary stresses might overestimate the danger of low-level stresses while dismissing more abstract threats, such as the long-term risks of smoking or environmental destruction. These authors thus argue that a mismatch exists between the psychologies inherited from our Pleistocene ancestors and the more complicated challenges to health and happiness in modern civilizations. Minds that are adapted to “flight or fight” are unprepared for today’s complexities.
Yet, other theorists make a contrary point: their audiences need to re-harness the lost wisdom of their ancestors, finding the means to health and happiness outside of the seductions of post-industrial civilization. In this sense, modern environments are dangerous and unhealthy to the human-animal whose habits and needs were “forged” several hundred thousand years ago. Today’s social problems can only be addressed by returning to our instinctual lifeways.
Together, these arguments compose a movement in popular evolutionary science with numerous branches: Paleo diet enthusiasts focus on obesity, hypertension, physical inactivity, and food addictions. Theorists in Darwinian medicine draw attention to chronic disease, hygiene, and antibiotics. Ancestral fitness advocates focus on exercise, strength training, and the alienation of cosmopolitan life from the natural world. So-called Darwinian psychiatry similarly attempts to treat the effects of depression and anxiety as mismatches between ancestral and contemporary life. Still other authors examine issues such as pornography addiction, poor body image, and even poor political leadership and voter apathy.
The rhetorical situations of mismatch
While drawing from the multiple fields that constitute evolutionary science (Darwinian theory, genetics, paleoanthropology, primatology, ethology, etc.), mismatch authors are commonly aiming toward pragmatic, proactive goals. In many cases, these goals might be described as ‘self-improvement’. These are expressly directed toward individual readers, making arguments for simple lifestyle changes that will (among other benefits) combat depression, increase physical or emotional energy, or improve one’s sense of self. The problems to which these authors draw attention lie in our immediate environments, and so those environments need to change.
In Supernormal Stimuli, for example, Deirdre Barrett offers an instance of evolutionary mismatch taking shape in issues of personal body image and advertising. She argues that Pleistocene ‘ideals’ of health and beauty are mismatched to today’s consumer culture:
“If a Stone Age girl wasn’t the prettiest in her small tribe, the difference wasn’t likely to be dramatic. Everyone had opportunities to see others looking their worst—tired, bedraggled, sick—as well as on their best days. Now society culls from millions of young women to select the best faces and bodies, and then perfects these with Adobe Photoshop” (2010: 36).
In Why We Get Sick, Randolf Nesse and George Williams similarly argue that the effects consumer culture can result in low self-image, making one’s own accomplishments seem insignificant. Mass communication and pop culture, they write,
“effectively make us all one competitive group even as they destroy our more intimate social networks. Competition is no longer within a group of fifty or a hundred relatives and close associates, but among five billion people […]. In the ancestral environment you would have had a good chance at being best at something. Even if you were not the best, your group would likely value your skills. Now we all compete with those who are the best in all the world” (1994: 220).
In such instances, authors often employ the rhetoric of entitlement, suggesting that readers recognize their “evolutionary birthright” (Boaz 2002: 4) or make lifestyle changes that “we all need to reclaim from our ancestors” (Ilardi 2009: 9). Evolutionary mismatch thus points to the health and happiness that has been “denied” modern humans by their present circumstances.
Yet, the goals of mismatch theorists may also lean toward a kind of scientifically-informed activism. We must, they argue, challenge unjust or unwise socio-economic or environmental policies as the dangerously limited thinking of the ‘old minds’ of the Pleistocene. Robert Orstein and Paul Ehrlich, for instance, argue that
“hundreds of thousands or millions of years ago, our ancestors’ survival depended in large part on the ability to respond quickly to threats that were immediate, personal, and palpable […]. Those are not threats generated by complex technological devices accumulated over decades by unknown people half a world away. Those are not threats like the slow atmospheric buildup of carbon dioxide from auto exhausts, power plants and deforestation” (1989: 8).
In such situations, mismatch theorists employ the rhetoric of dysfunction, positing that “in many ways our instincts are obsolete” (Shenkman 2017: xv) and arguing that social problems can only be solved by rejecting the Pleistocene impulses, because “that’s what our giant brains were designed for – overriding reflexive instincts when they start to lead us astray” (Barrett 2010: 176-177)
Mismatch theories all generally agree that an animal (Homo sapiens) that was primarily adapted to survival in ancient circumstances is now struggling in its present environments. The problems of modern life are largely of humanity’s own making, and so theorists introduce a rhetoric of Promethean tragedy: the human-animal is a creature that has intellectually and technologically outgrown its own, modest origins. Whether these ancestral origins are a birthright to be reclaimed or reflexive instincts to be overridden is often unclear. In either case, the mismatch between Pleistocene and contemporary, Western lifeways offers audiences the primary explanation that “we were not designed for the modern world” (Shenkman 2017: xiv).
