Making Sense of Biology
Nothing in Biology Makes Sense Except in the Light of Evolution, Theodosius Dobzhansky. (1973). The American Biology Teacher, 35(3), 125-129.
Two hundred years after the birth of Charles Darwin and one hundred and fifty years after the publication of On the Origin of Species the majority of Americans do not accept organic evolution. How can this be? They disbelieve in evolution despite the overwhelming evidence demonstrating the falseness of special creationism and supporting the unity of life via descent with modification. If we are to comprehend this phenomenon, we must look to Dobzhansky’s essay in The American Biology Teacher. The title states: “Nothing in biology makes sense except in the light of evolution.” If we accept the notion that humans are biological organisms and that therefore their behavior has its roots in our biology, then we can understand how so many people in an advanced industrial nation can still reject evolution. Specifically, we must examine how people come to believe anything and how this process in the human mind is itself strong evidence that our species evolved.
Over the last 30 years or so the Gallup Poll has consistently queried Americans concerning their views of evolution and creation. Particularly instructive are the results from the question that asked whether humans were the result of a special act of creation by a supreme, supernatural being (God): Creationism, that is, the idea that God created human beings pretty much in their present form at one time within the last 10,000 years is definitely true. In 2008, 44% of those who responded said that this was definitely true. The numbers have run between 47 – 43% between the years 1982 – 2008. Those who felt that humans developed but that God guided the process has run between 40 – 35% in those same years and finally those who felt that humans developed without God guiding the process have varied between 9 – 14% over those years (Gallup Poll 20091.) This same poll found that in September 2005, 53% of Americans agreed with the statement: “God created man exactly how the Bible described it.”
These data are alarming. Modern scientific research has established beyond any reasonable doubt that life on this planet evolved, including humans. Therefore, no one in modern society who consistently employs rational thinking should accept the idea that humans appeared at the result of a miraculous special creation event. Sociological research indicates that certain education, class, and geographic factors correlate with adherence to creationist views in the United States. However, with 53% of Americans agreeing to the Biblical version of creation, this cannot be solely a function of education and class. Something else is going on here. This is best explained by the irrational character of the human mind and the inability and unwillingness of our educational system to address this problem.
The imperfect mind
One of special creationism’s favorite saws against evolution is what Darwin described in The Origin as “organs of extreme perfection.” Examples in their literature abound, such as the human eye or brain. Their fundamental error is in claiming that any human organs are perfectly or even well-designed. In the case of the human brain, no better case against perfection can be cited. The human brain developed over millions of years of animal evolution. Yet, all popular notions to the contrary, biological evolution does not produce perfect organs. Evolution is always constrained by past history, so it makes incremental improvements over previously existing organs and structures. However, improvement at one thing, are not always improvements at everything. Neurological and physiological capacities which are optimal for interpreting some kinds of sensory input and making decisions concerning them develop at the expense of others forms. For example, we see in a very narrow spectrum of light wavelengths from 400 nm (deep blue, a nanometer is 10-8 meters) to 700 nm (deep red.) We can’t see long radio waves (108 meters), short radio waves (1 meter to 10-4 meters), microwaves (10-2 – 10-4), infrared (10-4 – 10-6), ultraviolet (10-8 – 10-9), x-rays (10-8 – 10-12), or gamma-rays (10-11 – 10-16.) Certainly, if the human brain and nervous system were perfect, they should have been able to see these sources of radiation without the aid of instrumentation. Yet we cannot, and just in case you think it is impossible to see in the rest of the spectrum, many insect species can see in the ultraviolet. Neither can the human brain navigate via the earth’s magnetic fields. This is a feat that pigeons and other migratory birds can accomplish with relative ease.
These examples may not seem entirely relevant to human experience. However there are several examples of the natural fallacies which result from the way the human brain functions, such as optical and cognitive illusions. Color constancy is well known from psychological experiments. In this case, people see objects as a certain color because they believe that they are supposed to be that color (even when they are not that color.) Size constancy occurs when objects pass us and move into the distance. The actual image formed on our retina gets smaller, but our brain compensates and tells us the object is still the same size as when we saw it up close. Size constancy is learned, we are not born capable of doing this. The Ba Mbuti pygmies did not know size constancy because they lived in thick jungles were objects were always only a few feet away. When these individuals were taken to a plain and saw buffalo grazing in the distance, they asked the researchers what kind of insects they were observing2. Another example of this can be observed from Piaget’s classical experiments with children and the conservation of matter. Young children were asked which container held more liquid (a long narrow one or a short wide one.) The rub was that both containers had the same volume, yet the children always identified the tall, narrow container as having more liquid. They did this even after they were shown that both containers had the same amount of liquid.
