According to a new Pew Research Center analysis, six-in-ten Americans (60%) say that “humans and other living things have evolved over time,” while a third (33%) reject the idea of evolution, saying that “humans and other living things have existed in their present form since the beginning of time.” The share of the general public that says that humans have evolved over time is about the same as it was in 2009, when Pew Research last asked the question.

About half of those who express a belief in human evolution take the view that evolution is “due to natural processes such as natural selection” (32% of the American public overall). But many Americans believe that God or a supreme being played a role in the process of evolution. Indeed, roughly a quarter of adults (24%) say that “a supreme being guided the evolution of living things for the purpose of creating humans and other life in the form it exists today.”

These beliefs differ strongly by religious group. White evangelical Protestants are particularly likely to believe that humans have existed in their present form since the beginning of time. Roughly two-thirds (64%) express this view, as do half of black Protestants (50%). By comparison, only 15% of white mainline Protestants share this opinion.

There also are sizable differences by party affiliation in beliefs about evolution, and the gap between Republicans and Democrats has grown. In 2009, 54% of Republicans and 64% of Democrats said humans have evolved over time, a difference of 10 percentage points. Today, 43% of Republicans and 67% of Democrats say humans have evolved, a 24-point gap.

These are some of the key findings from a nationwide Pew Research Center survey conducted March 21-April 8, 2013, with a representative sample of 1,983 adults, ages 18 and older. The survey was conducted on landlines and cellphones in all 50 U.S. states and the District of Columbia. The margin of sampling error is +/- 3.0 percentage points.

Differences by Religious Group

A majority of white evangelical Protestants (64%) and half of black Protestants (50%) say that humans have existed in their present form since the beginning of time. But in other large religious groups, a minority holds this view. In fact, nearly eight-in-ten white mainline Protestants (78%) say that humans and other living things have evolved over time. Three-quarters of the religiously unaffiliated (76%) and 68% of white non-Hispanic Catholics say the same. About half of Hispanic Catholics (53%) believe that humans have evolved over time, while 31% reject that idea.

Those saying that humans have evolved over time also were asked for their views on the processes responsible for evolution. Roughly a quarter of adults (24%) say that “a supreme being guided the evolution of living things for the purpose of creating humans and other life in the form it exists today,” while about a third (32%) say that evolution is “due to natural processes such as natural selection.”

Just as religious groups differ in their views about evolution in general, they also tend to differ in their views on the processes responsible for human evolution. For instance, while fully 78% of white mainline Protestants say that humans and other living things have evolved over time, the group is divided over whether evolution is due to natural processes or whether it was guided by a supreme being (36% each). White non-Hispanic Catholics also are divided equally on the question (33% each). The religiously unaffiliated predominantly hold the view that evolution stems from natural processes (57%), while 13% of this group says evolution was guided by a supreme being. Of the white evangelical Protestants and black Protestants who believe that humans have evolved over time, most believe that a supreme being guided evolution.

Views About Evolution by Party Affiliation

There are sizable differences among partisan groups in beliefs about evolution. Republicans are less inclined than either Democrats or political independents to say that humans have evolved over time. Roughly two-thirds of Democrats (67%) and independents (65%) say that humans have evolved over time, compared with less than half of Republicans (43%).

The size of the gap between partisan groups has grown since 2009. Republicans are less inclined today than they were in 2009 to say that humans have evolved over time (43% today vs. 54% in 2009), while opinion among both Democrats and independents has remained about the same.

Differences in the racial and ethnic composition of Democrats and Republicans or differences in their levels of religious commitment do not wholly explain partisan differences in beliefs about evolution. Indeed, the partisan differences remain even when taking these other characteristics into account. (For more on the link between party and evolution, see our Fact Tank post.)

Views About Evolution by Demographic Group

The 2013 Pew Research survey varied the exact wording of the question about evolution to better understand public views on the issue. A random group of respondents was asked about the evolution of “humans and other living things” while others were asked about the evolution of “animals and other living things.” The survey found that the wording focus on animals vs. humans made little difference in beliefs.

Beliefs about human and animal evolution tend to vary by gender, age and education. Men are somewhat more inclined than women to say that humans and animals have evolved over time. Younger adults are more likely than older generations to believe that living things have evolved over time. And those with more years of formal schooling are more likely than those with less education to say that humans and animals have evolved over time.

About the Survey

This report is based on telephone interviews conducted March 21-April 8, 2013, among a national sample of 1,983 adults, 18 years of age or older, living in all 50 U.S. states and the District of Columbia (1,017 respondents were interviewed on a landline telephone, and 966 were interviewed on a cellphone). Interviews were completed in English and Spanish by live, professionally trained interviewing staff under the direction of Princeton Survey Research Associates International.

A combination of landline and cell random digit dial (RDD) samples were used to reach a representative sample of all adults in the United States who have access to either a landline or cellphone. Both samples were disproportionately stratified to increase the incidence of African-American and Hispanic respondents. Within each stratum, phone numbers were drawn with equal probabilities. The landline samples were list-assisted and drawn from active blocks containing three or more residential listings, while the cell samples were not list-assisted but were drawn through a systematic sampling from dedicated wireless 100-blocks and shared service 100-blocks with no directory-listed landline numbers. Both the landline and cell RDD samples were disproportionately stratified by county based on estimated incidences of African-American and Hispanic respondents.

The survey questionnaire included a split-form design whereby an additional 2,023 adults were asked a different set of questions, including the questions on animal evolution reported above. The total number of interviews conducted was 4,006. Thus, the data collection involved two simultaneous surveys; where the same question was asked on each form, the results of the two forms can be combined to yield a representative survey of U.S. adults with the full 4,006 respondents.

Several stages of statistical adjustment or weighting are used to account for the complex nature of the sample design. The weights account for numerous factors, including (1) the different, disproportionate probabilities of selection in each stratum, (2) the overlap of the landline and cell RDD sample frames, and (3) differential non-response associated with sample demographics. Statistical results are weighted to correct known demographic discrepancies, including disproportionate stratification of the sample.

The survey’s margin of error is the largest 95% confidence interval for any estimated proportion based on the total sample – the one around 50%. For example, the margin of error for the entire sample is +/-3.0 percentage points. This means that in 95 out of every 100 samples drawn using the same methodology, estimated proportions based on the entire sample will be no more than 3.0 percentage points away from their true values in the population. Sampling errors and statistical tests of significance used in this report take into account the effect of weighting. In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.