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| {{quote box|I am particularly fond of this example [the Linda problem] because I know that the [conjoint] statement is least probable, yet a little [[homunculus]] in my head continues to jump up and down, shouting at me—“but she can’t just be a bank teller; read the description.”|[[Stephen J. Gould]]<ref name="Gould (1988)">{{cite news|last=Gould|first=Stephen J.|title=The Streak of Streaks|url=http://www.nybooks.com/articles/archives/1988/aug/18/the-streak-of-streaks/?pagination=false|newspaper=The New York Review of Books|year=1988}}</ref>|width=25%|align=right}}
| | == 5Jj1OK Brazil 6s 0d72pVfI == |
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| The '''conjunction fallacy''' is a [[formal fallacy]] that occurs when it is assumed that specific conditions are more probable than a single general one.
| | Mine are at 31.5 volts. If you pull the pack below the cutoff voltage, it WILL damage the pack. A few weeks ago, a colleague sent me a link to an article in the Wall Street Journal. It described a "laboratory adept European entrepreneur" and his chief chemist, who were mining the scientific literature to find ideas for new designer drugs dubbed legal highs. <br><br>In other words, the command to contract the biceps provokes another command within the spine to prevent contraction of the triceps. In this way, these antagonist muscles are kept from resisting one another. There information that going to be there that can validate your story, validate the facts."Now, eight years since the accident and a killer plea, the family continues to live with what happened. Walker, who was sitting beside his sister that night, says losing his Erica has motivated him."I will always do everything for her, just knowing that she up there looking down on [http://greeleyhatworks.com/wp-content/news/ sport blue 6s] me saying: that my brother, look what he doing now, said [http://www.noworriespoolservice.net/images/sport-blue-6s.html jordan 6 sport blue] Walker. <br><br>Michael Brown rallies across the nationPhoto essay: Police and protesters in FergusonCardinals hold off Marlins, 5 2A fifth night of unrest in FergusonA fifth day of rallies and protests in FergusonPlayers to watch galleryDoctor John's Adult Boutique started as a lingerie outlet in 1987 and expanded into an adult novelties by request but then growing into selling club apparel and shoes. We pride ourselves in customer service and a very knowledgeable staff. <br><br>The next important milestone we completed this quarter was [http://greeleyhatworks.com/wp-content/news/ sport blue 6s] the announcement of the three months data from the pharm/tox primate study. This was the first time point in the 12 month study, and so we're not necessarily looking for efficacy data. I am a 78 year old woman who was diagnosed with PD in March and given a prescription for carbidopa/levodopa. A second opinion in June confirmed the diagnosis, but I am reluctant to start taking the meds. |
| | | 相关的主题文章: |
| The most often-cited example of this fallacy originated with [[Amos Tversky]] and [[Daniel Kahneman]]:<ref name="Tversky & Kahneman 1982">Tversky, A. and Kahneman, D. (1982) "Judgments of and by representativeness". In D. Kahneman, P. Slovic & A. Tversky (Eds.), ''Judgment under uncertainty: Heuristics and biases''. Cambridge, UK: Cambridge University Press.</ref><ref name="tk83" />
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| <blockquote><p>''Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.''</p>
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| <p>Which is more probable?</p> | | <li>[http://www.tcnweb.ne.jp/~sitamachi/yybbs/yybbs.cgi http://www.tcnweb.ne.jp/~sitamachi/yybbs/yybbs.cgi]</li> |
| # Linda is a bank teller.
