J. Andreoni and J. Miller, Giving according to garp: An experimental test of the consistency of preferences for altruism, Econometrica, vol.70, issue.2, pp.737-753, 2002.

J. Andreoni and C. Sprenger, Uncertainty equivalents: Testing the limits of the independence axiom, 2011.

D. Ariely, A. Bracha, M. , and S. , Doing good or doing well? image motivation and monetary incentives in behaving prosocially, American Economic Review, vol.99, issue.1, pp.544-55, 2009.
DOI : 10.1257/aer.99.1.544

URL : http://www.bostonfed.org/economic/wp/wp2007/wp0709.pdf

O. Bock, I. Baetge, and A. Nicklisch, hroot: Hamburg registration and organization online tool, European Economic Review, vol.71, pp.117-120, 2014.
DOI : 10.1016/j.euroecorev.2014.07.003

G. E. Bolton and A. Ockenfels, Erc: A theory of equity, reciprocity, and competition, American Economic Review, vol.90, issue.1, pp.166-193, 2000.
DOI : 10.1257/aer.90.1.166

URL : http://www.dklevine.com/archive/erc1.pdf

J. M. Brock, A. Lange, and E. Y. Ozbay, Dictating the risk: Experimental evidence on giving in risky environments, American Economic Review, vol.103, issue.1, pp.415-452, 2013.
DOI : 10.1257/aer.103.1.415

URL : https://www.aeaweb.org/aer/data/feb2013/20100497_app.pdf

E. Cettolin, A. Riedl, T. , and G. , Giving in the face of risk, Journal of Risk and Uncertainty, vol.55, issue.2, pp.95-118, 2017.

S. Chakravarty, G. W. Harrison, E. E. Haruvy, and E. E. Rutström, Are you risk averse over other people's money?, Southern Economic Journal, vol.77, issue.4, pp.901-913, 2011.
DOI : 10.4284/0038-4038-77.4.901

URL : https://web.iima.ac.in/assets/snippets/workingpaperpdf/2005-08-04sujoy.pdf

G. Charness and M. Rabin, Understanding social preferences with simple tests, Quarterly Journal of Economics, vol.117, issue.3, pp.817-869, 2002.
DOI : 10.1162/003355302760193904

URL : https://cloudfront.escholarship.org/dist/prd/content/qt0dc3k4m5/qt0dc3k4m5.pdf?t=lnr2wj

S. H. Chew, B. Miao, and S. Zhong, Partial ambiguity, Econometrica, vol.85, issue.4, pp.1239-1260, 2017.

J. Dana, D. M. Cain, and R. M. Dawes, What you don't know won't hurt me: Costly (but quiet) exit in dictator games, Organizational Behavior and human decision Processes, vol.100, issue.2, pp.193-201, 2006.

J. Dana, R. A. Weber, and J. X. Kuang, Exploiting moral wiggle room: experiments demonstrating an illusory preference for fairness, Economic Theory, vol.33, issue.1, pp.67-80, 2007.
DOI : 10.1007/s00199-006-0153-z

D. Ellsberg, Risk, ambiguity, and the savage axioms, Quarterly journal of economics, vol.75, issue.4, pp.643-669, 1961.
DOI : 10.2307/1884324

URL : http://www.dklevine.com/archive/refs47605.pdf

C. Engel, Dictator games: A meta study, Experimental Economics, vol.14, issue.4, pp.583-610, 2011.
DOI : 10.1007/s10683-011-9283-7

URL : http://www.coll.mpg.de/pdf_dat/2010_07online.pdf

K. W. Eriksen and O. Kvaløy, Do financial advisors exhibit myopic loss aversion? Financial Markets and Portfolio Management, vol.24, pp.159-170, 2010.
DOI : 10.1007/s11408-009-0124-z

C. L. Exley, Excusing selfishness in charitable giving: The role of risk, Review of Economic Studies, vol.83, issue.2, pp.587-628, 2015.

