Discoveries Shorts

From Minnesota Alumni Magazine Winter 2018

By Elizabeth Foy Larsen

The Case for Later School Start Times


Researchers at the University of Minnesota have confirmed what parents and teachers have long suspected: Students’ mental and behavioral health improves when schools start later.

The study, which was coauthored by School of Public Health Ph.D. student (and former high school teacher) Aaron Berger, SPH Associate Professor Rachel Widome, and College of Education and Human Development senior researcher Kyla Wahlstrom, surveyed more than 9,000 students from eight high schools across the U.S. on sleep and certain health, academic, and behavioral issues. The schools in the study had start times ranging from 7:35 a.m. to 8:55 a.m.

Adolescents who attended schools with later start times reported sleeping longer, which turned out to be significant in light of the fact that for each additional hour of sleep, there was a 28 percent reduction in students who said they felt unhappy, sad, or depressed. Sleeping longer was also associated with a decreased use of alcohol, cigarettes, and other substances.

This research buttresses the conclusion of the American Academy of Pediatrics, which recommends that all high schools start no earlier than 8:30 a.m. Today, fewer than 15 percent of U.S. high schools comply with the recommendation. If schools can improve adolescents’ sleep by delaying their start times, the researchers believe that teens will go through high school with better overall mental health and less substance use, which will benefit not only their school experience and but also set them up for success in their adult lives.

The study was published in the July issue of Sleep Health.

Beyond the Salt Shaker: Reducing Sodium


Yes, we all know that most Americans consume too much sodium. But a recent study conducted in three areas of the U.S. by researchers at the University of Minnesota found that the salt we add to the foods we prepare at home isn’t why 85 percent of Americans are exceeding the recommended daily limit of 2,300 mg per day. Rather, it’s the commercially prepared foods, including restaurant meals and prepackaged foods, that are increasing our risk for high blood pressure and strokes.

While only 11 percent of our daily sodium intake comes from the kitchen salt shaker, Lisa Harnack, a professor at the School of Public health and the study’s lead author, says that 71 percent comes from commercially prepared foods (14 percent comes from natural sources, such as milk).

Harnack says the findings reinforce the need for the food industry to reduce the amount of sodium in its products. In addition, the study is another reminder for consumers to understand that when it comes to lowering sodium in our diets, focusing on what we eat at restaurants and purchase from the grab-and-go convenience aisles is the most effective strategy. Requesting sodium content information for menu items can also help consumers make more informed choices.

The study was published in the May issue of the American Heart Association journal Circulation.

Neuroscience and the Courtroom


It’s a classic courtroom scenario: A defendant is presented with evidence and answers that it’s all news to her. Whether she’s telling the truth or lying is up to lawyers to prove and a jury to decide.

A technology called Electroencephalography Memory Recognition (EEG), which uses a sensor-fitted skull cap to track activity in memory hotspots in the brain to determine if a subject recognizes a given image or word, may be able to improve the justice system by sorting out the factual from the phony.

Now, a University of Minnesota study led by law professor Francis Shen has found that jurors can incorporate this new type of evidence into their evaluations of criminal defendants, but not be so wowed by the technology that the neuroscientific evidence outweighs the overall strength of the case.

Shen and his research team at the Shen Neurolaw Lab, which explores the legal implications of neuroscience, asked online participants to read two fictional vignettes describing a person accused of a crime. By manipulating expert evidence and the strength of the non-neuroscientific facts against the defendant, they discovered that the neuroscientific evidence was seen as one factor in a host of evidence that determines guilt or innocence.

The paper was published in August in the Journal of Law and the Biosciences.


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