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| # Linda is a bank teller and is active in the feminist movement.</blockquote>
| | <li>[http://en.wikiatex.com/User:Bidmerazie#GvWZ0x_Brazil_6s_UkyblYEf http://en.wikiatex.com/User:Bidmerazie#GvWZ0x_Brazil_6s_UkyblYEf]</li> |
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| The majority of those asked chose option 2. However the [[probability]] of two events occurring together (in "conjunction") is always less than or equal to the probability of either one occurring alone—formally, for two events ''A'' and ''B'' this inequality could be written as <math>\Pr(A \and B) \leq \Pr(A)</math>, and <math>\Pr(A \and B) \leq \Pr(B).</math>
| | <li>[http://www.zwzj.com/upload/forum.php?mod=viewthread&tid=29263 http://www.zwzj.com/upload/forum.php?mod=viewthread&tid=29263]</li> |
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| For example, even choosing a very low probability of Linda being a bank teller, say Pr(Linda is a bank teller) = 0.05 and a high probability that she would be a feminist, say Pr(Linda is a feminist) = 0.95, then, assuming [[statistical independence|independence]], Pr(Linda is a bank teller ''and'' Linda is a feminist) = 0.05 × 0.95 or 0.0475, lower than Pr(Linda is a bank teller).
| | </ul> |
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| Tversky and Kahneman argue that most people get this problem wrong because they use a [[heuristics in judgment and decision making|heuristic (an easily-calculated procedure)]] called [[representativeness heuristic|representativeness]] to make this kind of judgment: Option 2 seems more "representative" of Linda based on the description of her, even though it is clearly mathematically less likely.<ref name="tk83">{{Cite journal |author=Tversky, A. and Kahneman, D. |year=1983 |title=Extension versus intuitive reasoning: The conjunction fallacy in probability judgment |journal=[[Psychological Review]] |volume=90 |issue= 4 |month=October |pages=293–315 |url=http://content2.apa.org/journals/rev/90/4/293 |doi=10.1037/0033-295X.90.4.293}}</ref>
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| In other demonstrations they argued that a specific scenario seemed more likely because of representativeness, but each added detail would actually make the scenario less and less likely. In this way it could be similar to the [[misleading vividness]] or [[slippery slope]] fallacies. More recently Kahneman has argued that the conjunction fallacy is a type of [[extension neglect]].<ref>Kahneman, Daniel. (2000). "Evaluation by moments, past and future". In Daniel Kahneman and Amos Tversky (Eds.). ''Choices, Values and Frames.''</ref>
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| ==Joint versus separate evaluation==
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| In some experimental demonstrations the conjoint option is evaluated separately from its basic option. In other words, one group of participants is asked to rank order the likelihood that Linda is a bank teller, a high school teacher, and several other options, and another group is asked to rank order whether Linda is a bank teller and active in the feminist movement versus the same set of options (without Linda is a bankteller as an option). In this type of demonstration different groups of subjects rank order Linda as a bank teller and active in the feminist movement more highly than Linda as a bank teller.<ref name="tk83"/>
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| Separate evaluation experiments preceded the earliest joint evaluation experiments, and Kahneman and Tversky were surprised when the effect was still observed under joint evaluation.<ref name="tk2011-15">{{cite book |last=Kahneman |first=Daniel |title=Thinking, Fast and Slow |chapter=Linda: Less is More |year=2011 |publisher=Farrar, Straus and Giroux |location=New York |isbn= |pages=156–165 }}</ref>
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| In separate evaluation the term '''conjunction effect''' may be preferred.<ref name="tk83" />
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| ==Criticism of the Linda problem==
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| Critics such as [[Gerd Gigerenzer]] and [[Ralph Hertwig]] criticized the Linda problem on grounds such as the [[wording effect|wording]] and [[framing effect|framing]]. The question of the Linda problem may violate [[conversational maxim]]s in that people assume that the question obeys the maxim of relevance. Gigerenzer argues that some of the terminology used have [[polysemy|polysemous]] meanings, the alternatives of which he claimed were more "natural". He argues that the meaning of ''probable'' “what happens frequently”, corresponds to the mathematical probability people are supposed to be tested on, but the meanings of probable “what is plausible”, and “whether there is evidence” do not.<ref name="Gigerenzer (1996)">Gigerenzer, G. (1996). On narrow norms and vague heuristics: A reply to Kahneman and Tversky. Psychological Review, 103, 592-596.