Global Warming: Man or Myth?

Scientists can also wear their citizen hats

Truth is in the Bias of the Beholder

with 13 comments

There are many of us out there banging away at the blogs and publishing Web sites with the logic that presenting factual information should sway skeptics toward the overwhelming scientific consensus that humans are causing most of the modern day global warming.  I even wrote a lengthy blog post filled with tips to become a better science communicator. Unfortunately, the people we are trying to reach may have bias that impedes their ability to consider all the relevant information and also their ability to use proper reasoning strategies.  (In January 2010, I posted How to Talk to a Conservative to try to inform those with political bias why climate change was important to address.)

So what does that mean for those of us involved in the climate change information campaign?  It means that we need to make efforts to understand what causes bias and then use proper strategies to remove that bias (known as debiasing).  Fortunately, and a hat tip to Hank Roberts for finding this paper, Schwartz, et al. (2007) describes the role of metacognitive experiences in judgment and decision making and also the effectiveness of various debiasing strategies and public information campaigns.

The paper contains 105 additional reference and appears to be cited often.  The paper is difficult to read because of psychological jargon but after several passes through, I believe the main take-home points are:

  1. Decades of research shows that bias causes human judgment to fall short of ideal.
  2. Debiasing strategies often fail because they assume that people base decisions on relative information and proper reasoning strategies.
  3. Rational choice does not depend on the scenario being “high stakes” vs. “low stakes”.
  4. Encouraging people to “consider the opposite view” often does not work and in many cases makes them have a more entrenched view.
  5. Most importantly: Debunking myths may actually reinforce them!  Presenting “just the facts” is usually a better strategy.

Accessibility Experiences:

Accessibility experiences refers to the ease or difficulty with which information can be recalled and thoughts can be generated.  Most people believe that we would consider something more plausible if we could bring many rather than fewer positive attributes to mind.  Unfortunately, the authors show that this is often not the case.  For example,

  • people believe that they use their bicycles more often when they think of fewer rather than more instances of riding.
  • people believe that they are more assertive when thinking of fewer rather than more instances of when they displayed assertive behavior.
  • people hold a more confident attitude when they generate fewer rather than many supporting arguments.

In addition, people are more confident in their judgments when the information is easy to bring to mind.

Bottom line: A debiasing strategy will only work when people can easily generate a few alternatives to their current understanding.  Therefore, drive your points home with fewer rather than greater examples.


Processing Fluency:

Processing fluency refers to the ease or difficulty with which new, external information can be processed.  High fluency is considered to be a positive experience for people and therefore, if it is easy to process new information (regardless of accuracy or relevance) then that new information is judged to be better information than that which was processed with less ease.

Bottom line: Make your information easy to process and it will be accepted as having more value.


Attenuation of Bias:

Most believe that any strategy that causes people to consider alternative information should alleviate bias.  However, alternatives will only do so if they come to mind easily.  If a person is asked to think of many alternatives to his viewpoint, it will only strengthen his bias.  Ironically, the harder a person tries to avoid bias by searching for alternative information, the harder they will find their task.  In the end that person will be more convinced that his initial judgment was accurate!

Bottom line: Make your alternative viewpoints fewer and more easily to come to mind.  In business this is called the “sticky factor”.  We all remember commercials such as “Where’s the Beef?” and the Energizer Bunny “Keeps going, and going, and going…”  See Made to Stick for ways to make your message more memorable.


Fluency, Familiarity, and Truth:

Familiar information is easier to process than new information.  The perceived familiarity of information increases the likelihood that the information is true.  When the truth is difficult to determine, people often resort to social consensus information to judge the truth – if many people believe something is true then there must be truth to it.  Repeated exposure to a statement increases the likelihood that it will be accepted as true.

Bottom line:  False information is better left alone!  Any attempt to discredit false information will essentially be repeating it which can lead to familiarity and acceptance of the false information.  Debunking false information is based on the assumption that people will base their judgments on the actual information at hand.  This strategy often fails because it does not consider the metacognitive experiences that shape people judgments.


Spreading Myths by Debunking Them:

The figure below is a flyer published by the Centers for Disease Control (CDC) that attempts to debunk myths regarding the flu vaccine.

CDC Flyer: Flu Vaccine Facts & Myths

CDC Flyer: Flu Vaccine Facts & Myths

It is clear that the facts strongly support getting a flu shot but because myths are repeated they may actually be reinforced.  A test was given to a group to see if the flyer was effective.

Right after reading the flyer people had a good memory of the facts vs. the myths and were mostly successful in identifying the truths vs. the myths.  Only 4% identified the myths as true and only 3% of the facts as false.  However, after 30 minutes, these same people identified 15% of the myths as true and 2% of the facts as false.  Once memory for details fades, familiar statements are more likely to be regarded as true and there is a higher rate of error when identifying false statements than true ones.

Bottom line: The attempt to debunk myths actually reinforces these myths after a delay of just 30 minutes.

When people were shown the CDC  flyer with just the facts, even after a delay of 30 minutes, they felt more positive about the vaccine and were more inclined to receive the vaccine.

More importantly, when people were shown the flyer with both facts and myths, they were less inclined to feel positive about the vaccine and were less inclined to get the vaccine than people who never saw the flyer!

After 30 minutes, the Facts & Myths flyer backfired.  It facilitated acceptance of myths as facts, impaired people’s attitudes toward vaccination, and undermined their intentions to receive the shot relative to those who never saw the flyer.

Bottom line: Providing just the facts had the intended effect on attitude and intention immediately following the information and after a delay.  However, after a short delay, debunking myths did not.