The rhetorical functions of ambiguity
As is apparent in these examples, mismatch theory capitalizes on the ambiguity that surrounds much of the human evolutionary past. The fossil record does not offer ample support for theories of Pleistocene body-image or interpersonal competition. Yet, I would argue that the ambiguity of mismatch performs an important (if problematic) rhetorical function for its authors: it would seem that any modern problem could be explained as an evolutionary mismatch. Evidence for this clearly lies in the vast and varied numbers of social problems they have targeted. Authors explain these exigencies by pinning the blame on our “insufficient” instincts or (conversely) our “inattention” to ancestral ways of health and happiness. Put to this purpose, the term “mismatch” possesses endless flexibility. Its exact meaning cannot be pinned down, save for its seemingly unwavering rhetorical function: it speaks of a modern social problem (one of very, very many), critiques our contemporary responses, and repeatedly stresses the importance of juxtaposing these problems and responses to an imagined past.
In semiotic analyses, a concept such as mismatch is often called a “floating” signifier, describing rhetoric with such numerous and slippery meanings that it can feasibly construct any argument. The floating signifier can pragmatically extended, in order to draw urgent attention (and action) toward a wide number of possible exigencies. As explained by linguistic anthropologist Bonnie Urciuoli, a signifier like mismatch becomes “a lexical item or expression deployed in different discursive fields so that, in effect, people using term X in a referring expression in field A are engaged in a different pragmatic activity from those using the formally identical term X in a referring expression in field B” (2003: 396). Depression or anxiety, for example, may be considered to be adaptive “cries for help” (signaling a need to return to more ancestral social support systems) or as maladaptive reactions to modern stresses (calling for more appropriate responses to present day pressures). The loose constraints within such strategies thus allows not only for countless possible exigencies to be outlined, but also for a variety of sometimes-contradictory interpretations and solutions to be put forward.
The audience for mismatch arguments is just as ambiguous. A text might target a particular topic (obesity, depression, addiction, etc.), but the distinguishing qualities of any single audience are remarkably vague. Authors assume their audiences share their own dissatisfaction with that status quo, or the “usual” way of dealing with social problems. Their audience can also be assumed to agree that the recent findings of science might resolve these problems. More abstractly, they can assume that their readers agree that all modern humans are a single species, and so they are the products of evolution through natural selection. While this last assumption certainly excludes creationists and evolution deniers from its potentially receptive audience, authors are otherwise free to speak as if they are addressing the species as a whole. Indeed, one author goes so far as to dedicate his book: “To Homo sapiens, that they may learn to live with themselves.”
These ambiguities are, I suggest, symptomatic of much of human evolutionary theory, as it enters into public discourses. Evolutionary biology has been employed to support dozens of political ideologies (e.g. socialism, capitalism, anarchism), socio-economic policies (neo-liberal expansion, immigration restriction, eugenics), and spiritual persuasions (natural theology, pantheism, atheism). But within such disparate applications lie a profound, epistemic inexactness, which allows one to vigorously argue for any “side”: social welfare or self-interested conservatism, radical reform or a maintained status quo, and even the existence or absence of an omniscient deity. Such a strategy could conceivably ‘explain everything’ while ultimately showing its audiences very little. This is the case with mismatch.
2010 Supernormal Stimuli: How Primal Urges Overran Their Evolutionary Purpose. New York: W.W. Norton and Company.
Bitzer, Lloyd F.
1968 The Rhetorical Situation. Philosophy and Rhetoric 1: 1-14.\
Boaz, Noel T.
2002 Evolving Health: The Origins of Illness and How the Modern World Is Making Us Sick. New York: John Wiley and Sons.
Ilardi, Stephen S.
2009 The Depression Cure: The 6-Step Program to Beat Depression without Drugs. Boston: De Capo Press.
Nesse, Randolph M. and George C. Williams.
1994 Why We Get Sick: The New Science of Darwinian Medicine. New York: Vintage Books.
Ornstein, Robert E. and Paul R. Ehrlich
1989 New World New Mind: Moving Toward Conscious Evolution. New York: Doubleday.
2016 Political Animals: How Our Stone-Age Brain Gets in the Way of Smart Politics. New York: Basic Books.
2003 Excellence, Leadership, Skills, Diversity: Marketing Liberal Arts Education. Language and Communication 23: 385-408.