</ref><ref name="Hertwig & Gigerenzer (1999)">{{cite journal|last=Hertwig|first=Ralph|coauthors=Gerd Gigerenzer|title=The ‘Conjunction Fallacy’ Revisited: How Intelligent Inferences Look Like Reasoning Errors|journal=Journal of Behavioral Decision Making|year=1999|volume=12|pages=275–305}}</ref> The term "and" has even been argued to have relevant polysemous meanings.<ref name="Mellers, Hertwig & Kahneman (2001)">{{cite journal|last=Mellers|first=Barbara|authorlink=Barbara Mellers|coauthors=Ralph Hertwig & Daniel Kahneman|title=Do frequency representations eliminate conjunction effects? An exercise in adversarial collaboration|journal=Psychological Science|year=2001|volume=12|issue=4|pages=269–275|url=http://cds.unibas.ch/~hertwig/pdfs/2001/Mellersetal2001_frequency_eliminate_conjunction.pdf}}</ref> Many techniques have been developed to control for this possible misinterpretation but none of them has dissipated the effect.<ref name="Moro, 2009">Moro, R. (2009). On the nature of the conjunction fallacy. Synthese, 171,1–24.</ref><ref name="Tentori & Crupi, 2012">Tentori, K. & Crupi, V. (2012). On the conjunction fallacy and the meaning of and, yet again: A reply to Hertwig, Benz, and Krauss (2008). Cognition, 122, 123–134.</ref>
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| Many variations in wording of the Linda problem were studied by Tversky and Kahneman.<ref name="tk83"/> If the first option is changed to obey conversational relevance, i.e., "Linda is a bank teller whether or not she is active in the feminist movement" the effect is decreased, but the majority (57%) of the respondents still commit the conjunction error. If the probability is changed to frequency format (''see debiasing section below'') the effect is reduced or eliminated. However, studies exist in which indistinguishable conjunction fallacy rates have been observed with stimuli framed in terms of probabilities versus frequencies.<ref>See, for example, Tentori, K., Bonini, N., & Osherson, D. (2004). The conjunction fallacy: A misunderstanding about conjunction? Cognitive Science, 28, 467–477. Or Weddell & Moro, 2008.{{full|date=December 2013}}</ref>
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| The wording criticisms may be less applicable to the conjunction effect in separate evaluation.{{vague|date=February 2013}}<ref name="Gigerenzer (1996)" /> The "Linda problem" has been studied and criticized more than other types of demonstration of the effect (some described below).<ref name="tk2011-15" /><ref name="Kahneman & Tversky (1996)">Kahneman, D., & Tversky, A. (1996). On the reality of cognitive illusions. Psychological Review, 103, 582-591.</ref><ref name="Mellers, Hertwig & Kahneman (2001)" />
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| ==Other demonstrations==
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| Policy experts were asked to rate the probability that the [[Soviet Union]] would invade [[Poland]], and the [[United States]] would break off [[diplomatic relations]], all in the following year. They rated it on average as having a 4% probability of occurring. Another group of experts was asked to rate the probability simply that the United States would break off relations with the Soviet Union in the following year. They gave it an average probability of only 1%.<ref name="tk83"/>
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| In an experiment conducted in 1980, respondents were asked the following:
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| <blockquote>Suppose [[Björn Borg]] reaches the [[The Championships, Wimbledon|Wimbledon]] finals in 1981. Please rank order the following outcomes from most to least likely. | |
| * Borg will win the match
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| * Borg will lose the first set
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| * Borg will lose the first set but win the match
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| * Borg will win the first set but lose the match</blockquote>
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| On average, participants rated "Borg will lose the first set but win the match" more highly than "Borg will lose the first set".<ref name="tk83" />
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| In another experiment, participants were asked:
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| <blockquote><p>Consider a regular six-sided die with four green faces and two red faces. The die will be rolled 20 times and the sequence of greens (G) and reds (R) will be recorded. You are asked to select one sequence, from a set of three, and you will win $25 if the sequence you choose appears on successive rolls of the die.</p>
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| # RGRRR | |
| # GRGRRR
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| # GRRRRR</blockquote>
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| 65% of participants chose the second sequence, though option 1 is contained within it and is shorter than the other options. In a version where the $25 bet was only hypothetical the results did not significantly differ. Tversky and Kahneman argued that sequence 2 appears "representative" of a chance sequence<ref name="tk83"/> (compare to the ''[[clustering illusion]]'').
