WEBVTT - Gun Violence Contagion, Pregnancy Brain, and Dirty Towels

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<v Speaker 1>Welcome to How Stuff Works Now. I'm your host, Lauren Vogelbaum,

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<v Speaker 1>a researcher and writer. Here at How Stuff Works eight

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<v Speaker 1>every week, I'm bringing you three stories from our team

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<v Speaker 1>about the weird and wondrous advances we've seen in science, technology,

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<v Speaker 1>and culture. This week, pregnancy brain is real and researchers

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<v Speaker 1>think they know how and why it works. Unrelated science

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<v Speaker 1>has an answer for that ever burning question how long

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<v Speaker 1>should I go before I wash my bath towel? But first,

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<v Speaker 1>a more serious story from our own writer and editor,

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<v Speaker 1>Eve's Jeff Cope. A study into the connections among users

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<v Speaker 1>and victims of guns has demonstrated the gun violence is

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<v Speaker 1>contagious like a disease. Learning more about how this violence

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<v Speaker 1>spreads could lead to innovations in preventing it. There were

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<v Speaker 1>nearly fifty eight thousand incidents of gun violence in the

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<v Speaker 1>United States. The US ranks high list comparing countries rates

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<v Speaker 1>of gun deaths, and many of the most deadly mass

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<v Speaker 1>shootings in the States occurred in the last several years.

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<v Speaker 1>But despite the alarming stats, scientists claim gun violence research

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<v Speaker 1>is under published and underfunded compared with other leading causes

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<v Speaker 1>of death. That's partially due to n r A backed

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<v Speaker 1>legislative restrictions that discourage agencies like the CDC and National

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<v Speaker 1>Institutes of Health from using public funds on gun violence research.

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<v Speaker 1>A new study makes the case for more research by

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<v Speaker 1>showing that gun violence is a public health issue. In

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<v Speaker 1>the study published in JAMA Internal Medicine, researchers from Yale

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<v Speaker 1>and Harvard Universities found that gun violence spreads like a

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<v Speaker 1>contagious disease through social interactions. They examine the pool of

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<v Speaker 1>people arrested from two thousand and six to two thousand

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<v Speaker 1>and fourteen in Chicago, a city whose gun violence rates

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<v Speaker 1>are above the national average. From that population, researchers identified

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<v Speaker 1>cases of death and injury by gunshot. By linking people

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<v Speaker 1>who co offended or were arrested together for the same um,

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<v Speaker 1>the study authors created a social network of over eleven

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<v Speaker 1>thousand episodes of gun violence that affected nearly ten thousand people.

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<v Speaker 1>Think of co offending as a vehicle for the disease,

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<v Speaker 1>like sex are sharing needles in other epidemics. The researchers

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<v Speaker 1>acknowledged that because they use only co offending as a

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<v Speaker 1>social tie without considering relationships like friendship or employment, the

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<v Speaker 1>study is limited. Based on the social contagion model the

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<v Speaker 1>researchers created, sixty three point one percent of the gun

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<v Speaker 1>violence incidents in the network were influenced by infectors, who

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<v Speaker 1>expose others to the risk of being shot. This suggests

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<v Speaker 1>that people are more likely to be shot after associating

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<v Speaker 1>with the shooting victim, especially when the interaction involves an offense,

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<v Speaker 1>and in true contagion fashion, gun violence even has an

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<v Speaker 1>incubation period. On average, the infective subjects of gun violence

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<v Speaker 1>were shot one hundred twenty five days after the infector

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<v Speaker 1>was shot. The authors ruled out homophily the tendency to

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<v Speaker 1>hang out with similar people, as an explanation for the

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<v Speaker 1>close social ties of people affected by gun violence. In

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<v Speaker 1>other words, these shooting patterns didn't occur because the peers

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<v Speaker 1>were already alike, but because one person's behavior rubbed off

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<v Speaker 1>on the other. It may seem obvious that we influence

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<v Speaker 1>the behaviors and opinions of people were close to, but

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<v Speaker 1>efforts system gun violence usually focus on demographics like age, sex,

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<v Speaker 1>and neighborhood, which puts extra pressure on disadvantaged minority communities.

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<v Speaker 1>In the study, a model that combines social contagion and

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<v Speaker 1>demographics performed better at predicting gun violence subjects than the

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<v Speaker 1>separate social contagion and demographics models. Because of this, the

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<v Speaker 1>authors say that law enforcement and health professionals could better

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<v Speaker 1>predict and prevent shootings by considering both factors. This isn't

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<v Speaker 1>the first time people have recognized firearm violence as an epidemic,

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<v Speaker 1>though in the American Medical Association called it a public

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<v Speaker 1>health crisis, and prior research has studied how gun violence

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<v Speaker 1>spreads through social relationships. But as gun related crimes in

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<v Speaker 1>the debay over stricter gun laws continue, any scientific step

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<v Speaker 1>for a better violence for woodsmen is invaluable. Next up,

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<v Speaker 1>staff editor Christopher Hasiotis and our freelance writer Laurie L.

