From group diffusion to ratio bias
The group-diffusion effect is the tendency for people to judge themselves to be less likely to experience a negative outcome as the total number of people exposed to the threat increases --- even when the probability of the outcome is explicitly presented (Yamaguchi, 1998). In Experiment 1 we replic...
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Format: | Article |
Language: | English |
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Cambridge University Press
2009-10-01
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Series: | Judgment and Decision Making |
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Online Access: | http://journal.sjdm.org/9430/jdm9430.pdf |
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author | Paul C. Price Teri V. Matthews |
author_facet | Paul C. Price Teri V. Matthews |
author_sort | Paul C. Price |
collection | DOAJ |
description | The group-diffusion effect is the tendency for people to judge themselves to be less likely to experience a negative outcome as the total number of people exposed to the threat increases --- even when the probability of the outcome is explicitly presented (Yamaguchi, 1998). In Experiment 1 we replicated this effect for two health threat scenarios using a variant of Yamaguchi's original experimental paradigm. In Experiment 2, we showed that people also judge themselves to be less likely to be selected in a lottery as the number of people playing the lottery increases. In Experiment 3, we showed that explicitly presenting the number of people expected to be selected eliminates the group-diffusion effect, and in Experiment 4 we showed that presenting the number expected to be affected by a health threat without presenting the total number exposed to the threat produces a reverse effect. We propose, therefore, that the group-diffusion effect is related to the ratio bias. Both effects occur when people make risk or likelihood judgments based on information presented as a ratio. The difference is that the group-diffusion effect occurs when the denominator of the relevant ratio is more salient than the numerator, while the ratio bias occurs when the numerator is more salient than the denominator. |
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id | doaj.art-f8e12e760a11497c87729f188c903efa |
institution | Directory Open Access Journal |
issn | 1930-2975 |
language | English |
last_indexed | 2024-03-12T04:15:39Z |
publishDate | 2009-10-01 |
publisher | Cambridge University Press |
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series | Judgment and Decision Making |
spelling | doaj.art-f8e12e760a11497c87729f188c903efa2023-09-03T10:41:11ZengCambridge University PressJudgment and Decision Making1930-29752009-10-0146436446From group diffusion to ratio biasPaul C. PriceTeri V. MatthewsThe group-diffusion effect is the tendency for people to judge themselves to be less likely to experience a negative outcome as the total number of people exposed to the threat increases --- even when the probability of the outcome is explicitly presented (Yamaguchi, 1998). In Experiment 1 we replicated this effect for two health threat scenarios using a variant of Yamaguchi's original experimental paradigm. In Experiment 2, we showed that people also judge themselves to be less likely to be selected in a lottery as the number of people playing the lottery increases. In Experiment 3, we showed that explicitly presenting the number of people expected to be selected eliminates the group-diffusion effect, and in Experiment 4 we showed that presenting the number expected to be affected by a health threat without presenting the total number exposed to the threat produces a reverse effect. We propose, therefore, that the group-diffusion effect is related to the ratio bias. Both effects occur when people make risk or likelihood judgments based on information presented as a ratio. The difference is that the group-diffusion effect occurs when the denominator of the relevant ratio is more salient than the numerator, while the ratio bias occurs when the numerator is more salient than the denominator.http://journal.sjdm.org/9430/jdm9430.pdfrisk judgmentprobability judgmentgroup-diffusion effectratio bias. |
spellingShingle | Paul C. Price Teri V. Matthews From group diffusion to ratio bias Judgment and Decision Making risk judgment probability judgment group-diffusion effect ratio bias. |
title | From group diffusion to ratio bias |
title_full | From group diffusion to ratio bias |
title_fullStr | From group diffusion to ratio bias |
title_full_unstemmed | From group diffusion to ratio bias |
title_short | From group diffusion to ratio bias |
title_sort | from group diffusion to ratio bias |
topic | risk judgment probability judgment group-diffusion effect ratio bias. |
url | http://journal.sjdm.org/9430/jdm9430.pdf |
work_keys_str_mv | AT paulcprice fromgroupdiffusiontoratiobias AT terivmatthews fromgroupdiffusiontoratiobias |