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The Debunking Handbook Part 3: The Overkill Backfire Effect

Posted on 20 November 2011 by John Cook

Update Oct. 14, 2020:
The Debunking Handbook is now available in an extensively updated version written by Stephan Lewandowsky, John Cook, Ulrich Ecker and 19 co-authors. Read about this new edition in this blog post: The Debunking Handbook 2020: Downloads and Translations

Excerpt 3 from this new edition of The Debunking Handbook explains the latest research about The elusive backfire effects.

The Debunking Handbook is an upcoming a freely available guide to debunking myths, by John Cook and Stephan Lewandowsky. Although there is a great deal of psychological research on misinformation, unfortunately there is no summary of the literature that offers practical guidelines on the most effective ways of reducing the influence of misinformation. This Handbook boils down the research into a short, simple summary, intended as a guide for communicators in all areas (not just climate) who encounter misinformation. The Handbook will be available as a free, downloadable PDF at the end of this 6-part blog series.

This post has been cross-posted at Shaping Tomorrow's World

One principle that science communicators often fail to follow is making their content easy to process. That means easy to read, easy to understand and succinct. Information that is easy to process is more likely to be accepted as true.1 Merely enhancing the colour contrast of a printed font so it is easier to read, for example, can increase people’s acceptance of the truth of a statement.2

Common wisdom is that the more counter-arguments you provide, the more successful you’ll be in debunking a myth. It turns out that the opposite can be true. When it comes to refuting misinformation, less can be more. Debunks that offered three arguments, for example, are more successful in reducing the influence of misinformation, compared to debunks that offered twelve arguments which ended up reinforcing the myth.1 

The Overkill Backfire Effect occurs because processing many arguments takes more effort than just considering a few. A simple myth is more cognitively attractive than an over-complicated correction.

The solution is to keep your content lean, mean and easy to read. Making your content easy to process means using every tool available. Use simple language, short sentences, subheadings and paragraphs. Avoid dramatic language and derogatory comments that alienate people. Stick to the facts. 

End on a strong and simple message that people will remember and tweet to their friends, such as “97 out of 100 climate scientists agree that humans are causing global warning”; or “Study shows that MMR vaccines are safe.” Use graphics wherever possible to illustrate your points.

Scientists have long followed the principles of the Information Deficit Model, which suggests that people hold erroneous views because they don’t have all the information. But too much information can backfire. Adhere instead to the KISS principle: Keep It Simple, Stupid!


  1. Schwarz, N., Sanna, L., Skurnik, I., & Yoon, C. (2007). Metacognitive experiences and the intricacies of setting people straight:Implications for debiasing and public information campaigns. Advances in Experimental Social Psychology, 39, 127-161.
  2. Reber, R., Schwarz, N. (1999). Effects of Perceptual Fluency on Judgments of Truth, Consciousness and Cognition, 8, 338-3426.

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Comments 1 to 20:

