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Psychologists Discover Their Own Biases

Evolution News

What persuades someone to accept one theory over another? People involved in marketing have been trying to tap into the roots of persuasion for years, but this question is rarely asked about scientific theories. The impression is that scientific theories are evaluated objectively by following the evidence where it leads. But what if two different people think the evidence leads to two different theories? The authors of this study published in PLOS One and recently reported in Science Daily set out to see if people prefer intelligent design despite “the large body of scientific evidence supporting evolutionary theory” because it is existentially satisfying.
The authors make several assumptions about intelligent design and evolutionary theory that have been contested in prior posts in Evolution News and Views. See below for a list of links arguing against the same assertions made in the introduction of this article. It is not the priority of this post to address these particular issues, but to look at the study itself and its conclusions.
The aim of this research is to determine whether the widespread acceptance of intelligent design theory over evolutionary theory is due to a psychological need to find meaning and purpose:

In the present research, we examined whether implicit concerns stemming from individuals’ awareness of their own mortality might be a cause of the widespread support for IDT and corresponding skepticism of ET seen among a wide range of individuals in North America. We tested the hypothesis that heightened mortality awareness would lead individuals to embrace IDT and reject ET; in other words, that shifting one’s opinion on these theories is a “terror management” strategy–stimulated by the basic need to maintain psychological security.

Based on the introduction to the article, the authors are assuming that there must be a psychological factor contributing to the support of intelligent design because if one were to base their views on evidence alone, then evolutionary theory would win. However, Evolution, News and Views often reports on scientific studies that either cannot be explained from evolutionary theory alone (e.g. development and genetics, metamorphosis) or are results that are counter-intuitive given the premises of evolutionary theory (e.g. junk DNA). Of course, as a psychologist looking for psychological reasons for intelligent design’s gaining popularity, the authors found that psychological factors are important influences for the acceptance or rejection of any scientific theory that has implications for one’s worldview. And as this study showed, evolutionary theory is no exception.
The authors refer to a psychological theory known as terror management theory. One aspect of terror management theory is that people tend to invoke psychological mechanisms to inhibit or distract from death-related thoughts. As the researchers point out, “These include enthusiastic adherence to meaningful conceptions of reality.” Their hypothesis is that evolutionary theory does not provide a meaningful conception of reality while intelligent design does, so when confronted with thoughts of death, people will prefer intelligent design theory over evolutionary theory. The authors designed an experiment to test this hypothesis. Overall, their experiment seemed to account for several variables and possible discrepancies, for example, the order in which passages were read by the participants was randomized to ensure non-bias. Statistical data and error were accounted for. In all groups, the researchers also tested whether effects were due to Christianity or other religious beliefs. Given these factors, there is still quite a bit of subjectivity and difficulty establishing causal effects, which the authors report in their discussion.
The Study:
Five different groups were studied. Each group was asked to think and write about their death in order to induce what the authors call a “mortality salience” or awareness of one’s own death. They were asked to write about death and then read passages by Michael Behe (intelligent design) and Richard Dawkins (evolutionary theory). Both passages discuss evidence for their respective theories and are non-religious in nature.* The students were then asked to rate particular items from the passage. Some groups were also asked to answer the question “How do you rate your religiosity on a scale of 1 to 10?”
Group 1: Psychology undergraduate students at largely liberal universities
Group 2: A diverse sample of students from across North America who did the same procedure above
Group 3: A diverse sample of adult Americans representing a wide range of socioeconomic and educational backgrounds who did the same procedure above
Group 4: Psychology students, half of whom were additionally asked to read a passage by Carl Sagan discussing how one can find existential meaning and purpose from a naturalistic perspective
Additionally, the survey followed up with this group four-to-six months later to account for bias. The authors wished to test whether positive responses for evolutionary theory increased with additional literature that discusses meaning and purpose from a naturalistic worldview.
Group 5: University-level students in natural science that were specifically selected because they, presumably, find meaning and purpose in a naturalistic worldview as this is the predominant worldview in their life’s work
In sum, each study had a control group. Each group was first asked to write and think about their death. Then the members of the group were asked to read passages in support of Evolutionary Theory (Dawkins) and passages in support of Intelligent Design Theory (Behe). Then they were asked to rate the passages. Group four was asked to read an additional passage that describes finding meaning in a naturalistic worldview then to rate the passages.
The Results:
Overall, the authors found that reminders of mortality promote relative support for intelligent design theory and skepticism towards evolutionary theory. While religion did correlate with initial ratings of evolutionary theory and intelligent design, there was no correspondence between religious beliefs and response to the passages after mortality salience. The results seem to be reversed by making evolutionary theory more meaningful.
Study 1 – Psychology undergraduate students from Liberal programs: Overall this study showed that there was no change in positive or negative views of evolutionary theory (ET) from before the mortality salience to after, however, it did show that there was an increase in positive response to intelligent design theory (IDT) after mortality salience. Other tests in this study showed that religion affected the initial rating of ET and IDT, but did not affect the rating after mortality salience, therefore the increase in positive view of IDT was independent of religious background.
Study 2 – Various university students in North America: This study had similar findings to Study 1, but after mortality salience there was not only an increase in positive views of IDT but also an increase in negative views of ET. Study 1 did not show an increase in negative views of ET. The authors assume this is because evolutionary theory is an important part of the field of psychology specifically, while Study 2 has a greater diversity of university students.
Study 3 – Various adult Americans: The results for Study 3 are very similar to Study 2 in that after mortality salience there was an increase in positive views of IDT and an increase in negative views of ET. In this case the sample is of various educational levels. The implications of both Study 2 and Study 3 are that in view of their death, participants preferred a theory that provides meaning and purpose:

Despite the superficial differences between these responses, at an underlying conceptual level they are coherent; participants respond to existential concerns by increasing their relative preference for an apparently “scientific” theory (i.e., IDT) that can provide a sense of meaning and purpose to the human endeavor, and/or decreasing their support for the theory that fails to do so.

Study 4 – Psychology students, half of whom read an additional passage by Carl Sagan: The results of this study showed that after reading the Sagan passage which discusses meaning and purpose in naturalism, students showed less of a positive response to IDT as compared to the control and sometimes showed antagonism or negative responses to IDT. These students showed a more positive response to ET as compared to the control. This indicates that purpose and meaning play a significant role in the preference for a particular theory.
The authors believe that the Sagan passage provided the meaning and purpose that the students wanted. However, the finding that they became increasingly antagonistic towards intelligent design also seems to indicate that intelligent design was threatening their source of existential comfort.

Specifically, the finding that reading Sagan’s excerpt moderated the interaction between MS and attitudes toward ET versus IDT suggests that a desire to see human life as having greater meaning and purpose likely underlies our previous effects. Reading the Sagan passage apparently dissuaded participants from embracing IDT as a way of managing existential concerns, and in fact made participants facing existential threat more antagonistic toward IDT, presumably because it threatened the theory that is the true mainstay of their scientific worldview and that could now be seen as providing existential meaning. This result is important because it addresses the process underlying the causal link between MS and scientific beliefs.

Study 5 – University students in the natural sciences: In this study, natural science students tended to have greater negativity towards the IDT passage and a greater positive response to the ET passage after mortality salience. This is the opposite effect as compared to studies 1-4. The authors interpret the results of Study 4 and 5 as follows:

Together, Studies 4 and 5 thus suggest that individuals who can find greater meaning in a naturalist perspective respond to existential threat by rejecting IDT and trending toward greater belief in ET. Presumably, shifting these views in response to [mortality salience] allows these students to enhance symbolic immortality by reaffirming the scientific perspective that is a major part of their worldview and provides meaning and purpose.

