Afternoon slumps nothing to do with time of day


Our self-control may not be a finite resource that diminishes throughout the day but we may still experience fatigue while persisting in a single task, a new study has found.

Previous studies have suggested that we have a finite resource of self-control, and thus have theorised that our motivation for cognitively challenging activities will deplete throughout the day.

However, recent attempts to demonstrate people losing motivation on tasks throughout an entire day have failed to yield sufficient evidence to support this theory.

Daniel Randles from the University of Toronto and colleagues decided to investigate whether we have a finite amount of self-control by monitoring two groups of students (N1 = 8,867, N2 = 8,754) over separate 17-week intervals with 24-hour coverage, as they engaged in voluntary learning and self-testing using an online program.

The researchers assessed what time the students logged into the program, how long they persisted at a session, and how successful they were at the memory tests, and constructed a model from this data.

They found that time of day had very little effect on students’ success at completing the tasks, which is contrary to the theory that our self-control depletes throughout the day.

The researchers found that a student could concentrate on a single task for about an hour before their performance depleted on that specific task, which is consistent with previous research, but the time of day at which the task was performed did not affect performance.

In order to access this information, this study did not consider demographics or what the students thought about the task, which the authors suggest would be important details to allow for a more complete interpretation of the results.

However, they maintain that this research casts some serious doubt on the theory that we have a limited reservoir of self-control to draw from throughout the day, and hopefully opens the door for additional studies on motivation.