From group diffusion to ratio bias: Effects of denominator and numerator salience on intuitive risk and likelihood judgments
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.
Volume (Year): 4 (2009)
Issue (Month): 6 (October)
|Contact details of provider:|| |
References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Jose-Luis Pinto-Prades & Jorge-Eduardo Martinez-Perez & Jose-Maria Abellan-Perpinan, 2006. "The influence of the ratio bias phenomenon on the elicitation of health states utilities," Judgment and Decision Making, Society for Judgment and Decision Making, vol. 1, pages 118-133, November.
- Jose Luis Pinto-Prades & Jorge E. Martinez Perez & Jose María Abellán Perpiñán, 2006. "The influence of the Ratio Bias phenomenon on the elicitation of Standard Gamble utilities," Working Papers 06.16, Universidad Pablo de Olavide, Department of Economics.
- Carissa Bonner & Ben R. Newell, 2008. "How to make a risk seem riskier: The ratio bias versus construal level theory," Judgment and Decision Making, Society for Judgment and Decision Making, vol. 3, pages 411-416, June.
- Donald Dale & Jeffrey Rudski & Adam Schwartz & Eric Smith, 2007. "Innumeracy and incentives: A ratio bias experiment," Judgment and Decision Making, Society for Judgment and Decision Making, vol. 2, pages 243-250, August.
When requesting a correction, please mention this item's handle: RePEc:jdm:journl:v:4:y:2009:i:6:p:436-446. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Jonathan Baron)
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.