While the authors were initially investigating reasons for a supposedly irrational acceptance of intelligent design, their results seem to indicate why some individuals, particularly in the natural sciences, will not even allow intelligent design theory as a viable contender in the market place of ideas. Free inquiry and exploration of ideas have been the touted hallmarks of liberal education; yet intelligent design theory is often banned from even being entertained as a viable contender for an explanation of certain observations. This study, while not necessarily providing a direct causal link, does suggest that those scientists who object to intelligent design are doing so out of a personal interest in protecting their worldview.
Another point of interest in this study: Even those participants who would most likely strongly hold to evolutionary theory because it is foundational to their discipline, such as the psychology students in Study 1, were more sympathetic to intelligent design in light of their mortality. They did not necessarily become more antagonistic towards evolutionary theory, but they were more sympathetic towards intelligent design. The authors offer a striking explanation for the results of this study in light of the results of Study 4:

Study 1 and 4 participants were largely middle-to-upper class and well versed (if not firmly entrenched) in ET and the scientific cultural worldview. These individuals appeared to be largely unmovable in their views of ET, probably because the theory has become such a mainstay in their worldview as social science students that, even if they would like to reject it when confronted with existential threats, this desire is negated by a compulsion to affirm ET as an important worldview component. Instead, these individuals modified their more malleable attitudes – those related to IDT, a theory with which they are almost certainly less familiar. (emphasis mine)

The question is: How strong is this compulsion to affirm evolutionary theory as an important worldview component? To put another way, is the compulsion to affirm evolutionary theory for certain individuals so strong that even in the face of conflicting evidence, even if they would like to reject it, they will not? This is turning the tables on the study, because the authors were looking for reasons why one would affirm intelligent design given what they perceive to be overwhelming scientific evidence for evolutionary theory. However, there is also quite a bit of data that cannot be explained by evolutionary theory and is evidence for intelligent design (See below). As the authors state in their conclusions, perhaps objections to certain theories have to do with psychological insecurity:

In addition to providing a psychological explanation for the popularity of IDT and antipathy toward ET, the present findings challenge the conventional assumption that attitudes toward such scientifically framed theories are determined solely by factors such as logic, educational background, and ideology, though previous research suggests that such factors clearly play a role [ref removed]. This is consistent with other recent studies on the motivational underpinnings of social cognition, which have shown that core insecurities regularly influence overt attitudes about ostensibly unrelated sociopolitical issues, and that such beliefs are thus often not objective, rationally derived constructions, but, rather, influenced by fundamental motivations such as the need to protect the self against psychological insecurity…The present research builds on and extends these previous findings by showing that such processes generalize to attitudes and beliefs in the scientific domain.

The authors go too far in assuming that psychological reasons are the only factor contributing to the popularity of intelligent design. This is a flawed assumption because two of their initial premises are flawed. They assume that there is no empirical reason to accept intelligent design (See several of the articles reported here including this article on a positive case for intelligent design, and they seem to imply that there are no empirical reasons to reject evolutionary theory (See several of the articles reported here including Bio-complexity’s most recent articles). However, their honestly in the implications of their findings is notable. Indeed, even scientists and even those scientists who affirm evolutionary theory, are influenced to affirm and reject theories by their worldview commitments. When Phillip Johnson wrote Darwin on Trial and Reason in the Balance, he was addressing these very worldview commitments. Thomas Kuhn alludes to this in various sections in The Structure of Scientific Revolutions. Every scientist has a worldview commitment to certain philosophical assumptions that are beyond the realm of empirical science. As this study shows these commitments are apparently very strong (upheld in light of one’s death) and are apparently strong enough that presumably even if one wanted to reject them, one does not.
Responses: “Anti-evolutionists need closure”
Discover Magazine blogger Christ Mooney responds to this study here. His blog post makes no mention of how worldview commitments go both ways or that finding meaning in naturalism or evolutionary theory also helps assuage death anxiety. What is most interesting about his post is that he mentions another study which says that anti-evolutionists (as he calls them) are more likely to need closure than evolutionists and concludes that these studies show that “anti-evolutionists” are “likely to be religious, need closure, and sensitive to fear and existential threat.” This seems to disregard the findings of the study reported here which actually shows that all groups seem to need meaning and purpose to assuage death anxiety.
From Mooney’s blog post:

Need for closure is particularly interesting-this is about craving certain and fixed answers and being uncomfortable with ambiguity and uncertainty, no matter the issue. It is no big leap to see how anti-evolutionist religious beliefs provide certainty. Anti-evolutionists who have achieved “closure” are thus probably very fixed in their views and highly dismissive of threats to them.

But according to the death anxiety studies, particularly Study 4 and Study 5, evolutionists responded to a need for meaning and purpose. Therefore, it is not just “anti-evolutionists” that need “fixed answers” and are “uncomfortable with ambiguity and uncertainty.” Apparently, anyone, when considering his own death, needs a type of closure or at least a sense of meaning and purpose.
Lastly, Mooney points out how “fixed in their views” the “anti-evolutionists” are. However, the study reported here showed that before mortality salience, everyone had a pre-conceived notion of evolutionary theory and intelligent design theory. Everyone in the study responded to mortality salience, meaning that no one was fixed per se because the strength of their support (and antagonism) for a particular view increased (or decreased). If any groups could be considered “fixed” it might be those who find meaning and purpose in a particular theory. Study 5 showed that the natural scientists already had a strong positive view towards evolutionary theory that increased after mortality salience. They also grew more antagonistic towards intelligent design theory. Study 4 showed that those who had read the Sagan passage had a similar response. Study 2 and Study 3 showed there was an increase in positive responses to intelligent design theory, and in some cases increase in antagonism in evolutionary theory.
Psychology studies such as this study tend to have a lot of variables because the subjects (human beings) are very complex. So caution is needed in how far one should take the conclusions of such a study as well as how much data one chooses to accept and reject. Mooney’s blog post seems to ignore the findings that worldview commitments affect everyone’s decisions, “anti-evolutionist” and evolutionist alike, and while he may want the study to be related to religion, the authors of the study reported here said that religion did not seem to play a role in mitigating the response to mortality salience.
*As David Klinghoffer notes in his post on this study, apparently the Behe passage was not completely written by Dr. Behe. See here for his discussion.
Introductory assumptions:
“Despite overwhelming evidence for Darwin’s theory of evolution (ET) and scientific consensus that intelligent design theory (IDT) is inherently unscientific…” Reference: American Association for the Advancement of Science (2006) Statement on the teaching of evolution. Available: Accessed 2008 Dec 16.
See here for ENV’s take on the AAAS.
“Although a Dover, PA, court ruled in 2005 that schools could not include IDT in Pennsylvania science curricula, the debate is far from over.”
For an overview of the Dover case, see here and here. Also the book Traipsing into Evolution evaluates the Dover case. See here and here for articles about Judge Jones as an activist judge.
“Many schools include IDT in science curricula; 25% of U.S. high-school biology teachers devote at least some class time to the topic, and nearly half of those view IDT as a “valid scientific alternative to Darwinian explanations for the origin of species”” Reference: Berkman MB, Pacheco JS, Plutzer E (2008) Evolution and Creationism in America’s Classrooms: A National Portrait. PLoS Biology 6: e124.
ENV reports on a more recent survey done by the same group.
“In 2008, Louisiana passed a bill permitting science teachers to use outside sources–including those supporting IDT–in curricula, and in 2009 the Texas state education board voted to allow IDT to be taught alongside ET in science classes.” Actually, Texas ruled that students are to analyze and evaluate evidence for and against evolutionary theory. There is no mention of intelligent design theory. See here for a press release.
The Louisiana bill encourages critical thinking on evolution and other scientific topics. It does not specifically mention intelligent design. See here for a press release.