GALLUP NEWS SERVICE

PRINCETON, NJ -- The majority of Republicans in the United States do not believe the theory of evolution is true and do not believe that humans evolved over millions of years from less advanced forms of life. This suggests that when three Republican presidential candidates at a May debate stated they did not believe in evolution, they were generally in sync with the bulk of the rank-and-file Republicans whose nomination they are seeking to obtain.

Independents and Democrats are more likely than Republicans to believe in the theory of evolution. But even among non-Republicans there appears to be a significant minority who doubt that evolution adequately explains where humans came from.

The data from several recent Gallup studies suggest that Americans' religious behavior is highly correlated with beliefs about evolution. Those who attend church frequently are much less likely to believe in evolution than are those who seldom or never attend. That Republicans tend to be frequent churchgoers helps explain their doubts about evolution.

The data indicate some seeming confusion on the part of Americans on this issue. About a quarter of Americans say they believe both in evolution's explanation that humans evolved over millions of years and in the creationist explanation that humans were created as is about 10,000 years ago.

Broad Patterns of Belief in Evolution

The theory of evolution as an explanation for the origin and development of life has been controversial for centuries, and, in particular, since the 1859 publication of Charles Darwin's famous The Origin of Species. Although many scientists accept evolution as the best theoretical explanation for diversity in forms of life on Earth, the issue of its validity has risen again as an important issue in the current 2008 presidential campaign. Two recent Republican debates have included questions to the candidates about evolution. Three candidates -- Sam Brownback, Mike Huckabee, and Tom Tancredo -- indicated in response to a question during the May 3 debate that they did not believe in the theory of evolution, although they have attempted to clarify their positions in the weeks since.

Several recent Gallup Polls conducted in May and June indicate that a significant number of Americans have doubts about the theory of evolution.

One such question was included in a May Gallup Panel survey:

Now thinking about how human beings came to exist on Earth, do you, personally, believe in evolution, or not?

It is important to note that this question included a specific reference to "thinking about how human beings came to exist on Earth . . ." that oriented the respondents toward an explicit consideration of the implication of evolution for man's origin. Results may have been different without this introductory phrase.

With that said, Americans' responses to this question are essentially split down the middle. About half say they do believe in evolution and about half say they do not.

A second question included in a June 1-3 USA Today/Gallup poll asked about evolution side by side with a similar question about creationism:

Next, we'd like to ask about your views on two different explanations for the origin and development of life on earth. Do you think -- [ITEMS ROTATED] -- is -- [ROTATED: definitely true, probably true, probably false, (or) definitely false]?

A. Evolution, that is, the idea that human beings developed over millions of years from less advanced forms of life

B. 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

These results are similar to those from the question asked in May. A little more than half of Americans say evolution -- as defined in this question wording -- is definitely or probably true. Forty-four percent say that it is probably or definitely false.

In contrast, even more Americans, two-thirds, say the theory of creationism is definitely or probably true.

A separate Gallup Poll trend question -- also asked in May -- gave Americans three choices about human beings' origins. Responses to this question found that 43% of Americans choose the alternative closest to the creationist perspective, that "God created human beings pretty much in their present form at one time within the last 10,000 years or so." A substantial 38% say human beings evolved, but with God guiding the process. Another 14% favored an interpretation of evolution arguing that God had no part in the process, leaving a total of 52% who say humans evolved with or without God's direction.

Which of the following statements comes closest to your views on the origin and development of human beings -- [ROTATE 1-3/3-1: 1) Human beings have developed over millions of years from less advanced forms of life, but God guided this process, 2) Human beings have developed over millions of years from less advanced forms of life, but God had no part in this process, 3) God created human beings pretty much in their present form at one time within the last 10,000 years or so]?

To summarize the results of these three questions about evolution and human origins:

• Across the three question wordings, the data show consistently that about half of Americans agree with the theory of evolution, believe that the theory of evolution is probably or definitely true, or believe that humans developed over million of years with or without God's guidance.

• Belief in the idea that humans were created pretty much as is 10,000 years ago is somewhat more dependent on the way in which this concept is measured. A little more than 4 out of 10 Americans -- when presented with three alternatives -- say they believe that God created humans in their present form 10,000 years ago. At the same time, two-thirds of Americans in a stand-alone question say they believe in the theory of "creationism" -- defined as the idea that humans were created in their present form 10,000 years ago.

It might seem contradictory to believe that humans were created in their present form at one time within the past 10,000 years and at the same time believe that humans developed over millions of years from less advanced forms of life. But, based on an analysis of the two side-by-side questions asked this month about evolution and creationism, it appears that a substantial number of Americans hold these conflicting views.

These results show that:

• 24% of Americans believe that both the theory of evolution and the theory of creationism are probably or definitely true
• 41% believe that creationism is true, and that evolution is false
• 28% believe that evolution is true, but that creationism is false
• 3% either believe that both are false or have no opinion about at least one of the theories

Without further research, it's not possible to determine the exact thinking process of those who agreed that both the theory of evolution and creationism are true. It may be, however, that some respondents were seeking a way to express their views that evolution may have been initiated by or guided by God, and told the interviewer that they agreed with both evolution and creationism in an effort to express this more complex attitude.

Importance of Religion

It is important to remember that all three questions in this analysis included wording that explicitly focused the respondents on the origin of human beings.

This wording may have made Americans think about the implications of the theory of evolution in terms of humans being special creatures as reflected in religious teachings and in particular in the Judeo-Christian story of human origins as related in the book of Genesis. USA Today recently quoted Christian conservative and former presidential candidate Gary Bauer as saying: "Most of us don't think that we're just apes with trousers."

Thus, it is not surprising to find that many of those who do not believe in the theory of evolution justify that belief with explicitly religious explanations:

(Asked of those who do not believe in evolution) What is the most important reason why you would say you do not believe in evolution? [OPEN-ENDED]