in our field study and helps with the interpretation of the results.
Suppose that a worker’s preferences are represented by the following quasi-linear utility function:
(1)
U(y,e,g)= y - C (e) + 7 (e) + φ {g)
where y is income, e is effort supplied and g is a public good the worker cares about. The cost
of exerting effort is captured by the convex cost function, C (∙). The utility function in (1) embeds
both a concern for material compensation as well as the two sources of pro-social motivation that
are of interest here. Action-oriented altruism is captured by the concave function, 7 (∙) , which
represents the enjoyment the worker receives when effort contributes to the production of a good
or service she considers socially worthwhile. Output-oriented altruism is captured by the the last
term in the utility function, the concave function φ (∙), which implies that the worker is concerned
about the total quantity of a public good, g, that is provided.11 Notice that the worker’s effort may
directly contribute to the amount of public good, that is, g = g (e; ε), where ε represents a vector
of other inputs in the production of the public good.
Suppose that the worker’s income is y = к + ep, where p is a piece rate the worker receives for
each unit of output∕effort, and к represents income from other sources plus possibly a lump-sum
payment related to the job. We examine effort provision in three different settings.
First, the baseline case, where the worker’s effort is unrelated to the production of the public
good so both sources of pro-social behavior are absent. Then equilibrium effort is given by:
(2)
e* s.t. C (e*) = p,
namely, where the marginal cost of effort is equated to the marginal private return of effort. This
case corresponds to the Baseline Treatment in our experimental design.
Second, the action-oriented case, where worker’s effort takes place in an environment that is
associated with the production of the public good but where effort does not directly affect the
quantity of the public good. Then equilibrium effort is given by:
(3) ê s.t. C (ê) = p + 7' (e),
11In the interest of clarity we present here the separable case. However, what follows does not rely on the separability
of the two effects. It holds under a more general specification where the two effects are not additively separable
U(y,e,g) = y - c (e) + π(e,g), where fɪ > 0, -fjj > 0 and . < 0.