No amount of lecturing seems to persuade students to get more sleep.

But one professor uses bait they can't resist.

Michael Scullin teaches the science of sleep to psychology students at Baylor University in Waco, Texas. He lectures about physical and mental health problems caused by a lack of sleep. Those problems include difficulty focusing and controlling one's emotions, and increased risk of disease.

"When you are at your most sleep deprived is when you are least likely to be able to judge how sleepy you are, and how much that sleepiness is impacting you," Scullin says.

The U.S. Centers for Disease Control and Prevention advises adults to get at least seven hours of sleep a night to stay healthy, but more and more Americans report getting fewer than six hours of sleep per night.

His students seemed to enjoy the class, Scullin says. But when he asked if they were getting more sleep after what they learned in class, most of them said no.

So Scullin came up with a plan to get his students to sleep more: He offered them extra points on their final exam, the most important test in the class.

The plan worked better than Scullin expected. Students who slept more performed better in two different classes, and Scullin published his findings in two academic publications last November.

​How did the study work?

Scullin started the experiment with his psychology students. He told them that if they agreed to sleep at least eight hours a night for the five nights before the final exam, they would get several extra credit points. But if they agreed to take part in the study and failed to get the required amount of sleep, they would lose points on the exam. The students would wear special devices that recorded their sleep data.

Only eight out of the 18 total students in that first group agreed to take part in the experiment. Yet all the students who took part performed better on the exam than those who did not, even before the extra credit points were added. On average, they earned about five points more on the exam.

Scullin decided to repeat the study with another group of 16 design students. He chose not to punish students who failed to sleep the full eight hours per night, and got the same results.

Daniel Bessesen, as associate director of the Anschutz Health and Wellness Center at the University of Colorado, researches sleep. He says Scullin's study supports the idea that sleep helps academic performance while students who cram — or stay up the night before the test trying to memorize the material — are likely worse off.

While Scullin's study fits in with other sleep research, Bessesen says for it to be more scientific, the two groups should have been studying the same subject and taking the same test. In addition, students should have been randomly chosen for sleeping or staying awake.

How to get people to sleep more

Scullin and Bessesen offer some advice on how to get more sleep each night:

• Parents, try to get enough sleep to role model good habits to children. Bessesen notes that some medical school programs require student doctors to sleep more to prevent accidents.
• Avoid looking at electronics before you fall asleep.
• Don't consume caffeinated drinks less than six hours before you go to sleep.
• Try to go to sleep at the same time every night.
• If you are lying in bed and cannot calm your mind, get out of bed and spend five to 10 minutes writing down all of your thoughts.
• If you wake up in the middle of the night and cannot fall back asleep, do not turn on the lights! Instead, get out of bed and go into another room. Wait there until you feel tired.