Failure to reject the Norm Hypothesis (i) gives credence to the Hypothesis that a change in a norm behavior – here, a contribution amount to a carbon offsetting program – induces self-sanctioning. The fact that the marginal effect of the norm on self-image is negative lends support to the theory purposed by Brekke rt al.(2003) in which people have lower self-image the farther below the norm contribution their own contribution to the public good is. Failure to reject the Norm Hypothesis (ii) indicates that rising the norm contribution causes people to contribute more.