Sex, Power, and Partisanship: How Evolutionary Science Makes Sense of Our Political Divide - Hector A. Garcia 2019
The Dangers of Germs
Left, Right, and Mother Nature
A deeper look into the microbiological world inside us reveals that xenophobia among humans—which ultimately results in things like separate water fountains, race riots, or even genocide—may at least in part be related to germs. Complex organisms like human beings are actually immense networks of individual life-forms (in us, roughly 37.2 trillion),31 cells that over many millions of years of evolution have joined with other cells to form symbiotic relationships. This joining allowed single-celled organisms to merge with others to build more complex cooperative units of life that were better at surviving the microscopic biome.
It is worth noting that survival in this universe inside our bodies is a savage field of combat organized with a stunning degree of militaristic complexity. Here I provide a favorite citation from a scholar who enumerates the sophistication of both attacks and defense of the wars raging inside us and how in many ways the respective strategies have analogues in the wars fought by humans:
Military alliances (could apply to synergistic pathologies, where more than one pathogen act in concert)…suicide mission (cells that self-destruct to kill the intruder)…camouflage (coating on gram negative bacteria that inhibits recognition as foreign body by failing to provide earmarks of enemy)…wolf in sheep's clothing (could be applied to viruses which have envelope made from host cell membrane)…distress signals (chemicals released by injured and dying cells)…sabotage of communications (microbes commonly bind to cell signaling receptors on surface distorting or blocking communication…). The key to a host's defense is being able to recognize its own cells and molecules from those of the pathogen (i.e. SELF from NON-SELF). In the military context, such recognition is accomplished by wearing different uniforms.32
What is important to grasp here is that human survival is contingent not only on macro-level phenomena like mating, finding food, or not getting eaten but also on the epic microscopic wars within us. The impact of these wars on the human mind can be profound. In a way, the mind (and even our political behavior) is designed to serve the microorganisms that comprise our bodies.
The emotion of disgust, for example, is an adaptation that allows thinking, acting humans to help our cellular networks avoid pathogens. For instance, imagine what the consequences would be for a human who was unable to experience disgust when presented with feces, or rancid meat, or fruit infected with maggots. If she ate any one of those, or perhaps even handled them, she would insert battalions of hostile enemies into her biome, causing the breakdown of her biological machinery.
Here it is important to understand that much of the diseases that threaten humans are transmitted by other humans. Could fear of disease translate into fear of outsiders or even political conservatism? A large volume of research would suggest so. For instance, researchers using measures to assess perceived vulnerability to disease with questions such as “I prefer to wash my hands soon after shaking someone's hand” and “I have a history of susceptibility to infectious diseases” have found that those with higher perceived disease threat show more ethnocentrism,33 greater xenophobic attitudes toward foreigners,34 and increased willingness to stigmatize socially marginalized groups, for example obese people,35 or gays and lesbians.36
Likewise, research consistently finds that higher disgust sensitivity is related to self-placement on the Left-Right spectrum.37 One study of 31,045 men and women from 121 countries around the globe found that those who self-rated as conservative showed significantly higher disgust sensitivity than those who self-rated as liberal.38 The researchers in this study also found that among Americans disgust sensitivity predicted the intent to vote conservative—in this case for John McCain over Barack Obama in the 2008 US presidential election.
Another study measured disgust sensitivity by having subjects rate how grossed out they were by statements such as, “I might be willing to try eating monkey meat, under some circumstances,” “You see a bowel movement left unflushed in a public toilet,” and “You sit down on a public bus, and feel that the seat is still warm from the last person who sat there.” The researchers found that those with higher disgust sensitivity were more likely to see immigrants and foreign ethnic groups as less than human, as well as to score higher on measures strongly associated with political conservatism, such as social dominance orientation and right-wing authoritarianism (measures we will unpack in later chapters).39
Tellingly, much research in this area links fear of pathogens to disapproval of nonnormative sexual behaviors,40 which suggests that our sexual morality is rooted in adaptations designed to help us survive reproduction in a world filled with pathogens. The intensity of this protective disgust also appears to vary in relation to the potential risks versus benefits of sexual openness in a given environment. Canadian psychologists Mark Schaller and Daimian Murray examined epidemiological maps around the globe to determine the prevalence of diseases such as leishmania, schistosoma, trypanosoma, malaria, filaria, leprosy, dengue, typhus, and tuberculosis.41 Not only did they find that openness to experience was greater where there was less disease but also that where disease was more prevalent, women in particular showed more sexual restraint. Men's sexual openness, on the other hand, was not affected by local disease prevalence, which makes sense when you consider that women, typically on the receiving end of bodily fluids in sexual intercourse, may be at greater risk than men of contracting disease from an infectious partner. Conversely, Schaller and Murray found that in places with less infectious disease, women showed more interest in new sexual partners and more comfort with casual sex, showing a liberal-leaning openness to experience. In the same vein, another study found that the farther away people are from the equator, where the climate is hotter and home to more pathogens, the higher they are in extraversion, a trait associated with liberal voting.42 Microbiological threats, and our evolved strategies for managing them, then, have impacted our political orientations.
While research suggests that germs were a principal danger in our past, the natural world teems with dangers of many varieties, and conservatives may be more sensitive to all of them. In addition to conservatives being more closed to experience, and more sensitive to disgust, research finds that conservatives tend to be generally more fearful. When subjects are shown threatening pictures in the research lab—for instance, a spider on the face of someone showing intense fear—those with more conservative attitudes have more fearful reactions.43 These differences may be reflected in our neurology; at least one neuroimaging study has found that conservatives have larger amygdalae—an ancient region of the brain that generates defensive emotions such as fear and anger.44
Still, research continues to find that fear of other humans is strong among conservatives. One study, for example, found that when shown photos of people making ambiguous facial expressions, Republicans, far more than Democrats, will project threatening emotions like anger.45 Such findings underscore the centrality of humans as a primordial danger and point to something beyond them being carriers of communicable diseases.