NPR Shortwave science roundup: quitting smoking and brain health, preterm language development, and a Chicago rat hole mystery

Three science stories from NPR Shortwave examine how everyday actions affect health and development. A Lancet Health Longevity study shows that quitting smoking, even in middle age or later, benefits brain function and may reduce dementia risk, challenging the notion that brain health cannot improve with age. A NICU-focused study examines how reading aloud to preterm babies, using a familiar book like Paddington Bear for long daily sessions, correlates with more mature language-related brain connections, though the cohort was small and follow-up is planned. The episode also recounts a Chicago urban wildlife mystery where researchers demonstrated that a sidewalk rat imprint was actually from a squirrel, illustrating how data, methods, and public engagement drive scientific understanding. The stories highlight real-world impacts, from neonatal care to public science outreach and personal health decisions.

Smoking, memory, and dementia risk

The episode summarizes a Lancet Health Longevity study drawing on survey data from over 9,000 smokers across 12 countries over nearly two decades. Half quit and half continued, with cognitive testing showing that those who quit in middle age or later performed better on cognitive assessments than those who never quit. Researchers explain that quitting can reduce vascular damage in the brain and improve oxygen delivery to neural tissue, potentially delaying cognitive decline. The team notes that while cognitive scores are not a guaranteed predictor of dementia, clinicians view them as meaningful indicators of long-term risk. Dr. Michaela Bloomberg, the study's lead author, frames quitting at any age as beneficial for brain health, aligning with broader findings on heart–brain health connections.

"even quitting later in life, it can help your brain" - Michaela Bloomberg, epidemiologist

Language development in preterm babies and an NICU sound intervention

The second segment looks at how early hearing begins in the womb, with the fetal auditory system becoming functional around 24 weeks. Preterm infants, born before 37 weeks, are at higher risk for later language delays, possibly because their NICU environment lacks the constant language exposure of the womb. Researchers led by Melissa Scala at Stanford explored an intervention: playing recordings of mothers reading Paddington Bear for 160 minutes each night to 46 preterm infants. Compared with a control group, babies in the intervention group showed brain changes in language-associated white matter, suggesting a neurodevelopmental benefit. The study, published in Frontiers in Human Neuroscience, is small and not designed for long-term outcomes, but it has already influenced care at the hospital, which now provides free books and opportunities for parents to record their voices.

"The fetal auditory system actually starts to become functional at 24 weeks" - Melissa Scala, Stanford

Urban animal mystery: a Chicago rat hole turns out to be a squirrel

The final segment recounts a viral Chicago phenomenon—the rat hole imprint in wet cement that drew attention and even a wedding. Zoologist Michael Granitosky and colleagues treated the online curiosity as a research opportunity, collecting public photos and comparing body measurements to specimens in the American Museum of Natural History. Statistical analysis showed the imprint was not from a rat but from a squirrel, offering a playful example of how scientists test hypotheses with public data. The researchers emphasize that this public-facing mystery demonstrates how science is done and can inspire broader engagement with the natural world.

"There is science. There's something to take away here" - Michael Granitosky, zoologist