Human memory is now known to amazing unreliable, especially in cases of trauma. This has now thrown tremendous doubt on the validity of eye-witness testimony in criminal cases involving violent crime. A well-known recent example of this is illustrated by the case of the Virginia freeway snipers. Witnesses claims that they saw shots fired from a white van and that two “white” men sped away after one of the shootings. The certainty associated with the witness identifications follows from a deeply held preconception (based on empirical data.) So far, in American society, most serial killers have been European American men. In actuality the freeway snipers drove a Blue Chevrolet and were African American men. Tragically, when Lee Malvo called the police tip lines to demand an extortion payment to end the shooting, the police ignored the call because they determined that the caller was African American3.
The human brain’s activity can also be altered by chemical substances and other toxins. A classical example of this is how the brain reacts to the drug LSD (lysergic acid diethylamide.) LSD is a compound produced by the Ergot fungus which often grows on rye. LSD causes a dream-like state, including dizziness, hallucinations, weakness, nausea, lack of self-control, and in some cases extreme terror. It is still debated whether a case of mass ergot poisoning occurred in Pont St. Espirit, France in August 1951. Ergot contaminated rye was used to make bread at a local bakery, a mass outbreak of hysteria occurred in those who eat the bread, leading to four deaths. Many claimed they were demonically possessed, and eventually an exorcism was performed at the bakery in question. The scientific debate concerning the Pont St. Espirit case revolves around whether it was LSD from the rye or poisoning caused by a mercurial based pesticide used to treat the rye before it was harvested. Historians also suspect that ergot poisoning played a role in the Salem witch trials hysteria of the Massachusetts Colony in 1692. Finally, it is argued that Ergot poisoning killed 20,000 people (1/2 population) of the Aquitaine region of France between 944-45 AD4.
Humans clearly learned about the pharmacological properties of many plants early in our history. For example, Mesoamerican shamans utilized peyote to enter trance-like states and receive visions. The Aztecs also used the seeds of the morning glory plant. The morning glory plant belongs to the deadly nightshade family which contain at least three powerful alkaloids, pyridine, steroid, and tropane. The American Indians were using tobacco when the European colonists arrived (tobacco is a nightshade.) In addition to drugs, physiological stress can also cause hallucinations. Powerful hallucinations can result from lack of water, sleep, or hunger. A common theme found in religious narratives worldwide involves people wandering without food, water, or sleep to receive spiritual visions5. It has also been shown experimentally that “out-of-body experiences” can be generated by stimulating the posterior portion of the superior temporal gyrus. In the out-of-body experience, patients describe seeing their body from an elevated and distanced prospective6. Out-of-body experiences have also been described by patients with tinnitus and epilepsy. Some have claimed that out-of-body experiences are proof positive of the existence of the spiritual world. These experiments logically demonstrate that this claim is not necessarily true, since the experience can be generated by entirely natural means.
Finally, many disease states can cause altered senses of reality. One of the most well known is schizophrenia. Schizophrenics will see and hear things that are not present. John Nash, the Nobel Prize winning mathematician suffered from schizophrenia, as did David Berkowitz, the serial killer dubbed: “The Son of Sam.” The success of the American Revolution was in part caused by the fact that the English King George III suffered from porphyra. Porphyra is a genetic disease in which copper metabolism is impaired. Porphyra was common amongst the royal families of Europe, and causes urine to be colored blue (hence the term “blue blood.”) A side effect of this disease is impaired mental function, including what is called “insanity.”
Evolutionary legacies also influence how our brain copes with the modern world. First, we did not evolve an organ that has infinite memory. We do not possess high fidelity memory in the way that computers do. Our brains have to locate memories within a specific context, as opposed to utilizing all of our experiences in an unbiased way. Furthermore, our brain is capable of two types of thinking, reflexive and deliberate. The reflexive type, evolved earlier, and governs most of our behavior. The reflexive system can quickly assess statistics, such as the likelihood that a person with a given set of features is likely to be dangerous7. However, it is therefore prone to making hasty generalizations (which are informal logical fallacies.) The deliberative system, on the other hand, is slower, and is capable of greater logic (and this ability is strongly influenced by training.) Clearly, we would make fewer errors in either our judgments of phenomena in the natural and social world, if we made more use of our deliberative systems8. The problem, of course is that reflexive system often supplies the deliberative system with inaccurate data for it to make judgments. For example, humans tend to believe that whatever is familiar is good. This leads us to further believe that whatever social policies that are in place, must be good. The experimental evidence strongly supports this assertion. One such experiments asked subjects if feeding ally cats was good (one group was told it was legal, the other that it was illegal) or experiments in which students were asked how many hours of instruction should be given for a particular course. In each case, there was a statistically significant difference in the favor of the existing policy. This phenomenon can easily explain the persistence of religious views of nature. What is worse is that when humans feel threatened, our tendency to cling to the familiar is pronounced9. It is clear that politicians have realized this feature of human behavior for some time. The Nixon administration coined the modern Republican strategy of pandering to the fears of European Americans against the social advancement of African Americans. In 1972, this helped Nixon win the largest mandate of a presidential candidate in history up to that point10.
