Darwin Pushed to Margins

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Despite winning court battles at every turn, advocates for teaching evolution as the unshakable bedrock of high school biology courses have been losing on the ground to an astonishing degree.

In a recent essay in Science, Penn State political scientists Eric Plutzer and Michael B. Berkman reported that their survey of U.S. public high school biology teachers show that only a relative small minority unambiguously teach the mainstream scientific view of evolution. Only 28 percent of the 926 instructors surveyed consistently implement the recommendations of the National Research Council, which calls on high school biology instructors to present without qualification the overwhelming evidence for evolution. About 13 percent of these public school instructors are active advocates for creationism or Intelligent Design as “valid scientific alternatives” to evolution — and, says Plutzer, “an additional five percent of teachers take the same position, though typically in brief responses to student questions.”

Plutzer, co-author (with Berkman) of Evolution, Creationism, and the Battle to Control America’s Classrooms (Cambridge, 2010), discusses in a Big Questions Online interview more surprising facts uncovered by the survey, and their implications for science education in America.

Many assume that resistance to evolution is something largely confined to the rural South. Do the survey data indicate that the phenomenon is limited to one or more regions of the country? 

Prior to our study, there were many surveys of teachers that also pointed to widespread teaching of creationism. But these earlier studies never included studies of the California, New York and the New England states. Our national probability sample of teachers confirmed what several scholars had suspected, that active proponents of creationism as science can be found in every state, even in fairly cosmopolitan school districts. Skepticism about evolution can be found all over the country, and many future teachers begin their education as evolution deniers. Those with strong feelings are unchanged by their college science education and bring these feelings to their classrooms.

What role does the local community play in the kind of biology taught in their public high schools?

The local community plays several important roles, and perhaps the most important is in the hiring and retention of teachers. We found that (on average, of course) teachers who do not accept human evolution tend to find jobs in the most socially conservative districts. Thus many teachers share values with their communities and find it easy to teach in accord with those values. Of course, “mismatches” are quite common, and teachers who find themselves at odds with local sensibilities may try to leave or fit in as best they can without stirring up controversy.

However, fitting in and avoiding controversy is not always possible. Many communities have large pro- and anti-evolution constituencies. We found that the teachers who experienced the most pressures to teach in a particular way were those in school districts with both a large number of doctrinally conservative Protestants and a large number of highly educated citizens. In these districts, there is no easy path for teachers to teach in accord with local opinion because local opinion is polarized.

Perhaps the most striking finding is that 60 percent of the nation’s public high school biology teachers are trying to take the middle ground on the evolution-vs.-creation issue. In your Science article, you and your co-writer speculate that this “cautious 60% may play a far more important role in hindering scientific literacy in the United States than the smaller number of explicit creationists.” Explain.

Like their students, teachers want to avoid being called into the principal’s office, and teachers are very good at anticipating when a classroom topic is likely to stimulate a complaint from a parent or a school board member. Teachers know their communities well. On the other hand, teachers have strong professional norms and would like to teach with integrity and in accord with the recommendations of the major scientific organizations, even if it means ruffling some feathers. Teachers with considerable education in evolutionary biology tend to be confident that a visit from a parent or a complaint from a school board member will turn out well. One teacher reported to us that he was asked to write a “a letter explaining my view on why I teach Evolution through Natural Selection but not by ID. That was good enough for my principal.” But teachers with less extensive science education and with less confidence in their own expertise tend to play it safe.

They do this in a number of ways. Many sharply curtail the amount of class time devoted to evolution and focus solely on the “microevolution” of bacteria or small superficial changes in populations, such as in the coloration of moths. But they avoid the notion that current species have common ancestors. Others cover the material, but disassociate themselves from it by explaining that they are covering it because students need the information to pass high stakes examinations. Still others cover the material, but tell students that they can come to their own conclusions about the validity of the major findings reported in their textbooks. Each of these techniques undermines the legitimacy of science and the weight of empirical evidence.

Your study found that 13 percent of teachers explicitly advocate creationism or intelligent design. These are public school teachers, not teachers at private or religious institutions. How is this possible, given court rulings against this kind of thing?

The courts have consistently held that the teaching of “creation science” or Intelligent Design creationism represents an unacceptable violation of citizens’ rights to be free of government endorsement of specific religious tenets. The federal court system in the U.S. is not Big Brother. The Supreme Court is not in the business of identifying every instance of unconstitutional behavior. Rather, the burden on citizens is to “make a federal case of it” — literally.  If no students or parents complain, teachers are free in their classrooms to make a wide range of choices concerning content and pedagogy.

