IDEAS home Printed from
   My bibliography  Save this paper

The Hangman's Paradox and Newcomb's Paradox as Psychological Games



We present a (hopefully) fresh interpretation of the Hangman's Paradox and Newcomb's Paradox by casting the puzzles in the language of modern game theory, instead of in the realm of epistemology. Game theory moves the analysis away from the formal logic of the puzzles toward more practical problems, such as: On what day would the executioner hang the prisoner if he wanted to surprise him as much as possible? How should a surprise test be administered? We argue that both the Hangman's Paradox and Newcomb's Paradox are analogous to a well-known phenomenon in game theory, that giving a player an additional attractive (even dominant) strategy may make him worse off. In the Hangman's Paradox, the executioner is determined to surprise the prisoner as much as possible, yet he cannot surprise him at all because he cannot commit in advance to a random schedule. The possibility of changing his mind (i.e., the presence of alternative strategies) superficially would seem to help the executioner, but because it changes the expectations of the prisoner, in the end it works dramatically to his disadvantage. In Newcomb's Paradox, a man given an extra dominant choice is worse off because it changes God's expectations about what he will do. Our analysis cannot be couched in terms of the standard Nash framework of games, but must instead be put in a recent extension called psychological games, where payoffs may depend on beliefs as well as on actions.

Suggested Citation

  • John Geanakoplos, 1996. "The Hangman's Paradox and Newcomb's Paradox as Psychological Games," Cowles Foundation Discussion Papers 1128, Cowles Foundation for Research in Economics, Yale University.
  • Handle: RePEc:cwl:cwldpp:1128

    Download full text from publisher

    File URL:
    Download Restriction: no

    References listed on IDEAS

    1. Gilboa, Itzhak & Schmeidler, David, 1988. "Information dependent games : Can common sense be common knowledge?," Economics Letters, Elsevier, vol. 27(3), pages 215-221.
    2. Geanakoplos, John & Pearce, David & Stacchetti, Ennio, 1989. "Psychological games and sequential rationality," Games and Economic Behavior, Elsevier, vol. 1(1), pages 60-79, March.
    3. Werlang, Sérgio Ribeiro da Costa, 1988. "Common knowledge," FGV/EPGE Economics Working Papers (Ensaios Economicos da EPGE) 118, FGV/EPGE - Escola Brasileira de Economia e Finanças, Getulio Vargas Foundation (Brazil).
    Full references (including those not matched with items on IDEAS)


    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.

    Cited by:

    1. Battigalli, Pierpaolo & Dufwenberg, Martin, 2009. "Dynamic psychological games," Journal of Economic Theory, Elsevier, vol. 144(1), pages 1-35, January.
    2. Peter Hans Matthews, 2004. "Who is Post-Walrasian Man?," Middlebury College Working Paper Series 0412, Middlebury College, Department of Economics.

    More about this item


    Access and download statistics


    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:cwl:cwldpp:1128. 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: (Matthew Regan). General contact details of provider: .

    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 CitEc recognized a reference but did not link an item in RePEc 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 RePEc Author Service 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.

    IDEAS is a RePEc service hosted by the Research Division of the Federal Reserve Bank of St. Louis . RePEc uses bibliographic data supplied by the respective publishers.