Table 1.

Regression analyses of the effect of prosocial behavior on happiness, self-image, and mood in the short and long run

	Short run			Long run
Dependent variable (standardized)	1) Happiness	2) Self-image	3) Mood	4) Happiness	5) Self-image	6) Mood
Lottery choice: 1 if altruistic, 0 if selfish	0.11 (0.112)	0.41*** (0.135)	−0.62*** (0.149)	−0.05 (0.129)	0.28** (0.128)	0.17 (0.172)
Lottery outcome: 1 if life saved, 0 if money received	0.03 (0.116)	0.28** (0.132)	0.21 (0.179)	−0.29* (0.150)	0.25 (0.159)	0.14 (0.190)
Altruistic lottery choice $\times$ life saved	0.06 (0.159)	−0.05 (0.166)	1.16*** (0.212)	0.06 (0.190)	−0.27 (0.193)	−0.14 (0.235)
Baseline happiness (at beginning of session)	0.77*** (0.065)			0.61*** (0.056)
Baseline self-image (at beginning of session)		0.52*** (0.033)			0.46*** (0.041)
Baseline mood (at beginning of session)			0.10** (0.037)			0.18*** (0.041)
Constant	−3.65*** (0.316)	−4.45*** (0.279)	−0.84*** (0.302)	−2.64*** (0.294)	−3.83*** (0.344)	−1.47*** (0.356)
Main effect choice: altruistic lottery	0.14*	0.38***	–0.04	–0.02	0.14	0.11
$\hookrightarrow$ short run = long run				2.29	4.76**	0.94
(${\chi }^2$ statistic)
Main effect outcome: life saved	0.06*	0.25***	0.78***	–0.26***	0.12	0.07
$\hookrightarrow$ short run = long run				8.39***	1.44	24.34***
(${\chi }^2$ statistic)
$R^{\mathit{\text{2}}}$	0.5426	0.5564	0.3127	0.3642	0.391	0.08326
N	297	297	297	297	297	297

Displayed are regression results that complement the findings in Fig. 2 using ordinary least squares. Columns 1 to 3 present the short-run results, and columns 4 to 6 present the long-run results. In each column, we regressed a standardized happiness score, self-image score, or mood score on an indicator variable that equals one if a subject chose the prosocial lottery and zero otherwise (row 1); an indicator variable that is one if the subject’s lottery draw determined that she would save a life and zero if she received the money (row 2); a term capturing the interaction between these two variables (row 3); and the standardized baseline level of the dependent measure (rows 4 to 6). All regressions include a constant. Analogous ordered probit regressions are reported in SI Appendix, Table S2. Robust SEs are in parentheses. The asterisks indicate significance levels of two-sided t tests for the null hypothesis that the regression coefficient equals zero. The table also displays F tests unless indicated otherwise. *P < 0.1; *P < 0.05; *P < 0.01.