NEW RESEARCH PROJECT: “The Post-War Human: A Physiological History of the Species During the Great Acceleration, 1945-2001”

On a physiological and cognitive level, would a group of ten thousand thirty-year-old women and men born in 1955 be on average the same as a group of ten thousand thirty-year-olds born half a century earlier in the year 1905?

The goal of “The Post-War Human” research and book project is to examine the possibility that the answer to this question is “no”: that many of the humans who lived in 1985 were significantly different at a material organismal level than their ancestors who lived in 1935, and, if the evidence suggests this was indeed the case, to consider how these changes might have affected the history of the post-war era. Until very recently, most scholars have generally assumed that historical change occurs solely because events, ideas, and cultures changed, not because the human beings who interacted with these changes were themselves materially changing at an organismal level. With a few narrowly defined exceptions—changes in health or height, for example—the material nature of the human animal was assumed to be essentially fixed and thus irrelevant to explaining the course of history.[1]

Today, however, this assumption appears increasingly problematic as scientists and humanists alike come to better understand the many ways in which human bodies and minds are embedded in a material environment that surrounds, shapes, and permeates them. Consider, for example, that since 1945 the production of synthetic chemicals increased more than thirty-fold. Today there are roughly 80,000 synthetic chemical in wide use in the United States, of which only about 200 have been tested for their effects on humans. Many of these chemicals now saturate our environments and bodies through our daily interactions with plastics, pesticide residues, chemically treated clothing and furniture, and many other pathways. As the historian Julia Adeney Thomas recently observed, our chemical environment is not just around us or in us, “our chemical environment is us.” Indeed, given the rapidity and scale of these changes, Thomas poses the provocative question that is at the heart of this project: “Is it not possible that the Anthropocene’s sudden chemical acceleration now separates us physiologically from prewar human beings?”[2]

Yet this new chemical environment is only one of many other radical environmental modifications that constitute what the historian John McNeill and others have aptly termed the Great Acceleration.[3] McNeill and other humanists and scientists note that since 1945 humans in many regions around the planet have increasingly lived in strikingly different material environments than had predominated in previous eras. Perhaps the most widely recognized change has been the massive increase in the use of fossil fuels and its effects on global climate. Yet a very partial list of other material changes during the Great Acceleration would also note that:

·      global population doubled from 3 to 6 billion;

·      the number of automobiles rose from 40 to 700 million;

·      billions moved from rural farms and villages to cities so that today more than half the people on the planet are urban dwellers;

·      communication via telephones increased by a factor of four;

·      and international travel increased by a factor of six.[4]

To varying degrees, historians and other humanists and social scientists have recognized and studied all of these phenomena and others. However, most have focused on delineating their socioculturally mediated effects. Relatively few have asked how these vast material changes might have affected the physiological and cognitive substrate of human beings and with what consequences for the course of historical change.[5]

If (and this remains very much a research question the project seeks to answer) many post-war humans were (and still are) materially different than pre-war humans, to effectively analyze this era presents daunting methodological challenges. To manage these, LeCain proposes to begin by expanding on the theoretical and methodological concepts and tools developed in his 2017 book, The Matter of History: How Things Create the Past.[6] Here he draws on new scientific and humanistic insights such as the human microbiome[7], epigenetics[8], the Extended Evolutionary Synthesis[9], and the extended mind[10], as well as new ideas from anthropology, environmental history, archaeology, and critical theory, to develop a neo-materialist theory and methodology. In essence, LeCain argues that these radical new ideas of what it means to be human demand that historians develop a more materially grounded understanding of the past, one in which we view human creativity, ideas, and culture as emerging from their interactions with a dynamic environment that, at least in some cases, literally is them.

These methods offer a good starting point for considering the immense material environmental changes experienced by many post-WWII humans. But to make such a potentially vast project manageable, LeCain proposes to drastically narrow its scope in several ways. First, while it inevitably undermines any claim to being truly a species-level history, the project will focus on areas of the globe where the Great Acceleration has been most pronounced. While this will foster considerable attention to Euro-American nations and related colonial and post-colonial states, the project will, depending on the available evidence, also seek to include similarly modernized nations like Japan, India, South Korea, China, Egypt, and South Africa, among others. Second, the project will narrow its focus to several specific case studies, which could include:

·      Antibiotics, Processed Foods, and the Microbiome—Given the growing post-war use of broad-spectrum antibiotics with their now-widely-recognized effects on the human microbiome’s production of psychotropic substances like serotonin, might it be possible to include these physiological changes as a contributing factor in social, cultural, and political events?[11] A similar question might be raised regarding highly processed foods whose effects were certainly not only cultural, but also physiological.

·      Chemicals, Pollution, and Culture—As noted above, many post-war humans came to swim in a vast sea of synthetic chemicals as well as a range of other potentially mind- and body-altering pollutants. This is well known, yet has been approached almost entirely as a public health issue rather than in terms of historical change and causalities. More recently, scientists and social scientists have begun to interrogate how these chemicals affect sociocultural phenomena like civic participation and criminality. In part, these effects are a result of the adverse cognitive effects of exposure to these pollutants in utero or early-life. As the authors of a 2018 article in Science provocatively observe, “If pollution can affect reasoned judgment and decision-making . . . then perhaps every aspect of daily living may be altered by our contaminated environment.”[12]

·      The Epigenetics of Fear and Anxiety—There is growing scientific evidence that highly stressful or traumatic events can cause epigenetic changes in parents that may be passed on to their children and even grandchildren, predisposing them to be depressed or anxious.[13] If this is true, how might the widespread experience of warfare during WWII and after—most especially on the battlefield, but perhaps also fears raised on the home front—have affected the cognitive nature of people? For example, should we understand the American fears of atomic Armageddon in the fifties and sixties, from “duck and cover” to backyard fallout shelters, as having physiological consequences that contributed to cultural changes?

