IDEAS home Printed from https://ideas.repec.org/p/hal/wpaper/hal-04990911.html
   My bibliography  Save this paper

The disjunction effect does not violate the Law of Total Probability

Author

Listed:
  • Alexandros Gelastopoulos

    (TSE-R - Toulouse School of Economics - UT Capitole - Université Toulouse Capitole - UT - Université de Toulouse - EHESS - École des hautes études en sciences sociales - CNRS - Centre National de la Recherche Scientifique - INRAE - Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement)

  • Gael Le Mens

    (university of pompeu fabra)

Abstract

The disjunction effect (DE) refers to an empirical violation of the Sure-Thing Principle (STP), which states that if a person is willing to take an action independently of the outcome of some event, then they must be willing to do so even when the outcome of the event is unknown. A standard practice for inferring a DE, especially in between-subjects experiments, consists of showing a population-level version of this phenomenon, specifically that fewer people are willing to take the proposed action when the outcome of the event is unknown than for any possible known outcome. Although this does not prove a violation of the STP, this population-level condition has received a lot of attention, because it presumably violates the Law of Total Probability, and it is sometimes used as the definition of the DE itself. Here we show that this condition is in fact unrelated to the Law of Total Probability and thus entirely irrelevant for the study of the DE and decision making in general. This calls for a reevaluation of experimental results that have been interpreted as showing a DE based on the above condition. We derive a new disjunction law that can be used to check for violations of the STP in between-subjects data.

Suggested Citation

  • Alexandros Gelastopoulos & Gael Le Mens, 2025. "The disjunction effect does not violate the Law of Total Probability," Working Papers hal-04990911, HAL.
    • Handle: RePEc:hal:wpaper:hal-04990911
    Note: View the original document on HAL open archive server: https://hal.science/hal-04990911v1
    as

    Download full text from publisher

    File URL: https://hal.science/hal-04990911v1/document
    Download Restriction: no
    ---><---

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:hal:wpaper:hal-04990911. See general information about how to correct material in RePEc.

    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.

    We have no bibliographic references for this item. You can help adding them by using 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 RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: CCSD (email available below). General contact details of provider: https://hal.archives-ouvertes.fr/ .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.