Generosity in loss and gain dictator games - mediated by prepayment mechanism

We have a between subjects, 2 X 3 design. We are testing giving amount in losses and gains of the dictator game, but with a mediation of the payment mechanism (3 levels). The dependent variable is the amount kept by the dictator which is impacted by the loss or gain condition, and when the participant is given the money (prepayment - 10 days before dictator game, pre-decision - day of experiment right before they are asked to act as dictator in dictator game, post-decision - day of the experiment after they act as dictator).