How does our imperfect brain explain widespread belief in creationism?
While the practice of critical thinking is made possible by the structure of the human brain, most people never develop or employ such skills in their lives. Unfortunately even those that do develop critical ability do not always apply it in all aspects of their thinking11. Why is this so? My answer to this quandary will be shocking for some. However, the root of the failure lies in fact that not enough people are encouraged to practice these skills and to mature them to the level required to be effective thinkers. This in turn occurs because of the nature of human social structure, particularly social dominance hierarchies. Such hierarchies are the result of evolutionary processes, engaged in my individuals and groups to control access to resources. Throughout our history, control of resources leads to happier, more comfortable, disease-free lives and such circumstances increased the likelihood of individuals reproducing children who survived to reproductive age. For example, the poorest nations in the world reside on the African continent. Sierra Leone has an infant mortality of 169 per 1,000 live births compared to France or Germany which show only 5 per 1,000 live births. The gross domestic product per capita of Sierra Leone is only 900 dollars per year compared to > 31,000 dollars per year in France and Germany. This comparison is important because the development of European industry was made possible in part by their past colonial exploitation of African resources and labor. Their past colonial domination of Africa was in turn made possible by their greater military-industrial complex and maintenance of colonial rule in Africa was facilitated by the denial of education to the colonized Africans. Chattel slavery in America operated under similar procedures. The slave holding states made it a crime to teach slaves how to read. Thus by controlling their minds it was easier to control their bodies.
One could argue that the previous examples do not explain the preponderance of non-critical thinking in a modern industrial country such as the United States. However, it would be hard to imagine how the existing social inequities in our nation could continue to exist if the majority of our population were critical thinkers. Critical thinkers contain a variety of attributes which are antithetical to the social domination of others. The attributes of such individuals are thought to include analytical skills, effective communication, research and inquiry skills, flexibility and tolerance for ambiguity, open-minded skepticism, creative problem solving, curiosity, and engage in collaborative learning, and consider the perspectives of all-stakeholder groups in issues12. Charles Darwin employed some of these techniques when he concluded that slavery was in intolerable evil, despite the widespread belief amongst Europeans in the inferiority of non-Europeans and that this justified their enslavement to serve the ends of European nations13. In the modern context, it would have been impossible for Alaska governor Sarah Palin to have become as popular as she was in the 2008 electoral contest if critical thinking was widespread in this country. Palin is a religious fundamentalist who is opposed to birth control, abortion, and the teaching of evolution in the public schools. Thus if the majority of Americans never develop critical thinking skills, it is not hard to understand how 53% accept the claim that humans were created according to a literal interpretation of the Bible (Genesis.) If so, which literal interpretation are they agreeing to? The one in Genesis 1 in which the order of creation is seed-bearing plants, aquatic creatures, flying birds, land creatures, and Adam and Eve are created simultaneously out of the dust of the ground or Genesis 2 in which the order of creation is Adam, trees in the garden of Eden, beasts of the fields, birds of the air, and Eve out of Adam’s rib. Aquatic creatures are not mentioned in Genesis 2. Logically, both cannot be true, and if both cannot be true, how is it possible to read the Bible literally?
Even amongst people that do develop general critical thinking skills, it is possible for them to question organic evolution, due to lack of discipline specific knowledge. An appallingly small percentage of American high school students receive focused instruction in evolutionary biology14. In a large national survey of high school teachers, the most common percentage of coverage was 1 -2 hours for human evolution (35%) and on general evolutionary processes 6 – 10 hours were covered by 26% of the teachers surveyed. Given Dobzhansky’s dictum these numbers are way out of line. In that same study, teachers reported significant external pressure to not cover evolution. In addition, the majority of American college students do not take classes in biology, let alone evolutionary biology or anthropology. This leads to college students adopting a number of uncritical and uninformed attitudes toward biological organisms, especially humans15. For this reason at my institution we have incorporated evolutionary concepts in a number of our general education courses. These courses apply general critical thinking skills to address the theories which purport to explain the diversity of life (special creationism, transformationism – Lamarckian evolution, and descent with modification—Darwinian evolution.)
