Evidence for beliefs: What matters, and what doesn't

i-bffcfdfc2faa20c96b0189328ce7ec0c-spaghetti.jpgThe Flying Spaghetti Monster (source: verganza.org) is a satirical retort to advocates of "intelligent design," created as a joke to mock the belief that some "intelligent designer" created life. While the Flying Spaghetti Monster is funny, no one takes it seriously. Meanwhile, belief in a Christian God is stronger than ever, and advocates of the theory of evolution are unshaking in their support.

So what's the difference? Why do people hold some beliefs strongly, but readily discard others? Jesse Preston and Nicholas Epley have designed a technique to examine the types of evidence people are more likely to accept in support of their beliefs. They asked Boston commuters to fill out a survey in a train station. One group read a statement summarizing research on personal relationships:

Psychologists have argued that, whether choosing friends or falling in love, we are most attracted to people whose traits are similar to our own. There seems to be wisdom in the old saying "Birds of a feather flock together."

The second group read a similar statement about the relationship between self-esteem and aggression:

Although intuition suggests that people who are depressed or low in self-esteem are more likely to be violent or aggressive towards others, some research demonstrates exactly the opposite. In fact, people who are high in self-esteem are more likely to be aggressive toward other people.

These two findings were chosen because, though they are familiar to psychologists, they would probably be surprising to average individuals -- so any manipulation of these beliefs was likely to be unrelated to previously held beliefs. Next the commuters were asked to write down one of two types of evidence that might support the statement they had just read. They either wrote down "implications or observations that this research finding would explain," or reasons "why this finding would come about." Then each group was asked how important, meaningful, and relevant the findings were for them. Here are the results:

i-af9d07dae3a47c8b8b4ef660e0753dc2-belief2.gif

When people wrote about the implications of the research -- how it could be applied to the real world, they believed it was significantly more valuable than when they tried to explain why the research might be true. So without offering any evidence on the research at all, Preston and Epley were able to affect how people felt about the research: applications matter much more to people than explanations.

But what about religious beliefs? Aren't these beliefs so strongly held that no amount of manipulation by researchers can change them? Preston and Epley conducted a modified version of this same experiment with Harvard students who professed a belief in God (atheists in the survey group were administered a similar questionnaire, but their results were discarded). As before, participants were asked to write down either explanations ("observations that can explain God's behavior") or applications ("observations that God can explain"). Half the participants wrote down three items, and half were told to write down ten (though many were unable to come up with this number of examples). As before, they were also asked to rate the value of their belief in God on a 0-10 scale. Here are the results:

i-c2f65bb37ee8af370ba3e36ffb332611-belief.gif

Students who wrote down applications of belief in God perceived the value of that belief to be significantly higher than those who wrote explanations, and students who wrote more applications rated the value of their belief as significantly higher than those who wrote fewer applications.

It should be noted that the manipulations in these experiments did not impact the perceived truth of beliefs, only the value of those beliefs. In the first experiment, studying belief in psychology research, about 50 to 60 percent of respondents believed the research to be true, whether they were in the explanations or applications group. None of the respondents to the religious survey changed their belief in God. Nonetheless, the fact that the perceived value of even religious beliefs can be so readily manipulated in such a brief experiment is quite astonishing.

Evolution scientists may want to take note of these findings as they attempt to inform the public of the value of their research: people appear to value applications over explanations -- so instead of explaining the mechanism of evolution, a better tact appears to be to emphasize the applications. The fact that many useful vaccines have been developed based on the theory of evolution will impress more people than research showing how DNA can mutate and cause organisms to change.

And followers of the Flying Spaghetti Monster, if they want more adherents to value their ideas, would be well advised to show how his noodly appendages can touch all of us, in our daily lives.

Preston, J., & Epley, N. (2005). Explanations versus applications: The explanatory power of valuable beliefs. Psychological Science, 16(10), 826-832.

More like this

Originally posted on the old blog on 3/12/2006 My contribution to Darwin Day was pretty weak for a staunch supporter of science. Sure, I think the name is a bad idea, and want to rename it "Evolution Day," or at least something other than Darwin Day (I thought about maybe suggesting "Variation…
When the going gets tough, thousands of people try to boost their failing self-esteem by repeating positive statements to themselves. Encouraged by magazine columnists, self-help books and talk-show hosts, people prepare for challenges by chanting positive mantras like "I am a strong, powerful…
I've been hanging out with fellow atheists for a while now, and one of the more common discussions I've had when the topic of religion comes up is, why are people religious? The two most common answers I've heard from atheist friends and acquaintances are that religion is a fantasy designed to…
We've written a lot about video games and aggression here on CogDaily, and typically there has been heated discussion about the results. Why, commenters ask, aren't you talking about aggression in football players, or road rage, or in any of a thousand other situations? The most important reason is…

This is a brilliant post, I don't know why no one else commented on it. I think this research should really help explain to people like PZ Myers why people beleive in God. It's not that all theists are unbeleivably stupid, its just that they think differently. In fact they think more normally. Anyone student of philosophy knows the value of God concepts, often there is simply no way to formulate metaphysical arguments without God. I think most theists beleive in God because they find the concept to be incredibly useful. In that respect it is like our beleifs in secondary qualities like colors or smells; or moral constructs like "justice" "evil". None of these things exist in the scientific sense, but they are very useful to us in comprehending the world.

By James Gambrell (not verified) on 08 Feb 2006 #permalink

I like to think that when few people comment on a post, it's so manifestly brilliant that nothing needs to be added. That's just a belief on my part, but it applies well to my personal level of self-esteem ;)

I'm not trying to lower your self-esteem, but I would like to offer a comment on your conclusion:

"Evolution scientists may want to take note of these findings as they attempt to inform the public of the value of their research: people appear to value applications over explanations -- so instead of explaining the mechanism of evolution, a better tact appears to be to emphasize the applications. The fact that many useful vaccines have been developed based on the theory of evolution will impress more people than research showing how DNA can mutate and cause organisms to change."

I think that's a great thing to do and should be encouraged. However, we've already seen the creationist/ID response to playing up the role of evolution in explaing, for example, bacterial antibiotic resistance: "that's just microevolution! Macroevolution doesn't exist!" Unfortunately, showing the applications of evolutionary biology doesn't seem to help counter this canard.

Maybe the fact that we can test drugs and treatments on animals that enable us to make predictions about how humans will be affected is a good demonstration of the unity of life and common descent? Has this angle been emphasized?

Perhaps if we could actually clone dinosaurs with the help of frog DNA, a la Jurassic Park, evolution might be more convincing to the public? ;)

Excellent point, Big C. Clearly this one study isn't going to conclusively demonstrate all the best methods of persuasion, but it is an impressive demonstration of one method, which will probably need to be combined with other arguments in order for one side to prevail.