It is also important to emphasize that while courts have prohibited instruction of creationism as science, and they have voided outright bans on the teaching of evolution, they have not mandated that evolution must be taught. The range of constitutionally permitted instruction is quite large, including the enthusiastic integration of evolution into all biological topics, all the way to be silent on evolution. State boards of education can recommend any set of learning goals that fit between these two extremes.

Given that only a relative few high school students will continue on to do college-level work in biology, much less become professional biologists, why do you see this as a serious problem?

We see two distinct issues here. The first is that students are being cheated out of a sound science education. All nations are increasingly confronted with important policy choices that are informed by science: Should we mandate vaccines for all school children? Should we take costly steps to reduce carbon emissions? How can we most effectively reduce the incidence of chronic diseases?  For ordinary citizens to play a meaningful role in democracies tackling these issues, they need to be excellent critical thinkers concerning science. They should not blindly accept scientific findings, whether they come from academia, government or industry. But neither should they believe that scientific debates are simply clashes of opinion and values. A healthy appreciation of the nature of science, the persuasiveness of replication, and respect for the necessary expertise is also essential. When teachers tell their students that they can have their own opinions about the validity of evolutionary biology, they are sending a dangerous message to our future citizens.

On the other hand, the failure to integrate evolution into the general biology class represents a missed opportunity to turn students on to science. Students come to high school fascinated by dinosaurs, knowledgeable about the animals in their local ecosystems, intrigued by the “fights for survival” depicted on popular nature series on television; they know that they receive a flu shot each year, but not vaccines for measles — and they may be curious why. Although perhaps not the only way, evolution provides a way to address fascinating “why” questions throughout the academic year that can complement the more dreary topics like the memorization of the names of the parts of the cell.

Evolution also is a great way to convey to students the messiness and excitement of science. Indeed the history of evolutionary biology is much like a TV drama. Darwin’s inference of common ancestry was based on his heroic analysis of comparative anatomy and selective breeding. He knew of many fossils, but lacked a scientific basis to date them. But with the advent of radio chemistry and advances in the geosciences, it later became possible to date fossils and the rocks in which they were discovered. And these findings led paleontologists to the conclusion of common ancestry as well. Later still, genomics allowed scientists to construct phylogenic trees without considering anatomy or fossils. These studies differed in the details (a constructive difference leading to new research) but also confirmed the notion of common ancestry. It is exactly like an episode of CSI in which the fingerprint technician, the DNA analyst, and the tech identifying the chemical residue on the victim’s shoes all burst into Grissom’s office and name the same suspect! Evolutionary biology — taught well and thoroughly — offers a great opportunity to convey the nature of science to young people. This is an opportunity most school children are denied.

What can be done to remedy the situation, especially considering your finding that one out of three creationism advocates have taken a course on evolutionary biology, and have rejected what they’ve been taught?

First, we want to be clear that that current efforts by the scientific community are important. Scientists need to be involved in court cases when they arise, need to be involved in the designing of state content standards and high stakes examinations, and need to continue to provide support to current teachers.

But these efforts are clearly insufficient. As a first step, we recommend that teacher education programs make sure that the biology side of the program is as rigorous as the instruction on classroom management and pedagogy and include a semester long course on evolutionary biology. We do not believe such a class will have much of an impact on the 13 percent of teachers who advocate creationism. But it will provide essential background to, and increase the confidence of, many of the cautious 60 percent, thereby improving instruction in thousands of classrooms.

Our research also points to another possible opportunity. We estimate that no more than 30 percent of Americans belong to faith traditions that emphasize a strict and literal reading of the Bible that may lead adherents to see a potential conflict between their faith and the findings of evolutionary biology. The contradictions are rooted in beliefs about the antiquity of the earth, Adam and Eve, and the idea that all current animals descend from those on Noah’s ark.  Probably, the actual number is far fewer than 30 percent because many churches with their roots in the early Fundamentalist movement can accommodate some figurative passages in the Bible. Nevertheless, these ideas have diffused into the larger population and are held by others whose own pastors, priests and rabbis see no inherent contradiction between scripture and science. I think there are opportunities for those associated with these other faith traditions to better articulate how faith accommodates modern science, and vice verse. These positions have been eloquently made by Francisco Ayala, Kenneth Miller, and other scientists. But the challenge has not been taken up as effectively in the mass media or in individual congregations. We see an opportunity for greater accommodation and this would mean that more students would enter their high school biology class with an open mind.

More broadly, many people of faith are drawn to the study of evolution to explore God’s work, and find a spiritual connection in their study of nature. This perspective was common in the 19^th and early 20^th centuries, but is not often enough articulated in current debates about evolution. Maybe that is because nobody has yet stated it more eloquently than Darwin himself:

There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.