A Nation Still at Risk
In 1983 we were warned that other nations were matching and surpassing our educational achievements and that our educational system was miring in mediocrity16. In 2002, not much had changed. The performance of American students in mathematics and science was still declining relative to the rest of the industrialized world. Leaders in higher education began to call for a new emphasis on critical thinking in the curriculum K – 2017. Do they really know what they are asking for?
If we were to truly emphasize critical thinking in the biology, chemistry, and physics curricula, then the majority of Americans educated in the public schools would begin to seriously question the legitimacy of special creationism. Indeed, this might be an important metric illustrating that critical thinking applied in the sciences was actually succeeding. In addition to the sciences, critical thinking widely practiced would severely threaten American social practice. For example, the widespread an ongoing denial of basic human and civil rights to gay/lesbian or transgendered Americans would fall. In addition, social constructions of race would no longer continue to confuse us18. We would no longer be content with allowing a small elite group of greedy and immoral individuals to determine how we should live, what food we should eat, what energy sources we should use. Taken to its logical end, critical thinking may be the most dangerous threat to the status quo that has ever existed. This is precisely why as an evolutionary biologist, I champion it.
Notes and References
- Schick, T. and Vaughan, L., How to Think About Weird Things: Critical Thinking for a New Age, (New York, NY: McGraw Hill), 2005, pp. 38-39.
- Leyton, E., Hunting Humans: The Rise of the Modern Multiple Murder, (New York, NY: Running Press, 2005) and Johnson, D. and Van Nitta, D., Retracing the trail: The investigation; miscues in sniper pursuit, then calls and a big break, The New York Times, October 27, 2002.
- Burgen, A., St. Anthony’s Gift, European Review no. 11: 27-35, 2003; Shiff, P.L., Ergot and its alkaloids, Am. J. Pharm. Education, 2006.
- The gospels tell of Christ wandering in the desert for 40 days and 40 nights.
- De Ridder, D.E., Van Laere, K., Dupont, P., and Van de Heyning, G., Visualizing the out-of-body experience, The New England Journal of Medicine 357:18, 1829-1833, 2007.
- There is an interesting experiment being conducted that addresses this topic at http://backhand.uchicago.edu/Center/ShooterEffect/. In this experiment, you are asked to push a key on your keyboard to determine whether you should shoot a person holding a gun, or holding a non-threatening object. The images are of African American and European American men who are presented in different contexts. This experiment tests the user’s reflexive system, in that you may either correctly/incorrectly shot an African American holding a gun/non-lethal object, European American holding a gun/non-lethal object. The operational hypothesis of this experiment is to test whether a person’s racial socialization impacts their reflexive response to the images. Thus, we might predict that a European American may be more likely to shoot an innocent African American, and not shoot a threatening European America, or vice versa.
- Marcus, G., Kluge: The Haphazard Construction of the Human Mind, (Houghton Mifflin), 2008 and Linden, D., The Accidental Mind: How Brain Evolution Has Given Us Love, Memory, Dreams, and God, (Belknap Press), 2007.
- Marcus, G., Kluge: The Haphazard Construction of the Human Mind, (Houghton Mifflin), 2008 pp. 41-51.
10. Mayer, J.D., Running on Race: Racial Politics in Presidential Campaigns: 1960 – 2000, (New York, NY: Random House), 2002, pp. 97-122.
11. Royalty, J., The generalizability of critical thinking: Paranormal beliefs versus statistical reasoning, J. General Psychology 156(4): 477-488.
12. Boss, J., Critical Thinking and Logic Skills for Everyday Life, (New York, NY: McGraw-Hill), 2010 or Moore, B. and Parker, R, Critical Thinking, 9th ed., (New York, NY: McGraw-Hill), 2009.
13. Desmond, A. and Moore, J, Darwin’s Sacred Cause: How a Hatred of Slavery Shaped Darwin’s Views on Human Evolution, (New York, NY: Houghton-Mifflin), 2009.
14. Berkman MB, Pacheco JS, Plutzer E (2008) Evolution and creationism in America’s classrooms: A national portrait. PLoS Biol 6(5): e124. doi:10.1371/journal.pbio.0060124.
15. Graves, J.L. and Bailey, G.L., (in press) Evolution, Religion, and Race: Critical Thinking and the Public Good, Forum on Public Policy: A Journal of the Oxford Round Table.
16. The National Commission on Excellence in Education, A Nation at Risk: The Imperative for Educational Reform, United States Department of Education, 1983.
17. American Association of Colleges and Universities, College Learning for the New Global Century, a Report for Liberal Education and America’s Promise, AAC&U, 2007.
- Graves, J.L., The Race Myth: Why We Pretend Race Exists in America, soft cover edition with a new preface by the author (New York, NY: Dutton Books), 2005.