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I am currently reading the book ‘The Worm at the Core: On the Role of Death in Life’. I have to say that I am a bit skeptical about many of the statements posed, and I’m trying to identify why that is, so I decided to dive into some of the articles they reference.

One of the things I encountered was a reference to a paper by Schimel et al. (2007): "Is Death Really the Worm at the Core? Converging Evidence That Worldview Threat Increases Death-Thought Accessibility." In Study 5, they state:

The results of Study 5 demonstrate, once again, that exposure to worldview-threatening information causes thoughts of death to become more accessible

They base this on an experiment in which they compare the DTA (death-thought accesibility) in three groups:

  • creationist/anti-creation, creationists who read anti-creation material (n=20, M=2.75)
  • evolutionist/anti-creation, evolutionists who read anti-creation material (n=20, M=1.95)
  • creationist/control, creationists who read neutral material (n=20, M=1.90)

I have trouble to see the validity of the conclusion based on the experiment. Might it not also just be the case that creationists in general think more about death? And that reading a passage about the theory of evolution (which is inherently about life and death), makes everyone, regardless of their point of view on evolution, think more about death? I think the problem with this experiment is that there is a group missing in the experiment; the evolutionist/control group. It might be very well possible that this group has a DTA of 0.95 and a low SD. If that were the case, reading the passage has increased the DTA of both the creationists and the evolutionists and thus nothing can be said about the effect of worldview-threatening information. All we would then conclude, is that reading about evolution increases DTA.

I am not a researcher myself, nor am I very familiar with social sciences. I hope someone with more experience in these fields could explain to me if my train of thought is correct, or if not, where the fallacy in this train of thought is.

I would also be interested to find references to articles that contain experiments that substantiate the statement cited above.

Solomon, S., Greenberg, J., & Pyszczynski, T. (2015). The worm at the core: On the role of death in life. Random House.
Schimel, J., Hayes, J., Williams, T., & Jahrig, J. (2007). Is death really the worm at the core? Converging evidence that worldview threat increases death-thought accessibility. Journal of personality and social psychology, 92(5), 789. (Free PDF)

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  • $\begingroup$ Consider the possibility that a creationist believes that they will not really die, but instead will go to heaven, as it says so in the bible. The theory of evolution contradicts the bible, implying that the bible might not be correct, which may mean that going to heaven might not be true either. So if they're not going to heaven, they might really die -- and that can be a terrifying thought. $\endgroup$ – Justas Jan 6 at 23:48
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    $\begingroup$ Hate to be a party-pooper but I think study 5 contains no reason to change your prior beliefs about DTA, despite stat significance. Six binary outcomes per person and 20 people per condition is not very many responses: in simulation, I reckon the design requires around a .2 or greater difference between prob-of-death-completion before you get near a .8 chance of detecting a true effect, and differences that large would make the observed diff in means unlikely. Low power exacerbates the suspicousness of 5 sig results in a row, already at .33 if power was .8, which it isn't. $\endgroup$ – steveLangsford Jan 11 at 16:47
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Interestingly, the authors appear to have been aware of your concern:

Given that the only difference between these groups involved a subject variable for which there could be preexisting differences in DTA, we included a third group of creationists who read a nonthreatening essay.

Since the evolutionist/anti-creation and creationist/control groups had very similar scores, there was seemingly no reason to suspect different baselines. However, I agree with you that adding this third group may not have been sufficient to eliminate the potential for preexisting differences in DTA.

Dispositional DTA:

The study of preexisting differences in DTA baselines is relatively recent, and is called dispositional DTA. This line of research is indeed showing significant variation in DTA between different groups in control conditions, variation in reaction to primes, and even variation in reaction to delay - see Mikulincer & Florian (2000) for examples of all 3. So in light of this, I would not take it for granted that evolutionists and creationists should necessarily have the same dispositions.

Curiously, a study by Friedman and Rholes (2009) found religious fundamentalism to be negatively correlated with dispositional DTA (ie, greater fundamentalism = reduced effects on DTA). Although fundamentalism is not the same measure as creationism, it does suggest that evolutionists may even have higher dispositional DTAs.

Ultimately however, a (not independent) partial replication of Study 5 is reported in Hayes (2011) Study 4, in which pro-evolution participants are subjected to an anti-evolution prime or the same control material used in Study 5, and the same DTA measure is used immediately thereafter. While not having the creationist contrast, this experiment measures the evolutionists/control baseline missing from Study 5, as well as the effect of anti-evolution material on evolutionists. I do note that the criteria for selecting participants was slightly different than Study 5, but not substantially different (n=93).

DTA was higher in the Threat condition (M = 2.26, SD = 0.98) than in the Control condition (M = 1.68, SD = 0.96).

The results seem to indicate that the authors' assumptions about evolutionists' preexisting DTA may be valid.

Implicit primes:

The alternative explanation that reading about evolution might raise DTA in all participants due to the nature of the topic does not fit well within the context of existing DTA research. Explicit primes increase DTA only after a delay or distraction. For the immediate effects on DTA found in Study 5, an implicit prime must be used - ie, one that does not directly elicit thoughts of death. This is presumably what Studies 1-4 establish. Also see Steinman & Updegraff (2015) for a comprehensive review on the effects of explicit vs implicit primes on the need for delay.

In that context, had Study 5 not included evolutionists at all, the data gathered would have still been sufficient to conclude that reading about evolution increases DTA in creationists, substantiating the statement cited in your question. The study's novel inclusion of a group with an opposing worldview adds some valuable information from which to consider additional conclusions. That said, it would not be prudent in any case to make strong conclusions from a single, small, poorly controlled, unreplicated experiment. In my view, this study has many flaws that I won't rant about here. All I will say is:

  1. Good on you for checking references, that is rare and commendable.
  2. Good on you for applying critical thinking and questioning conclusions.

Re further references, the DTA hypothesis Wikipedia article contains many references to literature both supporting the cited statement and questioning the evidence for it. Lots more on Google of course.

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  • $\begingroup$ Thanks a lot for your clear, extensive, and well-researched answer, very much appreciated! $\endgroup$ – Florian Jan 12 at 9:09

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