Lending Credibility to Myths:

Debunking myths may also have the unintended effect that the myth is eventually associated with a highly credible source.  An Internet rumor (urban legend) about flesh eating bananas became attributed to more and more credible sources including the CDC and the Los Angeles Times after these two organizations attempted to debunk the rumor.

In another study researchers exposed people to various “urban legend” statements such as “the wax to line Cup-o-Noodles causes cancer in rats.”  Participants were exposed to these statements either two or five times.  Next, these people were told that some statements were taken from the National Enquirer (low credibility source) and some from Consumer Reports (high credibility source).  A given statement was more likely to be attributed to Consumer Reports than to the National Enquirer the more often people were exposed to it.

Frequent exposure increased the acceptance of a statement as true and also caused people to believe the statement came from a highly credible source.  Furthermore, when a person attributes a statement from a highly credible source, he is much more likely to accept and to spread that information to others.

Bottom line: Countering false claims in ways that repeat them will cause them to be associated with highly credible sources which leads to greater dissemination of that false claim.  Just state the facts!

The next time you try to convince somebody that they may have false information, be sure to remember:

Truth is in the Bias of the Beholder


Written by Scott Mandia

May 24, 2010 at 7:36 pm

Posted in Uncategorized

13 Responses

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  1. You come across as quite significantly biased.

    Maybe you should spend some time in front of a mirror?


    May 25, 2010 at 11:45 am


    Thought you guys would enjoy seeing how you did in one of your rare debate appearances.
    Cheers Mates


    May 25, 2010 at 4:44 pm

    • Do you mean this Monckton?

      You will need a much more credible hero if you wish to get any respect around here.

      Scott Mandia

      May 25, 2010 at 6:06 pm

      • well if you think Monkton is so beneath you, since he’s trounced your side twice in the rare debates your side participates in, what does that say for your side?

        Mandia: Scientists are not good communicators but Monckton is. The winner of a debate is not the one who is correct – it is the one who most appears to be correct. Can you think of others who were excellent orators but were not correct? How about Adolph Hitler, Reverend Jim Jones, Osama bin Laden?

        And you just proved that you have a very strong bias.
        Before you snip my comments this is very much on topic since it goes to prove a very strong bias which is the topic at hand.

        Brad Blosser

        May 25, 2010 at 6:37 pm

    • Whether Monckton wins a debate at Oxford Student Union or a footbal match at Wembley stadium – it does not change the laws of physics.

      Science does not rely on public relations.

      dr schweinsgruber

      May 28, 2010 at 1:02 pm

      • Does this mean “The Consensus” is worthless? Does this undermine the existance of this and hundreds of other AWG blog?


        June 1, 2010 at 7:05 pm

  3. Let’s talk about some REAL truth here, shall we?

    Click to access monckton_what_hockey_stick.pdf

    And while you’re at it, why not discuss WHY it was that Michael Mann used a proxy –tree rings– in an attempt to determine temperatures when virtually every other scientists in that field of endeavor advised against it for the known reason that BOTH CO2 and good weather affect tree ring growth.

    In fact, EITHER will induce tree growth in the relative absence of the other.

    If what Monkton says in the above PDF is ~so terribly~ wrong, then WHY are YOU NOT taking him to court over the matter?

    Why not?

    Obviously if your case is so airtight, then you should have no problems, right?


    Mandia: We would not take Ronald McDonald to court if he made those statements so why should we take Monckton to court? Unlike the anti-science crowd, scientists are not in the business of suing people. We are in the business of solving important questions to help mankind.


    May 25, 2010 at 7:30 pm

    • This topic is not about hockey-sticks. Multiple reconstructions from multiple proxies yield similar results to those from tree rings. In fact, the Mann et al. (2008) reconstruction was essentially the same with or without tree ring data. You will need to view the supporting information to see the hockey stick with various proxies removed.

      Please stay on topic.

      Scott Mandia

      May 25, 2010 at 7:46 pm

  4. Scott, I note that the denialists on this thread have already taken the message to heart. To increase public acceptance of their notions, all they need do is repeat them at every opportunity.

    However circumstances make debunking a sad necessity. When public discussion takes place, as is inevitable on matters of public policy related to scientific findings such as global warming, we just have to accept that the audience will be exposed to myths and a fair minority of them will walk away believing those myths both by dint of repetition and because in confronting those myths we have, in the mind of many viewers, lent them credibility.

    This isn’t news to seasoned politicians. One basic rule of thumb followed by all politicians is that if you’re ahead you refuse offers of public debates and you avoid mentioning your opponent.

    Science is well ahead on this issue, though there will always be stumbling blocks. Full steam ahead, steer all discussion towards the facts, and ignore the nonsense and noise-makers.

    Tony Sidaway

    May 26, 2010 at 7:39 am

  5. One debunked myth that is still ghosting around is that spinach contains lots of iron. This is based on an error when the figure was written down and the comma placed incorrectly. Even French fries have more iron than spinach.

    dr schweinsgruber

    May 28, 2010 at 1:00 pm

  6. It appears that the story about the decimal point error for iron in spinach may itself be a rather complex, and rather old, myth.

    Tony Sidaway

    May 30, 2010 at 10:48 am

  7. Scott,

    Great points. But it hard to avoid debunking people like the oily Viscount. I hope John Abraham’s presentation and the Climate Crock videos have been circulated among those Oxford students!


    June 2, 2010 at 6:04 am

  8. Seems the good Viscount has allies, an insider to the IPCC and a well respected climate scientist….well respected until now, here.

    Click to access Hulme-Mahony-PiPG%5B1%5D.pdf


    June 14, 2010 at 3:57 pm

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