Are experienced people affected by a pre-set default option—Results from a field experiment ˚ Asa L¨ ofgren a,n , Peter Martinsson a,1 , Magnus Hennlock a,b,1 , Thomas Sterner a,c,1 a Department of Economics, University of Gothenburg, Box 640, SE 405 30 Gothenburg, Sweden b Policy Development Department, Swedish Environmental Protection Agency, Valhallav¨ agen 195, 106 48 Stockholm, Sweden c Resources for the Future, Washington, DC, USA article info Article history: Received 21 October 2009 Available online 14 July 2011 Keywords: CO 2 offsetting Default option Field experiment Public goods abstract The objective of the present paper is to investigate the robustness of the well-known result that pre-set default options determine people’s choices. We do so by conducting a field experiment among environmental economists attending a large international conference on environmental economics. The participants were, at the time of registration, randomly allocated to different treatments related to carbon offsetting. What differs from earlier default studies is that our subjects have good knowledge about the good at hand. We investigate whether the choices of these experienced individuals are affected by a pre-set default option, and we also study the effect of a treatment with no pre-set default option. Our results, together with previous findings, indicate that the effect of a default option attenuates with experience. & 2011 Elsevier Inc. All rights reserved. 1. Introduction According to standard textbook economics, preferences are given. Over the years this assumption has been continuously challenged (see, e.g., [1]). The effect of pre-set default options on individual choices is an area where behavioral anomalies have been found [2]. A pre-set default option is the alternative that someone will receive if not actively making another choice, and a pre-set default option should not affect the choices made by rational subjects. The empirical evidence on default options can be summarized as the following conventional wisdom: ‘‘Overall, the finding of large default effects is one of the most robust results in the applied economics literature for the last ten years’’ ([21], p. 332). The objective of the present paper is to investigate the robustness of the conventional wisdom that a pre-set default option determines people’s choices. We do so by conducting a field experiment among environmental economists attending a large international conference on environmental economics. The participants were, at the time of registration, randomly allocated to different treatments related to carbon offsetting. What differs from earlier default studies is that our subjects have good knowledge about the good at hand. We investigate whether the choices of these experienced people are affected by a pre-set default option, and we also study the effect of a treatment with no pre-set default option. As indicated by DellaVigna [21], several studies have empirically investigated the impact of pre-set default options. Two of the more cited areas with significant effects of pre-set default options of high economic significance are organ donation [3,4] and pension saving [5]. In addition, pre-set default options have been found to affect insurance decisions [6], Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jeem Journal of Environmental Economics and Management 0095-0696/$ - see front matter & 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.jeem.2011.06.002 n Corresponding author. Fax: þ46 317864154. E-mail addresses: asa.lofgren@economics.gu.se ( ˚ A L¨ ofgren), peter.martinsson@economics.gu.se (P. Martinsson), magnus.hennlock@economics.gu.se (M. Hennlock), thomas.sterner@economics.gu.se (T. Sterner). 1 Fax: þ46 317864154. Journal of Environmental Economics and Management 63 (2012) 66–72