Mental accounting

Mental accounting is the tendency for people to categorize and treat money differently according to trivial factors such as where the money originated from, where it is being spent, and its form, as opposed to its absolute value. Mental accounting acts against the idea of fungibility (i.e. all money is interchangeable and has no labels). Instead, people compartmentalize money according to subconciously assigned labels. For instance, one may treat $100 that they found on the ground much differently than $100 received as income.