Speaker 1: Welcome to How Stuff Works Now. I'm your host, Lauren Vogelbaum,
Speaker 1: a researcher and writer. Here at How Stuff Works eight
Speaker 1: every week, I'm bringing you three stories from our team
Speaker 1: about the weird and wondrous advances we've seen in science, technology,
Speaker 1: and culture. This week, pregnancy brain is real and researchers
Speaker 1: think they know how and why it works. Unrelated science
Speaker 1: has an answer for that ever burning question how long
Speaker 1: should I go before I wash my bath towel? But first,
Speaker 1: a more serious story from our own writer and editor,
Speaker 1: Eve's Jeff Cope. A study into the connections among users
Speaker 1: and victims of guns has demonstrated the gun violence is
Speaker 1: contagious like a disease. Learning more about how this violence
Speaker 1: spreads could lead to innovations in preventing it. There were
Speaker 1: nearly fifty eight thousand incidents of gun violence in the
Speaker 1: United States. The US ranks high list comparing countries rates
Speaker 1: of gun deaths, and many of the most deadly mass
Speaker 1: shootings in the States occurred in the last several years.
Speaker 1: But despite the alarming stats, scientists claim gun violence research
Speaker 1: is under published and underfunded compared with other leading causes
Speaker 1: of death. That's partially due to n r A backed
Speaker 1: legislative restrictions that discourage agencies like the CDC and National
Speaker 1: Institutes of Health from using public funds on gun violence research.
Speaker 1: A new study makes the case for more research by
Speaker 1: showing that gun violence is a public health issue. In
Speaker 1: the study published in JAMA Internal Medicine, researchers from Yale
Speaker 1: and Harvard Universities found that gun violence spreads like a
Speaker 1: contagious disease through social interactions. They examine the pool of
Speaker 1: people arrested from two thousand and six to two thousand
Speaker 1: and fourteen in Chicago, a city whose gun violence rates
Speaker 1: are above the national average. From that population, researchers identified
Speaker 1: cases of death and injury by gunshot. By linking people
Speaker 1: who co offended or were arrested together for the same um,
Speaker 1: the study authors created a social network of over eleven
Speaker 1: thousand episodes of gun violence that affected nearly ten thousand people.
Speaker 1: Think of co offending as a vehicle for the disease,
Speaker 1: like sex are sharing needles in other epidemics. The researchers
Speaker 1: acknowledged that because they use only co offending as a
Speaker 1: social tie without considering relationships like friendship or employment, the
Speaker 1: study is limited. Based on the social contagion model the
Speaker 1: researchers created, sixty three point one percent of the gun
Speaker 1: violence incidents in the network were influenced by infectors, who
Speaker 1: expose others to the risk of being shot. This suggests
Speaker 1: that people are more likely to be shot after associating
Speaker 1: with the shooting victim, especially when the interaction involves an offense,
Speaker 1: and in true contagion fashion, gun violence even has an
Speaker 1: incubation period. On average, the infective subjects of gun violence
Speaker 1: were shot one hundred twenty five days after the infector
Speaker 1: was shot. The authors ruled out homophily the tendency to
Speaker 1: hang out with similar people, as an explanation for the
Speaker 1: close social ties of people affected by gun violence. In
Speaker 1: other words, these shooting patterns didn't occur because the peers
Speaker 1: were already alike, but because one person's behavior rubbed off
Speaker 1: on the other. It may seem obvious that we influence
Speaker 1: the behaviors and opinions of people were close to, but
Speaker 1: efforts system gun violence usually focus on demographics like age, sex,
Speaker 1: and neighborhood, which puts extra pressure on disadvantaged minority communities.
Speaker 1: In the study, a model that combines social contagion and
Speaker 1: demographics performed better at predicting gun violence subjects than the
Speaker 1: separate social contagion and demographics models. Because of this, the
Speaker 1: authors say that law enforcement and health professionals could better
Speaker 1: predict and prevent shootings by considering both factors. This isn't
Speaker 1: the first time people have recognized firearm violence as an epidemic,
Speaker 1: though in the American Medical Association called it a public
Speaker 1: health crisis, and prior research has studied how gun violence
Speaker 1: spreads through social relationships. But as gun related crimes in
Speaker 1: the debay over stricter gun laws continue, any scientific step
Speaker 1: for a better violence for woodsmen is invaluable. Next up,
Speaker 1: staff editor Christopher Hasiotis and our freelance writer Laurie L.