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<v Speaker 1>Dove bring us the story behind pregnancy brain. If you've

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<v Speaker 1>ever known or been a pregnant woman who has become

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<v Speaker 1>a bit more forgetful than usual, there's a reason for that,

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<v Speaker 1>and the effects last longer than we thought. Perhaps you're

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<v Speaker 1>familiar with the so called mom nisia that can occur

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<v Speaker 1>during a pregnancy, not to mention the sweeping hormonal, emotional, chemical,

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<v Speaker 1>and physical changes both external and in But a new

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<v Speaker 1>study published in the journal Natural neuroscience contends the pregnancy

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<v Speaker 1>alters regions of the brain for up to two years

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<v Speaker 1>after a woman gives birth. Why well, the changes serve

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<v Speaker 1>an incredibly useful purpose, aiding a mother's ability to bond

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<v Speaker 1>with and give undivided attention to a newborn and just

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<v Speaker 1>the newborn. So what actually happened to the brain of

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<v Speaker 1>a pregnant mother to be the changes involved the purning

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<v Speaker 1>of the size and structure of certain areas of the

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<v Speaker 1>brain that process social information, such as the feelings and tensions, thoughts,

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<v Speaker 1>or even the beliefs of others. This lets the new

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<v Speaker 1>mom put other things on the back burner to help

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<v Speaker 1>up the odds of the newborn survival. Using magnetic resonance

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<v Speaker 1>imaging or m r I scanning, a team out of

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<v Speaker 1>the Autonomous University of Barcelona in Spain analyzed the brains

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<v Speaker 1>of twenty first time mothers before and after their pregnancies,

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<v Speaker 1>as well as those of nineteen of their male partners.

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<v Speaker 1>The team also looked at a control group of twenty

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<v Speaker 1>women who had never been pregnant, as well as seventeen

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<v Speaker 1>additional male partners. Over a five year period. The researchers

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<v Speaker 1>took m R I scans of the study participants at

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<v Speaker 1>regular intervals, and these scans revealed changes in the pregnant

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<v Speaker 1>women's brains. Specifically, there was a reduction in gray matter

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<v Speaker 1>in the prefrontal and temporal cortexes, which are the areas

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<v Speaker 1>that correspond with social cognition and self focused processing. Interestingly,

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<v Speaker 1>these deficits did not create a cognitive struggle, but actually

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<v Speaker 1>enhance certain functions. The changes to pregnant women's brains as

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<v Speaker 1>shown in the scans were so prevalent and so consistent

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<v Speaker 1>that scientists could tell whether a woman had been pregnant

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<v Speaker 1>before just by looking at a brain scan. Scientists also

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<v Speaker 1>could predict a mother's level of attachment to her newborn

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<v Speaker 1>based on these brain changes and scans. According to the

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<v Speaker 1>studies leads scientist, the findings point to an adaptive process

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<v Speaker 1>related to the benefits of detecting the needs of the child,

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<v Speaker 1>such as identifying the newborn's emotional state. So if a

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<v Speaker 1>new mother in your life seems brusque, distracted, or otherwise

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<v Speaker 1>scatter brained, you've got the trial and error process of

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<v Speaker 1>evolution to think. Finally, this week, senior editor Katherine Whitburn

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<v Speaker 1>and our freelance writer Alia Hoyt delve into some bathroom science.

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<v Speaker 1>We all know that our bath towels have limited lifespans

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<v Speaker 1>between washes. How often is often enough For many people,

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<v Speaker 1>a weekly bath towel change is the norm. After all,

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<v Speaker 1>you're cleaned from your nice, hot shower, so how bad

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<v Speaker 1>could your towel get? Right? Well, although your body is

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<v Speaker 1>feeling delightfully fresh, the average towel collects tens of millions

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<v Speaker 1>of dead skin cells, as well as any fungi or

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<v Speaker 1>bacteria that survived your scrub down. Since your private parts

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<v Speaker 1>also come in contact with your towel, urinary and innal

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<v Speaker 1>secretions are also transferred to it. You worse, most toilets

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<v Speaker 1>aren't all that far away from the shower, and droplets

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<v Speaker 1>of toilet water have been known to reach far and

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<v Speaker 1>wide when flushed, leaving your damp hanging towel at risk.

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<v Speaker 1>Speaking of damp, every moment that a towel is left

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<v Speaker 1>out to dry, it allows germs to multiply unchecked. The

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<v Speaker 1>humid atmosphere that's so common to bathroom areas is perfect

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<v Speaker 1>for encouraging the growth of mildew and other undesirable stuff,

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<v Speaker 1>So don't leave your wet towel on the floor or

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<v Speaker 1>scrunched up on the towel bar, hang it spread out

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<v Speaker 1>so it can dry completely. Speed up the drying cross

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<v Speaker 1>us by opening a window or turning on the bathroom fan.

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<v Speaker 1>And if the tallest starts to smell fonki, that means

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<v Speaker 1>mildew is a thriving and it definitely needs to go

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<v Speaker 1>in the laundry. So because of all those germs, back

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<v Speaker 1>to your and mildew, the experts say you should go

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<v Speaker 1>no more than three uses without washing your bath towel,

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<v Speaker 1>and you should wash it in warm or hot water,

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<v Speaker 1>dechargent and some colors safe leach three times. That's all.

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<v Speaker 1>Who knew that's a show for this week. Thank you

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<v Speaker 1>so much for tuning in, especially Caroline, a fellow huffle puff. Caroline,

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<v Speaker 1>my patronis is apparently a Bassett Hound. Further thanks to

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<v Speaker 1>our audio producer Dylan Fagan and our editorial liaison Alison

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<v Speaker 1>luder Milk. Subscribe to now Now for more of the

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<v Speaker 1>latest science news and send us links to anything you'd

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<v Speaker 1>like to hear his cover plus a comic book, ear

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<v Speaker 1>reading or rereading. I just got into The Walking Dead.

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<v Speaker 1>You can send us an email at now podcast at

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