According to a study by James Heyman and Dan Ariely in 2004, there are two types of markets that determine relationships between effort and payment – monetary and social. The study measured how motivated a person was when it comes to complete a task based on monetary rewards. For the study, subjects were asked to drag circles across a computer screen.
One group was asked to do this as a favor. Another group was asked to do it for $0.50, and the last group was offered $5. After timing the subjects, it was actually the group asked to perform the task as a favor that did it the fastest. Next was the $5 group, and last was the $0.50 group.
Through this study, we can note that money influences how we value or perceive time. For instance, doing a favour for free might come with a positive/feel-good feeling and hence, you might want to give it your best shot (or at least, quickest so you can get it out of the way).
However, when money is introduced or tied to a task, you might feel a sense of entitlement and this could affect the way you work.