C. L. Exley, Using charity performance metrics as an excuse not to give, 2015.

E. Fehr and K. M. Schmidt, A theory of fairness, competition, and cooperation, Quarterly journal of economics, vol.114, issue.3, pp.817-868, 1999.
DOI : 10.2139/ssrn.106228

URL : http://dlc.dlib.indiana.edu/dlc/bitstream/handle/10535/6398/A%20Theory%20of%20Fairness%20Competition%20and%20Cooperation.pdf?sequence=1&isAllowed=y

I. Gilboa and D. Schmeidler, Maxmin expected utility with non-unique prior, Journal of Mathematical Economics, vol.18, issue.2, pp.141-153, 1989.
DOI : 10.1016/0304-4068(89)90018-9

URL : https://hal.archives-ouvertes.fr/hal-00753237

Z. Grossman and J. J. Van-der-weele, Self-image and willful ignorance in social decisions, Journal of the European Economic Association, vol.15, issue.1, pp.173-217, 2017.
DOI : 10.1093/jeea/jvw001

URL : https://pure.uva.nl/ws/files/35228744/jvw001.pdf

E. C. Haisley and R. A. Weber, Self-serving interpretations of ambiguity in otherregarding behavior, Games and Economic Behavior, vol.68, issue.2, pp.614-625, 2010.

J. R. Hamman, G. Loewenstein, and R. A. Weber, Self-interest through delegation: An additional rationale for the principal-agent relationship, American Economic Review, vol.100, issue.4, pp.1826-1872, 2010.
DOI : 10.1257/aer.100.4.1826

URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.343.993

E. Hoffman, K. Mccabe, and V. L. Smith, Social distance and other-regarding behavior in dictator games, American Economic Review, vol.86, issue.3, pp.653-660, 1996.

D. Kahneman, P. Slovic, and A. Tversky, Judgment under uncertainty: Heuristics and biases, 1982.

S. Klarenbach, J. Gill, G. Knoll, T. Caulfield, N. Boudville et al., Economic consequences incurred by living kidney donors: A canadian multi-center prospective study, American Journal of Transplantation, vol.14, issue.4, pp.916-922, 2014.

M. Krawczyk, L. Lec, and F. , give me a chance!'an experiment in social decision under risk, Experimental Economics, vol.13, issue.4, pp.500-511, 2010.
URL : https://hal.archives-ouvertes.fr/hal-00675500

M. J. Machina and M. Siniscalchi, Ambiguity and ambiguity aversion, Handbook of the Economics of Risk and Uncertainty, vol.1, pp.729-807, 2014.

S. Meier and C. D. Sprenger, Temporal stability of time preferences, Review of Economics and Statistics, vol.97, issue.2, pp.273-286, 2015.

P. P. Reese, N. Boudville, and A. X. Garg, Living kidney donation: outcomes, ethics, and uncertainty, The Lancet, vol.385, issue.9981, pp.2003-2013, 2015.
DOI : 10.1016/s0140-6736(14)62484-3

D. B. Reynolds, J. Joseph, S. , and R. , Risky shift versus cautious shift: determining differences in risk taking between private and public management decisionmaking, Journal of Business and Economics Research, vol.7, issue.1, pp.63-77, 2009.

, Trade-off " in models (1) and (3) are significant (p < 0.001). Result 1-R is thus robust to the exclusion of multiple switchers. Likewise, excuse-driven behavior under ambiguityfor-self is also confirmed, as the coefficients associated with "Trade-off " in models (2) and (4) are significant, Excuse-driven behavior under risk-for-self is confirmed, as the coefficients associated with

, Trade-off ": model (6) p < 0.001, model (8) p = 0.961). Result 2-R and Result 2-A are thus robust to the exclusion of multiple switchers. The coefficients associated with "Trade-off × Risk" in models (1) and (3) are not significant (p = 0.630 and p = 0.149, respectively), We find evidence of excuse-driven behavior under risk-for-charity only when including the censored subjects (coefficient associated with "Trade-off ": model (5) p < 0.001, model, vol.585, p.0

, Result 4 on the absence of reinforced excuse-driven behavior under ambiguity-for-charity compared to risk-for-charity is also supported when excluding multiple switchers