Can the Overton Window be deliberately moved by espousing extremist views?

Question

The Overton Window is a political theory that 'describes a "window" in the range of public reactions to ideas in public discourse, in a spectrum of all possible options on a particular issue.'

When I have heard the Overton Window discussed it is usually in reference to a later concept:

Other formulations of the process created after Overton's death add the concept of moving the window, such as deliberately promoting ideas even less acceptable than the previous "outer fringe" ideas, with the intention of making the current fringe ideas acceptable by comparison.

       Wikipedia

To summarise the idea in my own words: You can persuade people to move their opinion slightly and to accept ideas that are current unpalatable, by publicly proposing extreme, over-the-top views, until the more moderate versions seem like a reasonable compromise.

Wikipedia didn't cite any peer-reviewed articles.

Is there any research to support or discredit the idea that publicly proposing unrealistically extreme views tends to move public opinion toward more moderate versions that are in the same political direction?

(I learnt while researching this question, that there is a novel by political commentator, Glenn Beck, by the same name. I haven't read this novel, and I am not attempting to address any of its contents.)

Update: I see a few people repeating the claim in the comments, but still no-one has provided any evidence.

There is at least one competing model: that fringe elements on one side of a political spectrum will pollute the pool for others. That is, that people will dismiss moderate views because the extremists are so fringe. We could provide anecdotes for both of these theories, but that isn't evidence.

Answer 1

It is a cognitive bias known as anchoring bias. In an extremely cited article (according to google it has over 20 thousand cites), cognitive scientists Tversky and Kahneman explain that:

In many situations, people make estimates by starting from an initial value that is adjusted to yield the final answer. The initial value, or starting point, may be suggested by the formulation of the problem, or it may be the result of a partial computation. In either case, adjustments are typically insufficient

and they furthermore propose the following example:

In a demonstration of the anchoring effect, subjects were asked to estimate various quantities, stated in percentages (for example, the percentage of African countries in the United Nations). For each quantity,a number between 0 and 100 was determined by spinning a wheel of fortune in the subjects' presence. The subjects were instructed to indicate first whether that number was higher or lower than the value of the quantity, and then to estimate the value of the quantity by moving upward or downward from the given number. Different groups were given different numbers for each quantity, and these arbitrary numbers had a marked effect on estimates. For example, the median estimates of the percentage of African countries in the United Nations were 25 and 45 for groups that received 10 and 65, respectively, as starting points. Payoffs for accuracy did not reduce the anchoring effect.

—Judgment under Uncertainty: Heuristics and Biases by Tversky, et al. Science 27 September 1974: 1124-1131. DOI:10.1126/science.185.4157.1124

It is widely used in marketing and advertisement.

For example it is forbidden by law to use this trick to advertise seasonal sales — for example, if a shop sells a pair of shoes for 50£ in January, it cannot expose a "70£ 50£" sign to make it appear as a bargain in February.

Answer 2

After viewing a debate about an issue, the distribution of audience opinions moves toward the middle of the two given sides. To the extent that the Overton Window is influenced by televised debates and that "publicly proposing" ideas is similar to starting those ideas as a side of a debate, I see this as evidence for it being similarly manipulable.

(Sadly, even just to find my original sources, I see why you put this question here; the search terms "audience", "debate" and "opinion" are as muddy as they come. The best I could do is http://www.overcomingbias.com/2009/04/why-refuse-to-debate.html If anyone has better search-fu than I do in this domain, I would celebrate the inclusion of additional citations.)

Answer 3

I read about a new study that appeared in Frontiers in Psychology yesterday that is relevant to this question. It is open access, fairly readable and short, so I encourage you to check it out yourself.

The authors let German students construct a 9/11 narrative using a card deck with story elements. When they included more extreme statements, the number of official statements used dropped. This might be seen as evidence for shifting the Overton window by using extreme statements.
The authors also make the case that this mechanism may have been at work during the debate about Sarrazin's book "Deutschland schafft sich ab" (basically a German version of the Bell curve debate I talked about in my other answer).

The paper also has some general relevance for skeptics.SE because it's about how conspiracy theories form in people's minds.

Abstract

Reptile prime ministers and flying Nazi saucers—extreme and sometimes off-wall conclusion are typical ingredients of conspiracy theories. While individual differences are a common research topic concerning conspiracy theories, the role of extreme statements in the process of acquiring and passing on conspiratorial stories has not been regarded in an experimental design so far. We identified six morphological components of conspiracy theories empirically. On the basis of these content categories a set of narrative elements for a 9/11 story was compiled. These elements varied systematically in terms of conspiratorial allegation, i.e., they contained official statements concerning the events of 9/11, statements alleging to a conspiracy limited in time and space as well as extreme statements indicating an all-encompassing cover-up. Using the method of narrative construction, 30 people were given a set of cards with these statements and asked to construct the course of events of 9/11 they deem most plausible. When extreme statements were present in the set, the resulting stories were more conspiratorial; the number of official statements included in the narrative dropped significantly, whereas the self-assessment of the story’s plausibility did not differ between conditions. This indicates that blatant statements in a pool of information foster the synthesis of conspiracy theories on an individual level. By relating these findings to one of Germany’s most successful (and controversial) non-fiction books, we refer to the real-world dangers of this effect.

Limitations

The study had a very small sample (30 in total). The study was vulnerable to expectancy effects from both researchers (scored card decks, knew condition) and students (they might have guessed the objective and helped along, manipulation was not subtle) and several outcomes were used, several of which could have been interpreted as supporting the hypothesis.

Thus, I wouldn't place too much trust in their findings until they're replicated in a much larger sample.

Answer 4

Maybe you'd like to read this, in a way it's a case study of what you're asking about. I think it counts a little more than an anecdote, because it's systematically done, but it's just one issue of course.

Block (1995) describes how the publication of "The Bell Curve" by Herrnstein and Murray in 1994 shifted debate, so suddenly they were discussing "the degree of blacks' genetic inferiority" when it comes to IQ, when before it wouldn't have been okay to assert any genetic inferiority at all.

What you consider as possible affects what you think is an extremist position. The critics of Herrnstein and Murray have tended to trip over this possibility. For example, in a New York Times op. ed. critique that describes The Bell Curve as "bogus" and "nothing but a racial epithet" (Herbert, 1994), Bob Herbert insists that "the overwhelming consensus of experts in the field is that environmental conditions account for most of the disparity when the test results of large groups are compared". In effect, he uses known environmental effects on IQ to argue for a low degree of genetic inferiority in blacks.

[...]

Again, we can see that what you take as possible affects what you take as actual. As with the passage from Herrnstein and Murray that I quoted earlier, agnosticism ends up as agnosticism about just how genetically inferior blacks are.