By Lydielyle Gibson and Jason Kelly
Photography courtesy NASA/Jet Propulsion Laboratory

Accidents happen
Young children apprehend the difference between intentional and inadvertent damage, but it’s not until they’re adults that they begin to see breaking something by accident as a less punishable offense than deliberate harm. As people age, their moral reasoning matures, along with their ability to understand others’ mental states. In a study in the June Cerebral Cortex, neuroscientist Jean Decety analyzed fMRI results of 127 participants between 4 and 36 years old as they watched video clips of someone being shoved or accidentally struck, a bicycle tire being kicked or a teapot being knocked off a shelf by mistake. Looking at brain scans, eye tracking, and behavior, Decety found that the amygdala, the brain region associated with emotional response, was more activated in children than adults; for adults, brain activity was highest in prefrontal-cortex areas involved in decision making and evaluation. Adults were also less likely to say that accidental damage deserved punishment.

Fecal matter
More than 1,000 strains of bacteria interact in a healthy bowel, and when antibiotics or disease disrupt that balance, it can lead to severe diarrhea, inflammation, tissue damage, and even death. An experimental therapy shows promise, if people can get past the “yuck factor.” The treatment: fecal microbiota transplantation—collecting a stool sample from a healthy person and injecting it into the patient’s colon to reestablish bacterial balance. Gastroenterologist David Rubin and Medical Center colleagues Stacy Kahn and Rita Gorawara-Bhat, PhD’93, studied the social and ethical implications in focus groups with colitis patients. In the July Inflammatory Bowel Diseases they reported that patients were eager to try the treatment and considered it more “natural” than other therapies. The Medical Center hopes to begin offering a clinical trial this fall. The researchers’ concern was donor selection: as with organ transplants, the physicians recommend screening donors for HIV, hepatitis, and other pathogens, as well as for diet and medications that could affect the patients.

Harder than 1, 2, 3
Preschoolers don’t learn to count unless they’re taught numbers higher than three. Studying children’s ability to understand the connection between number words and their numeric value, psychology professor Susan Levine and PhD student Elizabeth Gunderson found that children whose parents exposed them to the numbers four through ten—both words and objects—grasped the concept of counting faster than children who learned only one through three. Recognizing groups of three, hypothesized Levine, who also codirects Chicago’s Center for Early Childhood Development, doesn’t require actual counting. For the study, researchers videotaped interactions between parents and 44 kids between 14 and 30 months. The results were published in the June Developmental Science.

Mars formed fast, but it stayed small.
Mars formed fast, but it stayed small.

Red embryo
It took Earth 50 to 100 million years and numerous collisions with smaller celestial bodies to reach its current size. By contrast, says cosmochemist Nicholas Dauphas, Mars finished growing two to four million years after the solar system was born. And that rapid formation may have stunted its size. Calling Mars a “planetary embryo” that never collided with other embryos to form a terrestrial planet like Earth, Dauphas and coauthor Ali Pourmand offered evidence in the May 26 Nature that clears up some longstanding uncertainties about the red planet’s history and development. The researchers refined the planet’s age using computer simulations and comparative analyses of certain elements in martian meteorites and in other meteorites called chondrites, debris that remains basically unchanged since the beginning of the solar system.


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