More about the Pew poll on evolution acceptance

January 7, 2014 • 1:30 am

NOTE BY JAC:  I still am baffled by the Pew’s finding that Republicans seem to have become more creationist between 2009 and 2013, for the Gallup Poll shows the 20% disparity already in 2008.  In that poll, the percentage of young-earth creationists was 60% among Republicans, 38% among Democrats, and 40% among Independents. The gap that Pew says is widening, then, appears in the Gallup data to have been that wide already five years ago.  Since the issue is the same, human evolution, I can only attribute it to different sampling techniques or, as Greg suggests below, to the order in which questions were asked.

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by Greg Mayer

I’ve already posted twice on the Pew poll on evolution acceptance, first to bring it to WEIT readers’ attention while noting the disparity between the Pew poll and Gallup’s results on the same issue, and then to note an erroneous criticism of the poll by Dan Kahan. I’d like to note three further developments.

The most interesting is a further report from Pew written by Cary Funk (if you look at nothing else mentioned here, look at this report), I’ll mention two other items first.

First, Charles Blow at the New York Times, in a piece entitled  “Indoctrinating Religious Warriors“, considers what the poll says about the political and religious landscape of America. He’s saddened by the fact that more Republicans now accept creationism than evolution:

In fact, this isn’t only sad; it’s embarrassing.

I don’t personally have a problem with religious faith, even in the extreme, as long as it doesn’t supersede science and it’s not used to impose outdated mores on others.

But as Blow well knows, the only religious extremists that make the news are precisely the ones who want their faith to supercede science and to impose their mores on the rest of society. He attributes its recrudescence to the strategy of the Republican party:

But I believe that something else is also at play here, something more cynical. I believe this is a natural result of a long-running ploy by Republican party leaders to play on the most base convictions of conservative voters in order to solidify their support. Convince people that they’re fighting a religious war for religious freedom, a war in which passion and devotion are one’s weapons against doubt and confusion, and you make loyal soldiers.

There has been anti-science propagandizing running unchecked on the right for years, from anti-gay-equality misinformation to climate change denials.

Second, Andrew Sullivan, in “Converting to Belief in Evolution“, has looked at the poll again, and points to Karl Giberson (whom Jerry also commented on) asking whether evangelical Christianity’s antagonism to science will push young people away from evangelical Christianity. Giberson found this prospect “alarming”, but evidently Andrew doesn’t. (As a gay Catholic who accepts at least theistic evolution, Andrew has longstanding political and theological differences with evangelicalism.)

Finally, Dan Kahan has accepted that his chief argument against the Pew poll—that its reported numbers must be incorrect—is wrong. He did so in response to a commenter on his site, who provided a hypothetical numerical example refuting Kahan’s assertion. I showed that Kahan was in error with a general argument about the statistics of sums, but a concrete counterexample is also a satisfying form of refutation. But most importantly, Pew, without mentioning Kahan, has released a detailed answer to the question that Kahan thought indicated numerical hanky-panky: “If the views of the overall public have remained steady, and there has been little change among people of other political affiliations, how does one account for the Republican numbers? Shouldn’t the marked drop in Republican believers cause a decline in the 60% of all adults who say humans have evolved over time?” The answer is of course ‘not necessarily, and, in fact, not in this case’.

Kudos to Kahan for accepting the invalidity of his mathematical argument, but, oddly, he continues unchanged in his animus toward the Pew poll and one of its striking findings (see the updates and a further post here). As I said, his reactions to the poll seem to be “merely expressions of his own prejudices”, and not terribly dependent on the actual poll results, since he continues to hold them although though his conclusions on the poll have been shown to be in error. The whole sequence of what he writes about the poll is a wonderful example of the type of reasoning which, in another context, Sam Wang of Princeton has called “motivated reasoning“.

The new Pew report (which, as I said, is the thing really worth looking at here), clearly answers Kahan’s doubts. Here’s their table nicely illustrating, neither generally nor hypothetically, that there’s nothing wrong with their numbers (note that the last column shows, as stated in my first post, that the overall result is a weighted sum that includes all political response classes):

Pew 2nd evolution 2013-1

But what was the cause of the shift in Republican opinion? It’s not obviously due to changes in the demographic, religious, or ideological profiles of the Republican party, as they changed little between the two surveys:

Pew 2nd evolution 2013-2

Pew 2nd evolution 2013-3 To my mind, the most interesting new nugget in this report is that the biggest shift of Republicans toward creationism has occurred among the least religious Republicans. From the report:

In fact, however, the surveys suggest that the change in views on evolution occurred especially among the less religious segments of the GOP. Among Republicans who attend worship services monthly or less often, the share who say humans have evolved over time is down 14 percentage points, from 71% in 2009 to 57% today. Among Republicans who attend services at least weekly the share who believe in evolution has gone from 36% in 2009 to 31% today, a difference that is not statistically significant.

