Can a group be an orthodox rational agent? This requires the group's aggregate preferences to follow expected utility (static rationality) and to evolve by Bayesian updating (dynamic rationality). Group rationality is possible, but the only preference aggregation rules which achieve it (and are minimally Paretian and continuous) are the linear-geometric rules, which combine individual values linearly and combine individual beliefs geometrically. Linear-geometric preference aggregation contrasts with classic linear-linear preference aggregation, which combines both values and beliefs linearly, but achieves only static rationality. Our characterisation of linear-geometric preference aggregation has two corollaries: a characterisation of linear aggregation of values (Harsanyi's Theorem) and a characterisation of geometric aggregation of beliefs.
Can a group be an orthodox rational agent? This requires the group's aggregate preferences to follow expected utility (static rationality) and to evolve by Bayesian updating (dynamic rationality). Group rationality is possible, but the only preference aggregation rules which achieve it (and are minimally Paretian and continuous) are the linear-geometric rules, which combine individual values linearly and combine individual beliefs geometrically. Linear-geometric preference aggregation contrasts with classic linear-linear preference aggregation, which combines both values and beliefs linearly, but achieves only static rationality. Our characterisation of linear-geometric preference aggregation has two corollaries: a characterisation of linear aggregation of values (Harsanyi's Theorem) and a characterisation of geometric aggregation of beliefs.
Titre
en
Fully Bayesian Aggregation
Auteur(s)
Franz Dietrich1, 2, 3
1
CNRS -
Centre National de la Recherche Scientifique
( 441569 )
- France
2
PSE -
Paris School of Economics
( 301309 )
- 48 boulevard Jourdan 75014 Paris
- France
Université Paris 1 Panthéon-Sorbonne ( 7550 )
;
École normale supérieure - Paris ( 59704 )
;
Université Paris Sciences et Lettres ( 564132 )
;
École des hautes études en sciences sociales ( 99539 )
;
École des Ponts ParisTech ( 301545 )
;
Centre National de la Recherche Scientifique ( 441569 )
;
Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement ( 577435 )
3
CES -
Centre d'économie de la Sorbonne
( 15080 )
- Maison des Sciences Économiques - 106-112 Boulevard de l'Hôpital - 75647 Paris Cedex 13
- France
Université Paris 1 Panthéon-Sorbonne UMR8174 ( 7550 )
;
Centre National de la Recherche Scientifique UMR8174 ( 441569 )
Langue du document
Anglais
Nom de la revue
Journal of Economic Theory
(ISSN : 0022-0531, ISSN électronique : 1095-7235)
Publié par Elsevier
Revue non référencée dans Sherpa-Romeo
Vulgarisation
Non
Comité de lecture
Oui
Audience
Internationale
Date de publication
2021
Commentaire
An earlier version was titled ‘The Rational Group’. https://hal.archives-ouvertes.fr/halshs-02431868v1