Sleep and Why We Sleep

Critical Thinking Questions

If theories that assert sleep is necessary for restoration and recovery from daily energetic demands are correct, what do you predict about the relationship that would exist between individuals’ total sleep duration and their level of activity?


Those individuals (or species) that expend the greatest amounts of energy would require the longest periods of sleep.

How could researchers determine if given areas of the brain are involved in the regulation of sleep?


Researchers could use lesion or brain stimulation techniques to determine how deactivation or activation of a given brain region affects behavior. Furthermore, researchers could use any number of brain imaging techniques like fMRI or CT scans to come to these conclusions.

Differentiate the evolutionary theories of sleep and make a case for the one with the most compelling evidence.


One evolutionary theory of sleep holds that sleep is essential for restoration of resources that are expended during the demands of day-to-day life. A second theory proposes that our sleep patterns evolved as an adaptive response to predatory risks, which increase in darkness. The first theory has little or no empirical support, and the second theory is supported by some, though not all, research.