This may support the suggestion of, among others, Zack Beauchamp and Paul Krugman that accepting creationism has become part of Republicans’ “team” or “tribal” identity: very religious Republicans were already mostly creationist for religious reasons, and now less religious Republicans are following for reasons of party solidarity. (Oddly, Kahan, who called Krugman’s response to the poll “absurd” and “devoid of reflection”, seems to agree with this as well.)

The new Pew report also considers the possibility of wording issues affecting the response. In this case, it was not the wording of the questions on evolution (which were unchanged), but the words of the preceding questions. The 2009 survey was full of questions on science, which may have “primed” respondents to give more ‘scientific’ answers, while in the 2013 survey the evolution questions were preceded by religious questions. I would not be surprised if such differences have an effect; such wording effects may account for some of the disparities between Pew and Gallup results on the same issues.

Pew Poll: American evolution-acceptance holds steady, partisan divide widens

January 1, 2014 • 5:22 am

UPDATE by JAC: Dan Kahan of the Cultural Cognition Project of Yale Law School has further analyzed this survey and finds some problems with it: some data are missing in both the summary and the full report, and this makes it impossible to determine whether the pro-creationist tendencies of Republicans reflects a shift in ideology or merely a transfer of creationist Democrats into the G.O.P. or a move of evolutionist Republicans into the Democratic Party. I haven’t had time to analyze this in full, but what disturbs me is the big disparity between the Pew and the Gallup Polls.  I don’t know which one gives the correct data about Americans, but one thing I’ve noticed is that Pew polls always give results more favorable to liberal religion than Gallup Polls. (In this case, Pew shows far less acceptance of both creationism and theistic evolution than does Gallup.) If Pew releases more data I’ll try to give an update.

h/t: Carl Zimmer, Matthew Cobb

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by Greg Mayer

The Pew Research Center and the Gallup Poll are two large American polling operations that periodically include questions about the acceptance of evolution in their polls of the American public. Jerry reported back in April on the results of the last Gallup Poll, and two days ago the Pew, as part of its “Religion & Public Life Project“, released its latest results (press release; exact questions with answers; report). The overall result is little different from their previous survey on this question in 2009, which was 31/61 for reject/accept evolution.

Pew evolution2013-1

As expected, religion had a large effect on evolution acceptance: white evangelical Protestants are decisively anti-evolution while white mainline Protestants even more decisively accept evolution; in fact, acceptance is slightly higher among the latter than among the “unaffiliated”. “Unaffiliated” people include the non-denominationally religious as well as the non-religious.

Pew evolution2013-2

Also among what must be considered expected results are the following, as summarized by Pew:

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.

The results by age bode well for the future (we may be able to say of creationism, “this too shall pass”), while the results by educational attainment suggest that education is not entirely powerless against superstition.  [JAC: An alternative explanation is that it is largely those who accept evolution that seek or are successful in higher education.]

As you can see in the table below, Pew actually asked two different questions, one about “humans and other living things”, the other about “animals and other living things”. Each version was asked of about half of the total sample (about 4000, so 2000 for each version). The results are largely the same, although evolution acceptance is slightly higher for the “animal” version. [JAC: As Greg notes the differences are small; still, in 4 of 4 age groups, acceptance of animal evolution is higher than of human evolution. That is almost significant using the sign test, showing that people are probably less likely to think that our species evolved than did other species. ]

This shows the effect of exact phrasing of survey questions on the results obtained (an effect highlighted in a New York Times article on a different subject from Monday: see the 3rd and 4th paragraphs).

Pew evolution2013-5

The Pew release highlights the divergence in views along political party lines:

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.

Pew evolution2013-4

Back in April, Jerry noted this partisan divide in the Gallup data. Gallup had Republicans favoring creationism by a 22 point spread (58% creationism to 36 % evolution), while Democrats favored evolution by a 10 point spread (51% evolution to 41% for creationism), and independents favored evolution by a 14 point spread (53% evolution to 39% for creationism). In the Pew data, the comparable figures are Republicans with a 5% spread for creationism, while Democrats favor evolution by a 40% spread and independents favor evolution by a 37% spread. There is thus a large divergence between the Pew and Gallup data, with Pew showing Democrats, Republicans, and independents all much more favorable to evolution than do the Gallup data. Why might this be so?

To get at this question, let’s first unpack the Gallup data. Like Pew, Gallup asked about “human” evolution, and thus this part of the poll does correspond to what half the Pew sample was asked (and whose responses are the ones given in the colored graphs above). Gallup, however, gave respondents three choices: humans developed over millions of years without God guiding the process, humans developed over millions of years with God guiding the process, or humans appeared just as they are within the last 10,000 years. We may roughly call these three possibilities naturalistic evolution, theistic evolution, and creationism. Gallup has asked this same question going back to 1982:

Gallup evolutionNaturalistic evolution (the lower line) varies from 9 to 16%, with some hint of an upward movement; theistic evolution (middle line) varies from 32 to 40%, with not much hint of a trend; and creationism (the upper line) varies from 40 to 46%, again without much evidence of a trend.