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| ==Debiasing==
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| Drawing attention to set relationships, using [[frequentism|frequencies]] instead of probabilities and/or thinking [[venn diagram|diagrammatically]] sharply reduce the error in some forms of the conjunction fallacy.<ref name="tk83" /><ref name="Gigerenzer (1991)" /><ref name="Hertwig & Gigerenzer (1999)" /><ref name="Mellers, Hertwig & Kahneman (2001)" />
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| In one experiment the question of the Linda problem was reformulated as follows:
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| <blockquote><p>There are 100 persons who fit the description above (that is, Linda’s). How many of them are:</p> | |
| * Bank tellers? __ of 100
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| * Bank tellers and active in the feminist movement? __ of 100</blockquote>
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| Whereas previously 85% of participants gave the wrong answer (bank teller and active in the feminist movement) in experiments done with this questioning none of the participants gave a wrong answer.<ref name="Gigerenzer (1991)">{{cite journal |last=Gigerenzer |first=G. |year=1991 |title=How to make cognitive illusions disappear: Beyond ‘heuristics and biases.’ |journal=European Review of Social Psychology |volume=2 |issue=1 |pages=83–115 |doi=10.1080/14792779143000033 }}</ref>
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| ==References==
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| {{reflist|30em}}
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| ==External links==
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| * [http://www.fallacyfiles.org/conjunct.html Fallacy files: Conjunction fallacy]
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| {{Informal_Fallacy}}
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| [[Category:Logical fallacies]]
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| [[Category:Cognitive biases]]
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5Jj1OK Brazil 6s 0d72pVfI
Mine are at 31.5 volts. If you pull the pack below the cutoff voltage, it WILL damage the pack. A few weeks ago, a colleague sent me a link to an article in the Wall Street Journal. It described a "laboratory adept European entrepreneur" and his chief chemist, who were mining the scientific literature to find ideas for new designer drugs dubbed legal highs.
In other words, the command to contract the biceps provokes another command within the spine to prevent contraction of the triceps. In this way, these antagonist muscles are kept from resisting one another. There information that going to be there that can validate your story, validate the facts."Now, eight years since the accident and a killer plea, the family continues to live with what happened. Walker, who was sitting beside his sister that night, says losing his Erica has motivated him."I will always do everything for her, just knowing that she up there looking down on sport blue 6s me saying: that my brother, look what he doing now, said jordan 6 sport blue Walker.
Michael Brown rallies across the nationPhoto essay: Police and protesters in FergusonCardinals hold off Marlins, 5 2A fifth night of unrest in FergusonA fifth day of rallies and protests in FergusonPlayers to watch galleryDoctor John's Adult Boutique started as a lingerie outlet in 1987 and expanded into an adult novelties by request but then growing into selling club apparel and shoes. We pride ourselves in customer service and a very knowledgeable staff.
The next important milestone we completed this quarter was sport blue 6s the announcement of the three months data from the pharm/tox primate study. This was the first time point in the 12 month study, and so we're not necessarily looking for efficacy data. I am a 78 year old woman who was diagnosed with PD in March and given a prescription for carbidopa/levodopa. A second opinion in June confirmed the diagnosis, but I am reluctant to start taking the meds.
相关的主题文章: