An Analogy

I can’t remember where I first read about this phenomenon. It could have been here, here, or somewhere else entirely.

Whoever it was wrote a brilliant post about the widespread public belief that “the truth lies somewhere between the two extremes”. This belief was a fallacy, the author argued, as one side could easily make themselves as extreme as possible – moving their end of the spectrum so that the centre moves closer to their original position.

“The warming is natural” sounds ridiculous until you compare it to “it hasn’t been warming at all.” Someone says that “CO2 accumulation is caused by volcanoes”, but then someone else claims “CO2 doesn’t even affect the global temperature.” Little by little, the centre – the position between the two extremes, which the public is most inclined to trust – shifts.

This phenomenon reminds me of a math problem from a few years back, which, for whatever reason, stuck in my mind. It had to do with different car companies, and what form of simple averaging – mean, median, or mode – was the most appropriate to honestly convey to customers the price of a typical car.

One company had cars with prices $25 000, $28 000, $23 000, $30 000, and $21 000. (No, I don’t remember the exact numbers. Yes, I am making them up.)

Another company had cars priced $35 000, $31 000, $38 000, $34 000, and $10 000.

See the analogy?

Make one end of the spectrum as extreme as possible, and the mean average – or public opinion – will shift accordingly.

In a public debate such as climate change,  I don’t think we should use the mean. We should use the median. That way, even if the same scientists become progressively more extreme in their views, the public’s interpretation of the credible opinion will stay relatively the same. It’ll only significantly change if that minority of scientists is able to convince the others of their views.


15 thoughts on “An Analogy

  1. An interesting analogy but one that ideally should have little relevance to the question of AGW.
    The reality or otherwise of Global Warming and more specifically man’s role in it, is not a matter of opinion much less one of head counting or marketing, rather it is a hypothesis that will ultimately be validated (or not) through the accretion of scientific observations, measurements and experimentation over time. As an unconvinced but concerned observer and a non-practicing scientist, I feel that the reason why the proponents of AGW are failing to carry some/many/most(?) of the public with them is less due to the tendency of people to position themselves at the perceived ‘centre ground’ between conflicting opinions but has more to do with the disjunction between the findings reported with careful qualification in the academic press and their presentation in the popular and quality press where every ‘may’, ‘possible’, ‘probable’, ‘could be’ etc is ignored in favour of ever more hysterical, unbelievable and observably unreal claims of imminent catastrophe. Such claims are so far removed from people’s everyday experience of ‘weather’ and their perceptions of ‘the climate’ that an intellectual dissonance is established frequently leading to rejection of the central argument.

    A further issue is the lack of respect shown by some advocates of AGW for those others (including climatologists, other scientists, journalists and members of the public sufficiently interested to have informed themselves about the issues) who are sceptical of some or all of the evidence and arguments being offered. These people are not followers of some Dark Lord engaged in a conspiracy to bring about apocalypse, rather they are simply unconvinced by the arguments offered, for reasons ranging from silly to serious.

    Finally, I’ve enjoyed your postings and admire your ambition to become involved in this critical debate as a professional climatologist .
    Bon chance,

  2. Unfortunately, calculated use of this tactic works because naked apes use heuristics, and one of the big ones is “anchoring”. Even the act of simply mentioning an outlier draws people’s attention and intuitively biases their assessments towards it… doesn’t seem fair, somehow, but that’s the playing field…

  3. The tactic often used is to put forward an extreme opinion to then let the listener accept a slightly less extreme version of it. In advertising the same tactic is used: From 799 now for only 499! (when in fact the product was never sold at 799 in the first place, and other stores sell the same product for typically 450 bucks). It works though, unless people do a little research or see through the tactics.

  4. I don’t think science should be based on consensus in this way, mean, median, or mode. Your numbers for the cars aren’t low enough. The lot with the 10K car still has the higher average.

  5. Scientists are not like the rest of us, they are so incredibly conservative in their public pronouncements. Great excitement in the field becomes an interesting development in statements to the press.

    So when the scientific community comes out and says that we are creating a very different future, they are very confident where I would say certain.

    So given the uncertainties in climate modelling it is easy to see that the problem will probably be worse than the public statements.

  6. TG:
    Oddly, compared to your comment, almost all the extreme claims I ever see — extreme as compared to the professional opinion — are made from quite a different quarter than you complain of. Claims like ‘global depression’, ‘hundreds of trillions of dollars cost with no effect’, ‘excuse for one world government and government dictating everything to you’. Pretty extreme, it seems to me.

    Back almost 20 years ago now, I was a regular in the Usenet newsgroup sci.environment. Sea level was one that came up routinely back then. Back then, there were equivalent ‘two sides’. On one side were those who claimed that the Antarctic ice sheet was going to melt tomorrow and drown the entire world (Waterworld movie scenario). On the other side were those who claimed that the Antarctic ice sheet couldn’t melt — at all — and that sea level couldn’t change — at all. While the ‘we’re all going to drown tomorrow’ folks have disappeared (at least in the sense that I don’t see them any more, and I do look from time to time), the ‘sea level can’t change’ folks are still at it, with the same arguments as they were using in 1990.

    For the ‘lack of respect’, well, that would be enormously better for a particular example. Name a climatologist whose opinion you prefer who has been shown a ‘lack of respect’, and give a researchable example of another scientist who was doing so. Does have to be two scientists involved. There’s an awful lot of garbage out there from the non-scientists, and I pay little attention to it regardless of what position the garbage advocates are pushing. I’m more concerned about what the professionals are up to.

    You might have a real point. You might just be misreading what is typical disagreement mode between scientists. And you might have zero examples that involve professionals, in which case — why worry about that? We’ll see after you post the example.

  7. At the same time, some people such as Al Gore are vastly overstating the effects of global warming. So it works both ways. Whichever direction it’s coming from, though, it is a fallacy. [I’d be interested to know what you thought he was overstating – read the post Why Al Gore Doesn’t Matter for my complaints. -Kate]

  8. O’Donnell, are you saying that it’s OK for climate inactivists to exaggerate their claims, because global warming theory proponents do it too?

    * * *


    To complicate matters, there’s also the phenomenon that when one person repeats the same opinion 3 times, it has almost as much impact on people’s perception of opinion as 3 people independently voicing the opinion. This means that not only does the PR game favours those who espouse extreme views, it also favours those who repeat their views incessantly (creating the false impression of a ‘chorus’).

    Climate inactivists are often both extreme and repetitive, and (at the risk of repeating myself) this is no accident.

    Using your analogy, it’ll be as if the 2nd company decided to put up lots of posters everywhere saying “WHY SHELL OUT $21,000 WHEN YOU CAN GET THIS CAR FOR $10,000?”, while sending out lots of people with megaphones blaring out the same message day in day out, posting about the other guy’s $21,000 car all over the blogs, and making robophone calls about the $21,000 car to Senators.


  9. I can go more extreme in both directions:

    Only 10 years to avoid a 25-metre rise in sea level from the 2007 “Australian of the Year” Professor Tim Flannery:

    I think he’s misquoting Hansen but he should still know better.

    Or, the Earth isn’t warming, its actually about to enter an ice age:

    I’m not sure you could prove which side of the debate is being more extreme, there are plenty of other examples out there.
    [Keep in mind that this is obviously a debate within the media that we’re talking about – does it actually give any bearing on what’s happening in the scientific community? Are there examples of one or both sides being too extreme in the scientific literature (which is really all I care about to get a sense of which side to trust)? The first IPCC report doesn’t count, because they made it very explicit that they didn’t include aerosols. -Kate]

  10. Mike N,

    On complex matters of fact, a consensus amongst experts is absolutely relevant. (

    “Scientific knowledge is the intellectual and social consensus of affiliated experts based on the weight of available empirical evidence, and evaluated according to accepted methodologies. If we feel that a policy question deserves to be informed by scientific knowledge, then we have no choice but to ask, what is the consensus of experts on this matter.” (Naomi Oreskes, via


    In addition to the points raised by Robert Grumbine, I think the effect of the language used by scientists is exactly opposite of what you claim. Scientists are used to speaking in terms of uncertainty, and always use weasel words such as ‘may’, ‘possible’, ‘probable’, ‘could be’. This gives many people the false impression that they just don’t have a clue, whereas in reality, it’s just a different lingo they use. Where the media goes wrong in twisting the scientific message is not so much in leaving out those weasel words (though they may), but in presenting two sides of the story as if they have similar scientific backing (which they obviously don’t).

  11. I’ve never (yet) been hard-working enough to do actual science. all the citations, background checks that need to be done and basically the need to consentrate on a subject for a long period that is essential for a good scientist are somewhat lacking. Add to that the making of science has somewhat changed due internet and by great many computer programs, that I’ve not got familiar with. For me, the short attention span is one obstacle to overcome when reading of science, maybe this is a wider phenomenon. F.e, I prefer to read only the abstract (and get frustrated if it doesn’t explain the objective of the study) and the results (and get frustrated if I have to read more to sort of ‘get it’).

