glow motivation for charitable giving. In our setting, we are interested in measuring the strength
of the action-oriented motivation for making labor donations, so in this treatment we told subjects
that besides their personal compensation, which remained the same as in the first occasion, their
effort could contribute to a charity of their choice, but their contribution would perfectly crowd out
our contribution so that the total amount the charity received was fixed at £15. Given the nature of
the donation any additional effort that the students might provide in this treatment, relative to the
baseline treatment, can be solely attributed to action-oriented intrinsic motivation. In treatment B,
we told subjects that besides their personal compensation, which remained the same as in the first
occasion, their effort could contribute to a charity of their choice with no crowding out taking place,
so that the total donation that the charity received depended on their effort. In this treatment,
both sources of pro-social behavior are elicited. Therefore, any additional effort that we observe in
this treatment relative to treatment A can be attributed solely to output-oriented altruism.
We found that effort is positively affected by an environment that induces action-oriented altru-
ism, while there is no additional impact due to output-oriented altruism. Interestingly, we found
significant gender-related differences in the treatment effect. In particular, our results suggest that
women are very responsive to the treatment condition eliciting action-oriented altruism, increasing
their productivity between the two sessions by an additional 14% compared to women in the control
group, while they do not display any additional increase in effort due to output-oriented altruism.
On the other hand, for male subjects, we find no statistically significant differences in productiv-
ity changes between the control and any of the treatment groups. This unresponsiveness suggests
that pro-social preferences are less relevant for men than for female workers in our sample. Our
results are consistent with those obtained in studies that have examined experimentally differences
in social preferences across genders.4
The rest of the paper is organized as follows: the next section presents the experimental design.
Section 3 discusses the conceptual framework we use and derives the behavioral predictions. Section
4 presents the results of the study and section 5 offers some concluding remarks.
4See Camerer (2003) and Croson and Gneezy (2009) for an overview of the experimental evidence of gender
differences in social preferences.