Even though Pew’s first question only had two choices, we can find comparable data to Gallup in the Pew poll by looking at one of their follow-up questions. Respondents who accepted evolution were asked by Pew if they thought evolution was due to naturalistic processes or guided by a supreme being. This divides the Pew respondents into three groups based on what they accept, just like in the Gallup poll: naturalistic evolution, theistic evolution, and creationist. The results are these:

(The religious breakdown in the original Pew table has been omitted, so that the overall result, which is comparable to the Gallup results, is emphasized.)
(The religious breakdown in the original Pew table has been omitted, so that the overall result, which is comparable to the Gallup results, is emphasized; the full table is given below.)

For those who were asked the “animals” version of the question, the theistic/naturalistic breakdown was 24/35, again slightly less religious than those asked the “human” form of the question. So for the most recent polls, Gallup (2012) and Pew (2013) give the following breakdown for the American public as a whole:

Naturalistic evolution:   Gallup  15% ; Pew 32%

Theistic evolution:   Gallup 32% ; Pew 24%

Creationism:   Gallup 46% ; Pew 32%

Even allowing for a what is perhaps a random uptick of creationism in the latest Gallup poll (see Gallup graph above), there is a striking difference between the results of the two polls.

There are a number of differences in the wording of the questions that might account for this. First, Pew suggested that one of the naturalistic processes might be natural selection. Perhaps hearing the name of a familiar evolutionary mechanism encouraged more people to choose this response, as opposed to the Gallup phrasing, in which the absence of God was emphasized, and no natural mechanisms were mentioned in the naturalistic evolution choice.

Second, the time frame of the Gallup question on human evolution was “within the last 10,000 years”, while Pew’s asked about “since the beginning of time”. At first, I thought the Gallup anti-evolution response was the more extreme choice: in April, Jerry equated it to young Earth creationism (YEC), which is indeed associated with the 10,000 year figure. However, the Gallup question asked only about humans, so a respondent who is generally accepting of evolution, but thought that something special happened fairly recently in human evolution (ensoulment?), might have selected this answer. Thus, someone who put a high premium on human uniqueness, but would otherwise be a theistic evolutionist, might have chosen what on the face of it appears to be a YEC response in the Gallup poll.

Also, the Pew phrasing, “Humans and other living things have existed in their present form since the beginning of time” may have been too strong for some varieties of creationists, who believe that a certain amount of change has occurred in some animals, and that humans have ‘degenerated’ since the fall of Adam in the Garden, leading some of them to not pick the ‘creationist’ response. However, the alternative response in the Pew poll explicitly uses the phrase “Humans…evolved”, which I think few creationists, of any stripe, would have chosen.

None of these suggestions about how the wording may have shifted the responses seems fully convincing to me, and in the end I’m not really sure why the responses diverge between the two polls.

And finally, let me leave you with the full table of responses by religion to Pew’s follow up question on evolutionary processes. I would point out here that the “unaffiliated” are by far the group most strongly favoring naturalistic evolution, even though white mainline Protestants are slightly more accepting of evolution overall.

Pew evolution2013-3

(For the latest Pew poll, the margin of error was about 3%.)

‘”Nones” on the rise’ in US

October 9, 2012 • 8:46 am

by Greg Mayer

A new study by the Pew Forum on Religion & Public Life reports that the proportion of Americans who do not belong to any particular religion has grown noticeably:

The number of Americans who do not identify with any religion continues to grow at a rapid pace. One-fifth of the U.S. public – and a third of adults under 30 – are religiously unaffiliated today, the highest percentages ever in Pew Research Center polling.

In the last five years alone, the unaffiliated have increased from just over 15% to just under 20% of all U.S. adults. Their ranks now include more than 13 million self-described atheists and agnostics (nearly 6% of the U.S. public), as well as nearly 33 million people who say they have no particular religious affiliation (14%).

This large and growing group of Americans is less religious than the public at large on many conventional measures, including frequency of attendance at religious services and the degree of importance they attach to religion in their lives.

Trend in religious affiliation over time. Data from the General Social Survey. (Figure by the Pew Center, but not from the Pew data, which is for a shorter period (2007-2012), but shows the same trend).

Most news media attention has focused on the fact that Protestants are no longer a majority (for example, at NPR), while mentioning the increase of the unaffiliated as a cause. The “none” are mostly theists of some sort; 68% profess a belief in God in the Pew survey.