  12. Robert Grumbine
    The points I was making are simple and I feel, self evident; I believe that scientists reporting evidence for AGW do their case few favours if in press releases or comments they focus on the most dramatic or doom laden implications of their research. [citation needed – “the media exaggerates the problem of climate change”. Go read some Boykoff and Boykoff, which is an appropriately peer-reviewed document. The media certainly can be too extreme, but to claim that they are only extreme in leaning to one side fails to capture the full range of journalistic screw-ups in our world. -Kate]

    My second point was not to accuse climatologists who support AGW of lack of respect for their peers (although some of the wilder utterances of Dr James Hanson are rather questionable in this context) but rather to suggest that it would be more productive for all proponents of AGW to treat those who are genuinely unconvinced with respect and civility. (Obviously, there are some/many who blog and write on the issue of AGW for whom the science, the interpretations and the arguments are irrelevant, who have no interest in anything other than what they perceive as the ‘politics’ of the issue or who clearly don’t give a damm about global warming whether anthropogenic, natural or LGM. Your point re. melting of the Antarctic ice sheet is wholly relevant as far as this group is concerned)

    However, I suggest that the great majority who visit sites such as BraveNewClimate, WWUT, RealClimate, Climate Audit, Climate Science etc etc are concerned, engaged and anxious to learn and span the full range of the convinced-sceptical spectrum.

    Both points made are particularly relevant to the less convinced element of this audience of the ‘intelligent unconvinced’. This I believe (as I’ve posted on RealClimate’s current thread) is the critical target group, and it will ultimately be convinced one way or the other. This audience is counted in the tens of millions and at the moment political leaders around the world, increasingly concerned at the gargantuan task they have undertaken in attempting to implement policies designed to mitigate AGW, need the enthusiastic commitment of this group if they are to achieve their goals.
    If this audience remains unconvinced or moves to a rejectionist position then the likelihood of successful, politically driven intervention in the democracies will become vanishingly small.


  13. This is a well-established concept in behavioral economics as well. If you give people three options of varying price, they are most likely to choose the middle-priced option. For example, if a restaurant patron is trying to choose between two wines, a $15 bottle and a $25 bottle, he may go for the cheaper one, since it’s relatively hard to decide in a vacuum how much each bottle is worth. But if you add a $40 bottle to the menu, suddenly the $25 bottle seems much cheaper, and the patron will choose that bottle – a more expensive option than he would have otherwise. This explains why many restaurants will include high-priced items on their menus that few people ever buy–to make other items seem cheaper by comparison.

    Here’s a similar phenomenon described in the Harvard Business Review:

    “In our world of information overload, every new choice is an effort — so companies need to give as much thought to the process of choice as to those choices and options themselves. For instance, Dan noticed that the Economist, at one time, showed three options for their potential subscribers: online-only for $59.00, print-only for $125.00, or online and print for $125.00. He designed an experiment, using his students, in which 84% chose the $125.00 for print and online, 0% chose print-only, and only 16% chose online-only. Any rational manager would say the $125.00 offer print-only offer was useless. But when Dan removed the $125.00 print-only offer, 68% of people bought the online product for $59.00 while only 32% shelled out for the $125.00 bundle! In other words, the higher-priced option was chosen less than half as often. By having the decoy of $125.00 for print-only, the customer could make an easy comparison to the other $125.00 offer in which they got online for “free.” Even something as simple as choosing a magazine has enough complexity in it that a decoy choice can radically change buyer behavior.”

    Climate change is one such example of information overload. If you don’t understand the issue, you’re likely going to default to whichever “side” of the science confirms your pre-existing views on the role of government. This is what’s called “cognitive bias.”

  14. Tgo’d, the ‘intelligent unconvinced’ you describe in fact are the “intelligent disengaged” and the “intelligent self-interested.” Once unbiased intelligence engages the rather deep, broad, and overall solid field of scientific literature (the dreaded “peer reviewed” field) on climate change, the unconvinced part does/should diminish. As to your “respect” point, how much respect do you imagine is owed to someone who dismisses the science without conducting a rigorous review of the science? If it doesn’t bother you that the anti-AGW commentators have a vanishingly small amount of peer-reviewed publication on the direct climate change topic or that much hype flows from obsolete and/or cherry-picked data, then I submit that you yourself are disengaged. When the “skeptics” engage the literature head-on and with rigor, then and only then do they deserve deference. Until then, the Kipling paraphrase about keeping one’s head when one hasn’t heard the news comes to mind. In drastically simplified examples, how much respect should attach to a movie review/er who hasn’t seen the movie being reviewed, or to a commentator claiming that financial regulation is unnecessary without investigating the state of actual affairs? The request really is simple, and justified: Engage the Science in the Literature!!

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