How to reconcile financial incentives and pro-social motivation of loan officers in microfinance?

More and more double bottom line microfinance institutions, which
pursue both social and financial objectives, have adopted an incentive scheme
to motivate their credit officers to improve their financial performance. How-
ever, the crowding-out hypothesis, developed by some psychologists, suggests
that monetary rewards may not always be optimal as they may reduce proso-
cial motivation. Therefore, according to this theory, loan officers may be less
willing to take care about clients when receiving financial incentives, what
might then jeopardize the social mission of the micronance institution. In
this paper, we attempt to suggest, with a mathematical model, an optimal
incentive scheme microfinance institutions could rely on in order to increase
their financial performance while preserving loan officers' prosocial motivation.