Does the employee think that rewards are likely if he or she puts in the effort?
Employees expend energy in ways that are expected to provide positive outcomes. That is, if your manager asks you to stay late and finish a report, you might do this only if you perceive that there is a positive reward for doing so (you will feel proud and satisfied, or your manager will view you as an asset and provide some reward such as praise or a bonus) or a negative reward for not doing so (you will feel ashamed, or you could be chastised or fired). If no consequence exists for your behavior, your motivation to stay late will be diminished.