We all need to make plans for the future, and many of those plans involve estimating time. If I have to write a grant proposal before a deadline, I need to make a reasonable estimate of the amount of time that it will take to complete the proposal in order to fit it into my schedule. A manager at a company needs to figure out how long a project will take in order to allocate the right number of people to ensure it is completed.
One factor that may influence your judgments of the amount of time a project will take is the amount of time it will take before you start the project. At times, you may be planning for a project you are about to start in the next few days. At other times, though, you are budgeting your time off into the future.
An interesting paper in 2011 by Alf Kanten published in the Journal of Experimental Social Psychology addressed this question.
One way that you figure out how long a project will take is to figure out how much work you can get done in each unit of time. Think back to what you did yesterday. Each event can be remembered in some detail. As a result, each hour feels like it was relatively long. But, if you try to think back to a day 6 months ago, it is hard to call up a lot of vivid details, and so each hour does not feel as packed with events. As a result, hours in the distant past feel shorter (psychologically) than hours from the recent past.
Kanten found this works in the forward direction too. People were given a line and were asked to place a mark on the line to indicate their feeling about the perceived length of an hour. Before making this estimate, the participants were either induced to think abstractly or to think concretely. Quite a bit of research by Nira Liberman, Yaacov Trope and their colleagues suggests that when things are distant from you in time, then you think about them more abstractly than when they are near to you. Participants who were thinking abstractly marked a shorter length for an hour than those who marked a longer length.
How does this difference in the perception of time affect judgments about how long a project will take?
In another study, participants judged how long a project would take. For example, college students were asked to imagine they had been assigned to read a chapter of a history book and to write a summary of it. Others were asked to imagine cleaning their apartment. Some participants had to imagine starting the project tomorrow, while others were asked to imagine doing it some time the following year.
People judged that the project would take longer if they had to do it in the distant future than if they had to do it tomorrow. That is, if each hour feels shorter in the future, then you can get less work done in each hour, and so it will require more hours to complete the project.
It is probably good that we are biased to think that projects will take longer in the future than in the present. When planning, it is generally a good idea to be overly cautious. After all, it is worse to leave too little time for a project than to leave too much.