Speaker 1: Dove bring us the story behind pregnancy brain. If you've
Speaker 1: ever known or been a pregnant woman who has become
Speaker 1: a bit more forgetful than usual, there's a reason for that,
Speaker 1: and the effects last longer than we thought. Perhaps you're
Speaker 1: familiar with the so called mom nisia that can occur
Speaker 1: during a pregnancy, not to mention the sweeping hormonal, emotional, chemical,
Speaker 1: and physical changes both external and in But a new
Speaker 1: study published in the journal Natural neuroscience contends the pregnancy
Speaker 1: alters regions of the brain for up to two years
Speaker 1: after a woman gives birth. Why well, the changes serve
Speaker 1: an incredibly useful purpose, aiding a mother's ability to bond
Speaker 1: with and give undivided attention to a newborn and just
Speaker 1: the newborn. So what actually happened to the brain of
Speaker 1: a pregnant mother to be the changes involved the purning
Speaker 1: of the size and structure of certain areas of the
Speaker 1: brain that process social information, such as the feelings and tensions, thoughts,
Speaker 1: or even the beliefs of others. This lets the new
Speaker 1: mom put other things on the back burner to help
Speaker 1: up the odds of the newborn survival. Using magnetic resonance
Speaker 1: imaging or m r I scanning, a team out of
Speaker 1: the Autonomous University of Barcelona in Spain analyzed the brains
Speaker 1: of twenty first time mothers before and after their pregnancies,
Speaker 1: as well as those of nineteen of their male partners.
Speaker 1: The team also looked at a control group of twenty
Speaker 1: women who had never been pregnant, as well as seventeen
Speaker 1: additional male partners. Over a five year period. The researchers
Speaker 1: took m R I scans of the study participants at
Speaker 1: regular intervals, and these scans revealed changes in the pregnant
Speaker 1: women's brains. Specifically, there was a reduction in gray matter
Speaker 1: in the prefrontal and temporal cortexes, which are the areas
Speaker 1: that correspond with social cognition and self focused processing. Interestingly,
Speaker 1: these deficits did not create a cognitive struggle, but actually
Speaker 1: enhance certain functions. The changes to pregnant women's brains as
Speaker 1: shown in the scans were so prevalent and so consistent
Speaker 1: that scientists could tell whether a woman had been pregnant
Speaker 1: before just by looking at a brain scan. Scientists also
Speaker 1: could predict a mother's level of attachment to her newborn
Speaker 1: based on these brain changes and scans. According to the
Speaker 1: studies leads scientist, the findings point to an adaptive process
Speaker 1: related to the benefits of detecting the needs of the child,
Speaker 1: such as identifying the newborn's emotional state. So if a
Speaker 1: new mother in your life seems brusque, distracted, or otherwise
Speaker 1: scatter brained, you've got the trial and error process of
Speaker 1: evolution to think. Finally, this week, senior editor Katherine Whitburn
Speaker 1: and our freelance writer Alia Hoyt delve into some bathroom science.
Speaker 1: We all know that our bath towels have limited lifespans
Speaker 1: between washes. How often is often enough For many people,
Speaker 1: a weekly bath towel change is the norm. After all,
Speaker 1: you're cleaned from your nice, hot shower, so how bad
Speaker 1: could your towel get? Right? Well, although your body is
Speaker 1: feeling delightfully fresh, the average towel collects tens of millions
Speaker 1: of dead skin cells, as well as any fungi or
Speaker 1: bacteria that survived your scrub down. Since your private parts
Speaker 1: also come in contact with your towel, urinary and innal
Speaker 1: secretions are also transferred to it. You worse, most toilets
Speaker 1: aren't all that far away from the shower, and droplets
Speaker 1: of toilet water have been known to reach far and
Speaker 1: wide when flushed, leaving your damp hanging towel at risk.
Speaker 1: Speaking of damp, every moment that a towel is left
Speaker 1: out to dry, it allows germs to multiply unchecked. The
Speaker 1: humid atmosphere that's so common to bathroom areas is perfect
Speaker 1: for encouraging the growth of mildew and other undesirable stuff,
Speaker 1: So don't leave your wet towel on the floor or
Speaker 1: scrunched up on the towel bar, hang it spread out
Speaker 1: so it can dry completely. Speed up the drying cross
Speaker 1: us by opening a window or turning on the bathroom fan.
Speaker 1: And if the tallest starts to smell fonki, that means
Speaker 1: mildew is a thriving and it definitely needs to go
Speaker 1: in the laundry. So because of all those germs, back
Speaker 1: to your and mildew, the experts say you should go
Speaker 1: no more than three uses without washing your bath towel,
Speaker 1: and you should wash it in warm or hot water,
Speaker 1: dechargent and some colors safe leach three times. That's all.
Speaker 1: Who knew that's a show for this week. Thank you
Speaker 1: so much for tuning in, especially Caroline, a fellow huffle puff. Caroline,
Speaker 1: my patronis is apparently a Bassett Hound. Further thanks to
Speaker 1: our audio producer Dylan Fagan and our editorial liaison Alison
Speaker 1: luder Milk. Subscribe to now Now for more of the
Speaker 1: latest science news and send us links to anything you'd
Speaker 1: like to hear his cover plus a comic book, ear
Speaker 1: reading or rereading. I just got into The Walking Dead.
Speaker 1: You can send us an email at now podcast at
Speaker 1: how stuff works dot com, and of course, for lots
Speaker 1: more stories like these, head on over to our home
Speaker 1: planet now dot how stuff works dot com MHM