 Model  
Variable  I  II  III 
Exogenous Index (X)  13.386 (3.186) [0.000]  −28.451 (27.629) [0.303] 

Endogenous Index (N) 
 −2.361 (7.454) [0.751]  5.868 (1.424) [0.000] 
Interaction of Exogenous & Endogenous Indices (XxN) 
 35.047 (33.875) [0.301] 

Social Value Orientation (slope of resultant vector)
 0.402 (0.535) [0.451]  1.356 (0.780) [0.082]  0.956 (0.556) [0.085] 
Risk Averse (=1, =0 otherwise)
 0.736 (1.014) [0.468]  1.305 (1.055) [0.216]  1.157 (1.117) [0.300] 
Risk Seeking (=1, =0 otherwise)
 0.986 (0.572) [0.091]  0.515 (0.758) [0.497]  0.523 (0.664) [0.431] 
Constant (Pro Self, Risk Neutral Participants)
 −4.076 (1.106) [0.000]  2.037 (5.449) [0.709]  −4.353 (1.192) [0.000] 
Pseudo Rsquared pvalue for χ^{2}test on Model Significance  0.457 0.001  0.595 0.032  0.567 0.001 
Test: the coefficients of X and XxN are not different from zero (the main effect X) 
 χ^{2} = 1.08 p = 0.584 

Test: the coefficients of N and XxN are not different from zero (the main effect of N) 
 χ^{2} = 7.80 p = 0.020 
