Final answer:
The restorative theory holds that sleep functions to restore the body and brain from the day's wear and tear, predicting a positive correlation between activity levels and sleep duration.
Step-by-step explanation:
The theory that posits sleep as a time for restoration and recovery from the wear and tear experienced while awake is known as the restorative theory. If this theory holds true, one would predict a direct relationship between an individual's total sleep duration and their level of daily activity. More active individuals would require longer periods of sleep to recover from their energetic expenditures. In contrast, less active individuals might need less sleep, as they have expended less energy during the day. However, research has actually found a negative correlation between energetic demands and the amount of time spent sleeping, challenging the straightforward restorative hypothesis of sleep.