·      Distancing From Rural Animals—Rather than trying to take on all of the vast array of material changes associated with the movement of many of the globe’s people from rural to urban environments, the project will focus on the question: What physiological and cognitive changes might have occurred as a result of the rapid decline in physical interactions between people and domestic animals like horses, cows, pigs, and chickens? If, as Edmund Russell has demonstrated, humans had co-evolved with these animals for millennia, it seems possible that their sudden absence from the lives of many people had significant physiological and cognitive effects.[14]

·      The Effects of Virtuality—As many people became increasingly entangled in technologically mediated networks of communication, work, and recreation—from telephones to video games and the internet—how did this growing immateriality of their daily existence change the way they felt and thought? As the Yale historian Timothy Snyder has recently argued, the increasingly virtual nature of contemporary online discourse threatens to undermine our ability to accurately understand and shape the real material world.[15]

·      The Physiology of Speed—How did the increasingly common experience of speedy automobility, and subsequently the even greater speed of mass air travel, affect the ways in which many post-war humans felt and thought?[16]

 The “New Post-War Human” project is in the preliminary stages, so the first task will be to investigate these topics and draw on the secondary literature to chart the extent and nature of the material changes in question. Depending on these results, the second task will be to investigate three or four of the most promising topics in depth and attempt to provide a descriptive history of their material nature and how these material changes translated into any significant organismal changes in a significant cross-section of humans, if at all. A preliminary search suggests that there are considerable resources to be found in the scientific and social science literature, both contemporary and historical.[17] Bringing this material together in an accessible format will in and of itself be an invaluable historical contribution, as this history has rarely been approached on these terms. Finally, if there are some positive results—i.e., evidence of significant physiological changes in post-war humans—the third and most challenging task would be to consider how the shifts in the organismal nature of the species might have influenced the course of post-war history. Importantly, I would not anticipate that such physiological shifts would in any sense be determinative. Rather, it seems likely that these would add to and help to better elucidate other more traditional causal historical factors, offering a more rounded and materially rooted view of the period.

[1] See for example R. G. Collingwood, The Idea of History (Mansfield Center, CT: Martino, [1946] 2014). These assumptions are examined and challenged in Dipesh Chakrabarty, “The Climate of History: Four Theses,” Critical Inquiry 35 (Winter 2009): 197-222.

[2] Julia Adeney Thomas, “History and Biology in the Anthropocene: Problems of Scale, Problems of Value,” American Historical Review 119 (2014), 1587-1607, quotes on 1601.

[3] J. R. McNeill and Peter Engelke, The Great Acceleration: An Environmental History of the Anthropocene since 1945 (Cambridge, MA: Harvard University Press, 2014).

[4] Will Steffen, Jacques Grinevald, Paul Crutzen, and John McNeil, “The Anthropocene: Conceptual and historical perspectives,” Philosophical Transactions of the Royal Society 369 (2011): 842-867, see especially pp. 849-852.

[5] Some notable recent exceptions regard the history of the mind and neurohistory. See: Daniel Smail, Deep History and the Brain (Berkeley, CA: University of California Press, 2007), and, Edmund Russell, ed., Environment, Culture, and the Brain: New Explorations in Neurohistory (RCC Perspectives, 2012).

[6] Timothy J. LeCain, The Matter of History: How Things Create the Past (Cambridge, UK: 2017), see especially 124-36.

[7] Ann Reid and Shannon Greene, Human Microbiome: A Report From the American Academy of Microbiology, (Washington, DC: American Academy of Microbiology, 2013); Timothy G. Dinan, Catherine Stanton, and John F. Cryan, “Psychobiotics: A Novel Class of Psychotropics,” Biological Psychiatry 74 (2013): 720-726; and Thomas, “History and Biology in the Anthropocene,” 1587-1607.

[8] Daniel F. Simola, Riley J. Graham, et al., “Epigenetic (re)programming of caste-specific behavior in the ant Camponotus floridanus,” Science 351 (January 2016).

[9] Kevin Laland, Tobia Uller, et al., “Does evolutionary history need a rethink? Yes, urgently,” Nature 514 (2014): 161-164.

[10] Andy Clark, "Where Brain, Body and World Collide," in Material Agency, Carl Knappett and Lambros Malafouris, eds., Material Agency: Toward a Non-Anthropocentric Approach (New York: Springer, 2008).

[11] Martin J. Blaser, Missing Microbes: How the Overuse of Antibiotics is Fueling Our Modern Plagues (New York: Henry Holt and Company, 2014).

[12] Joshua Graff Zivin and Matthew Neidell, “Air pollution’s hidden impacts: Exposure can affect labor productivity and human capital,” Science 359 (2018): 39-40.

[13] Rachel Yehuda, Nikolaos P. Daskalakis, et al., “Holocaust Exposure Induced Intergenerational Effects on FKBP5 Methylation,” Biological Psychiatry 80 (2016): 372-80.

[14] Edmund P. Russell, Evolutionary History: Uniting History and Biology to Understand Life on Earth (Cambridge, UK: Cambridge University Press, 2011).

[15] See, for example, Snyder’s recent podcast, “Cybercolony USA,” available at:

[16] Mimi Sheller, Aluminum Dreams: The Making of Light Modernity (Boston: MIT Press, 2014.)

[17] For example, the well-recognized effects of socioeconomic status on childhood brain development: D. A. Hackman and M. J. Farah, “Socioeconomic status and the developing brain,” Trends in Cognitive Science 13 (2009): 65-73, and, Kimberly G. Noble, Suzanne M. Houston, et al., “Family income, parental education and brain structure in children and adolescents,” Nature Neuroscience 18 (2015): 773-778.