Young adults in the U.S. increasingly accept evolution by natural processes

5 minute read

After many years of stasis, the acceptance of evolution has taken a noticeable uptick for American adults. Most of this increase comes from the change in young adults 18 to 29 years of age.

Since its 2014 survey of the U.S. public, the Pew Research Center has issued many press releases and interactive features about its findings concerning public attitudes toward science topics. I’m actually quite amazed at the sheer number of press releases they roll out, targeted individually at every religion and issue.

The 2014 Pew survey results are reported on their website: “Americans, Politics and Science Issues”. With respect to the evolution questions, the survey results show a strong association between evolution acceptance and lower age, and between evolution acceptance and lower religious attendance. Other demographic factors had associations of medium strength with evolution acceptance, including political party affiliation, gender, and education.

The evolution results are not breaking news, but I was prompted to write by an article in Slate by Rachel Gross, which especially emphasizes the recent growth in evolution acceptance among young adults: “Evolution Is Finally Winning Out Over Creationism”.

This increase among young adults first was noticed in the results of a 2013 Pew Research Center survey, and continued in a 2014 survey. In the more recent survey, a slight majority (51%) of adults ages 18-29 agreed with the statement that humans and other living things have evolved over time by natural processes such as natural selection. A much greater majority, 73%, agreed that humans have evolved over time, and have not been in their present form since the beginning of time.

Any survey is tricky to interpret, especially because the way a question is worded can make a difference to the way people respond. The Pew survey asks its respondents about many different scientific topics, nearly all of them related to public policy, such as genetically modified organisms, climate change, and the space program. As far as evolution is concerned, the survey has included the same questions for many, many years, so at least we can see whether there are trends over time. The most obvious trend is the large increase in the acceptance of evolution among the youngest age cohort.

I quite like this figure available from the Pew website. It shows the result of one of the evolution survey questions across the age groups, and in comparison with the membership of the American Association for the Advancement of Science.

Pew evolution survey results
Pew survey results in groups with different ages. Bars indicate percent who agree that humans have evolved over time, without regard to whether evolution was by natural processes or divine guidance.

Happily, 98% of AAAS members agree that humans have evolved over time. Only 65% of the general public agree with this statement—with the gap shown by the bar at the top of this graph. But 73% of young adults agree, compared to only 54% of adults over 65 years old in the survey.

Science knowledge and educational attainment both correlate with evolution acceptance in the survey, although neither correlates as strongly as religious attendance. Still I can’t help but think that much of the increase in acceptance of evolution in particular must go along with an increase in science knowledge by younger adults:

Pew evolution education results
Percent who agree that humans have evolved over time, either by natural processes or with divine guidance, in groups with different levels of overall science knowledge.

In this, I have a similar intuition as the geneticist Sean B. Carroll, who wrote about the results of the previous 2013 Pew survey: “Is America Evolving on Evolution?”:

[A]n additional possibility that we in the science education profession would like to entertain is that today’s young-adult generation has received the most and best information about evolution. The last few decades have been a golden era for evolutionary science, from discoveries in the fossil record to the mining of DNA to reveal how evolution works at the molecular level. And over the past decade the concerted efforts of various academic and scientific organizations have led to greater emphasis in textbooks and curricula on the central place of evolution in understanding life.

Human evolution has become more vivid and interesting within the last 10 years. The increasingly widespread genetic sampling of the world’s peoples has demonstrated the recent evolution of our species, including the effects of natural selection during the past 10,000 years since humans invented agriculture and civilization. Ancient DNA evidence has expanded our knowledge of our genetic relationships to even more ancient populations, including the Neandertals. Those classic representatives of “extinct” humans are not fully extinct but instead contributed to the ancestry of living people. We can find their genes within living people, so that every month seems to bring a new discovery of how evolution within modern humans has changed our biology.

Meanwhile, paleoanthropologists have made stunning fossil discoveries.

In the last ten years, we’ve had the first publications of two skeletons of Australopithecus sediba, of one skeleton of Ardipithecus ramidus, new material of Australopithecus afarensis including a partial skeleton, new postcranial remains and a new skull of Homo erectus from Dmanisi, new remains of Homo rudolfensis and Homo habilis, a raft of new hominin material from Sima de los Huesos, and of course this year, Homo naledi. And I’m leaving many out! Just this week, a new skull of Homo erectus.

The avalanche of new fossil discoveries means that since the turn of the century, if we look beyond modern human and Neandertal remains, the fossil record of hominin evolution has grown by nearly a third.

In the face of such a relentless pace of discovery, advocates of creationism are failing to persuade young people that scientists have no evidence of our evolution. The evidence is within all of our cells, in billions of base pairs of information.

Human evolution is no longer a theoretical exercise in many classrooms. Students are browsing actual genome data to see the parts that have evolved. Teachers are printing their own casts from fossil data. These technologies make it possible for us to take the rich legacy of our evolution and make it visible for students. The strength of the evidence has made human evolution more and more important to biology education.

That’s good news for biology. After many decades in which laboratory biologists might work without much use of applied evolution, applying genomics has made the principles of evolution have more and more important to biological discovery. Evolutionary ideas have greater practical importance in medicine, agriculture, and pharmaceutical development than ever before.

It’s also good news for society. The twenty-first century is the age of biology, a time during which humans will apply technology to change nature and ourselves. Understanding how human populations can evolve will be important for many of the questions we face in the future.