  1. Keep It Simple for the Stupid
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  2. "Don't confuse me with the facts, my mind is made up." Said by the Stupid
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  3. DrTsk#1 and funglestrumpet#2 I'm not generally regarded as stupid, but I am not a trained scientist. I spent my career as a successful computer analyst/programmer, indicating I have at least a logical and, I hope, open mind. I find simple information to be more easily digested than technical detail. For example, I would not know where to start in order to analyse satellite temperature records, but I do understand that the upper atmosphere is cooling because less heat is reaching it from the Earth's surface. It is not the pure science which informs me, it is the logical ideas extrapolated from the science. (I expect I could learn how to analyse the data, or even understand computer climate models, but I would still not be a scientist. In fact, I would be dangerous, as I might not notice if my results were wrong.) Of course, being unable to process the data myself, I rely upon those who can understand them to simplify their results for me in a reasonable, prudent manner. Being a cautious type, I like to see at least a second opinion and, preferably, a consensus. That is why I like following this site: I get to read many points of view and see plenty of discussion, so that I can come to my own decisions based on a weight of evidence. Moral: Keep it simple in order to inform the widest audience. You never know when your latest convert will become a leader of popular thinking.
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  4. Good point Doug. I read a few of the psychology papers associated with John and Steven's handbook and noticed trial lawyers and debaters are kings of simple explanations. They frame an explanation, give you the whole picture, in a simple manner using the key facts. Not that I'm suggesting we become more like lawyers.....
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  5. Does anyone else feel that the more organised deniers have already synthesised this information for their own nefarious and polar opposite ends of disseminating misinformation?
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  6. Doug#3. You seem like a reasonable person to me!! And you say you are not a scientist. Well you do have the capacity to become one, given your logical analysis and understanding that one should first question their own results over and over and over until fully satisfied of their truth. Why would you think I was referring to you?? Unless you are part of the minority group that spreads disinformation and false myths to manipulate the honest truth seeking people that try to make sense of the whole complex thing.
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  7. bit_pattern#5 May I suggest reading "Merchants of Doubt" by Oreskes and Conway, which has been recommended here in the past.
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  8. john, reading this makes me feel like an idiot. KISS indeed. i'm certainly going to change the way i communicate climate science because of this.
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  9. Look, Most scientists and Engineers are lousy teachers because they cannot connect easily with the public. That has always been a problem with all campaigns to inform the public. We need sites like this to help us find a common, simple to understand language. Who of us roll our eyes in disgust when we try to read a legal document (e.g. a contract). People can easily turn against something they do not understand (science). We are on to something here... Keep inquiring. Keep up the good work. - Peace and prosperity
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  10. This is a great series. I'm looking forward to the manual at the end of it. It's amazing how the internet allows for interaction and development of ideas among people that would never otherwise meet. The SkS team and website are a great example of that.
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  11. As part of my job, I help people prepare to lead or participate in public meetings or in press interviews. One of the things we talk about with them is "splenetics" -- in our definition these are people who, no matter what you say, will disagree and try to stop you or block you from having an honest debate or rally others to prevent consensus. We always demonstrate to them that how you deal with a "splenetic" person has a heavy influence on the fence-sitters or middle-of-the-road people. Ask a person to get out or have one of your staff pull them to a side bar and the crowd becomes suspicious and supportive of them. Absorb their wild opinions, personal insults or distorted facts while deflecting their hostility to you back to the facts of the situation, and eventually the group will police them up for you. (This is sort of what Mr. Gore was hinting at when he said to handle climate deniers as you would a racist person, by deflecting their hatred back to facts/reality/consensus, but that attempt to communicate backfired for him as it was sent through the media filter. Whoever advised him to inject racism into a talking point should be given office coffee pot duty for a year.) I don't know if this would help in the AGW communication efforts, but it is a great techique for group discussions or panels when someone attempts to wrench the works.
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  12. This has been helpful for me as a layperson - thankyou for the tips. I like the tips for handling the splenetic person, noble_serf. At uni we were taught that small group discussion is the teaching process employed if the learning involves attitudinal change ( eg we are individually responsible) . Also, I learn with information presented in visual form, auditory form, experientially and with time to reflect, to allow pennies to drop and dots to connect. I think in images and simplified, familiar concepts eg I see the pot of water steaming on the stove thinking about the ocean warming, water vapour and floods. I see the 2.5 Hiroshima bombs every second heating the ocean. I conceptualise my changing level of understanding as a result of following the information on this website in a visual metaphor : Instead of appreciating "I am in a moving vehicle", I now appreciate that " I am in a vehicle travelling too fast,accelerating and on the wrong side of the road heading towards a semi-trailer with my brakes about to fail" - where is the paper bag in case I hyperventilate !!! I'm interested in how to help other lay people in my life who are not locked into denial and haven't read much on the topic to learn enough about climate change in 10-15 minutes ( I'm trying to write a summary of most potent facts as a cover note attached to the Critical Decade Report to hand out to professional women at work with the explanation that this is what I've learned, would you mind reading this, have a think and let me know if it makes sense and suggest ways to improve my summary) But what are the minimum and most potent facts required to arrive at the level of understanding/connected dots of the metaphorical semi-trailer collision ? Another question: I attended a lecture recently in which the speaker mentioned path-dependence theory to explain why people and organisations sometimes don't change in the face of new facts. The theory went something to the effect of: 1) an individual or organisation's decisions will tend to be influenced by previous decisions and understandings (prior path)and 2) if reinforced by "group think" supporting those understandings and decisions will cause the individual or organisation to become "locked-in" and unable to change. Part of the cause of the problem is a refusal by the organisation or individual to accept that they/she/he could be wrong. Some of us joked after the lecture when politely challenging each others different views "you're not being a bit path-dependent are you ?". It gaves us language/concept to examine our own and each others professional views and how it is that an idea can attract a following and maintain the following long after it had been proven to be relatively of limited value. Though the lecture was on a different topic altogether (not climate change) I wondered if path-dependence theory is relevant to understanding "locked-in" resistance to change in individuals and organisations in regard to climate change facts and action or is it an unrelated issue? The lecturer gave the quote from John Maynard Keynes " When the facts change, I change my mind, what do you do?" but I don't think that would go down too well with those of a different view.
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  13. Sally@12 the quote from John Maynard Keynes " When the facts change, I change my mind, what do you do?" There is something that bothers me about the concept that "facts change", although perhaps that is the convention in economics ;-) (which my brother the Economist might take exception to...) Of course, when we accumulate more "facts", then "the facts" en masse will have changed. But we don't want to leave the impression that "facts" are malleable, because that makes "facts" just another opinion, which is not particularly scientific. I've made this distinction before on another thread, but we need to distinguish between Observation, Interpretation, and Conclusion. There are shades of gray in the boundaries, but it is worth trying to distinguish between these parts of the process of understanding. It is relatively easy to get people to agree on observations ("yes, that thermometer read 12.3C at noon today), but interpretations of a collection of observations become more speculative, and the conclusions we draw depend on those interpretations. The process that I try to follow is to collect all relevant observations (and accept that there can be errors in these), consider all reasonable interpretations of those observations, and draw conclusions that are supported by the evidence. They key ingredient is the willingness to consider additional observations and interpretations, and to change the conclusions when warranted, and that is the intepretation I would put on Keynes' quote. The catch is that different people will have different ideas of what is "relevant" and "reasonable". The bad part is when someone takes the view that observations and intepretations are only relevant and reasonable when they confirm the pre-conceived and inviolate conclusions that were brought to the table. That's not science.
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  14. Thanks Bob Loblaw. I like your distinctions between observation, interpretation and conclusions and how you go about it. Based on your tip, I will attach John Cook's "Guide" to my brief introduction to the topic because it wraps up observations, interpretation and conclusions better than I can. My ability to articulate in such a reasoned way just flies out the window sometimes especially if someone tells me it is all rubbish. I will try to apply the distinctions you have made in the way I write and speak about the issue. I am hoping I might get better with practise. I see what you mean about where that quote could lead and plus I think it would place the listener in a defensive frame of mind possibly resulting in them not listening at all.
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  15. DrTsk@1, 6 Your original comment was "Keep It Simple for the Stupid". My point is that most of the population are not scientists and, if intelligence distribution follows a Bell curve, most of the population is of average intelligence and not stupid. Thus, I was trying to show that we should keep things simple for the masses, in order to make our information accessible to and digestible by the greatest number of people. In my experience, we tend to gloss over the 'too hard' bits in information we process and only go back to try for a deeper understanding if the topic interests us, or if we need the knowledge for an exam . This has been an entertaining and informative thread of comments. I have certainly learned some useful tips.
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  16. Sally@14: You've prompted me to download the guide. I also bought a copy of "Climate Change Denial" when it came out, but still haven't had the time to read it. Now there are two things on the list. Doug@15: From a Devil's Advocate position, I'd be tempted to argue the elitist opinion that "average intelligence" and "stupid" aren't mutually exclusive, depending on your definition of "stupid". For practical purposes, though, "stupid" (or a more diplomatic term) should be reserved for the small minority at the low end of the distribution. I am reminded of a comment on a course evaluation back in my teaching days that said "the mid-term was so hard that half the class got below average". My thought was "the mid-term was so easy that half the class got above average!". A first-year class, where the student clearly hadn't taken (or understood) statistics, yet. Another throwback from my teaching days: the course outline for the first-year climatology course (half of one term) was very similar to the outline for the third-year climatology course (a full semester). The level of detail in the course was much different, though. Start with simple explanations and gloss over the details, but have a way of coming back to the details when a deeper understanding is needed. The difficulty in the "debunking" process is that the "skeptical" position is often based on either a strawman version of the simple explanation (which might require details to show why it is wrong) or an inflation of the uncertainties in the details (thus trying to make it look as if climatologists know nothing). For that reason, the SkS Basic, Intermediate, and Advanced tabs are a great idea. Sometimes, however, complex subjects just require complex explanations.
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  17. (-Snip-)
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    Moderator Response:

    [DB] Off-topic snipped.  Was warned about being OT here.

  18. TruthAtLast @17: That's precisely why a proper understanding of climate-change requires the complex interaction between solar winds deflecting cosmic rays, and how the Earth's magnetic field can divert sunspot-plasma, but not the higher-speed cosmic radiation from supernovas. ...and sometimes Occam's Razor is required. Flights of fancy and highly speculative fairy-tales with no evidence to support them are completely different from "explanations". I suggest that you read the last two sentences in my comment #13.
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  19. TatL#17: "creates a "rock-paper-scissors" scenario-- and that presents a wild-goose chase ... In turn, complex relationships evade such thinking, creating a "blind man touching an elephant" scenario," Wow. Three hoary old chestnuts at one go. Well done, sir; you've exemplified the statement in this post: A simple myth is more cognitively attractive than an over-complicated explanation. Some simple explanations, then: a. Science is not 'rock-paper-scissors.' Any time spent reading the complicated literature of climate science will demonstrate that. b. There are no wild geese to chase here. There is a clear objective: understanding what is happening and why, using the best available scientific references. By contrast, the denial-world loves to put up whole flocks of wild geese; they are distractions from the real questions. To answer your specific, see 'It's cosmic rays.' c. The parable of blind men and the elephant doesn't apply. We're not blind; we recognize that observations from multiple disciplines must be reconciled. That provides the familiar 'multiple lines of evidence' so clearly in evidence on this website. I will see your three chestnuts and raise you one: A frog at the bottom of a well” is a common Chinese idiom, referring to a person with a limited outlook."
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  20. TruthatLast posted the cosmic ray nonsense before here and I suggested he/she take it to the appropriate thread. It would appear he/she has not read the article (or possibly is just posting without reading following ups). Given this is repeat behavior, perhaps moderators should delete TruthatLast comments till they appear in the appropriate thread with a willingness to discuss.
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    Moderator Response: [DB] Agreed.

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