1
00:00:01,120 --> 00:00:03,960
Speaker 1: Welcome to How Stuff Works Now. I'm your host, Lauren Vogelbaum,

2
00:00:04,000 --> 00:00:08,160
Speaker 1: a researcher and writer. Here at How Stuff Works eight

3
00:00:10,240 --> 00:00:12,760
Speaker 1: every week, I'm bringing you three stories from our team

4
00:00:12,800 --> 00:00:16,440
Speaker 1: about the weird and wondrous advances we've seen in science, technology,

5
00:00:16,480 --> 00:00:20,840
Speaker 1: and culture. This week, pregnancy brain is real and researchers

6
00:00:20,880 --> 00:00:25,160
Speaker 1: think they know how and why it works. Unrelated science

7
00:00:25,160 --> 00:00:28,360
Speaker 1: has an answer for that ever burning question how long

8
00:00:28,400 --> 00:00:32,520
Speaker 1: should I go before I wash my bath towel? But first,

9
00:00:32,920 --> 00:00:35,560
Speaker 1: a more serious story from our own writer and editor,

10
00:00:35,720 --> 00:00:38,839
Speaker 1: Eve's Jeff Cope. A study into the connections among users

11
00:00:38,840 --> 00:00:41,720
Speaker 1: and victims of guns has demonstrated the gun violence is

12
00:00:41,800 --> 00:00:45,440
Speaker 1: contagious like a disease. Learning more about how this violence

13
00:00:45,479 --> 00:00:53,040
Speaker 1: spreads could lead to innovations in preventing it. There were

14
00:00:53,040 --> 00:00:55,920
Speaker 1: nearly fifty eight thousand incidents of gun violence in the

15
00:00:56,000 --> 00:01:00,320
Speaker 1: United States. The US ranks high list comparing countries rates

16
00:01:00,320 --> 00:01:03,160
Speaker 1: of gun deaths, and many of the most deadly mass

17
00:01:03,200 --> 00:01:06,119
Speaker 1: shootings in the States occurred in the last several years.

18
00:01:06,640 --> 00:01:10,400
Speaker 1: But despite the alarming stats, scientists claim gun violence research

19
00:01:10,480 --> 00:01:14,240
Speaker 1: is under published and underfunded compared with other leading causes

20
00:01:14,240 --> 00:01:16,840
Speaker 1: of death. That's partially due to n r A backed

21
00:01:16,920 --> 00:01:21,360
Speaker 1: legislative restrictions that discourage agencies like the CDC and National

22
00:01:21,400 --> 00:01:25,240
Speaker 1: Institutes of Health from using public funds on gun violence research.

23
00:01:26,160 --> 00:01:28,880
Speaker 1: A new study makes the case for more research by

24
00:01:28,880 --> 00:01:31,920
Speaker 1: showing that gun violence is a public health issue. In

25
00:01:31,959 --> 00:01:36,160
Speaker 1: the study published in JAMA Internal Medicine, researchers from Yale

26
00:01:36,160 --> 00:01:39,280
Speaker 1: and Harvard Universities found that gun violence spreads like a

27
00:01:39,280 --> 00:01:43,679
Speaker 1: contagious disease through social interactions. They examine the pool of

28
00:01:43,680 --> 00:01:46,040
Speaker 1: people arrested from two thousand and six to two thousand

29
00:01:46,040 --> 00:01:49,120
Speaker 1: and fourteen in Chicago, a city whose gun violence rates

30
00:01:49,160 --> 00:01:53,760
Speaker 1: are above the national average. From that population, researchers identified

31
00:01:53,760 --> 00:01:57,200
Speaker 1: cases of death and injury by gunshot. By linking people

32
00:01:57,200 --> 00:02:00,640
Speaker 1: who co offended or were arrested together for the same um,

33
00:02:00,680 --> 00:02:03,440
Speaker 1: the study authors created a social network of over eleven

34
00:02:03,440 --> 00:02:07,280
Speaker 1: thousand episodes of gun violence that affected nearly ten thousand people.

35
00:02:08,040 --> 00:02:10,480
Speaker 1: Think of co offending as a vehicle for the disease,

36
00:02:10,960 --> 00:02:14,480
Speaker 1: like sex are sharing needles in other epidemics. The researchers

37
00:02:14,480 --> 00:02:17,080
Speaker 1: acknowledged that because they use only co offending as a

38
00:02:17,120 --> 00:02:21,640
Speaker 1: social tie without considering relationships like friendship or employment, the

39
00:02:21,680 --> 00:02:24,760
Speaker 1: study is limited. Based on the social contagion model the

40
00:02:24,800 --> 00:02:28,280
Speaker 1: researchers created, sixty three point one percent of the gun

41
00:02:28,360 --> 00:02:32,119
Speaker 1: violence incidents in the network were influenced by infectors, who

42
00:02:32,160 --> 00:02:35,480
Speaker 1: expose others to the risk of being shot. This suggests

43
00:02:35,480 --> 00:02:38,280
Speaker 1: that people are more likely to be shot after associating

44
00:02:38,520 --> 00:02:42,120
Speaker 1: with the shooting victim, especially when the interaction involves an offense,

45
00:02:43,240 --> 00:02:46,400
Speaker 1: and in true contagion fashion, gun violence even has an

46
00:02:46,440 --> 00:02:50,519
Speaker 1: incubation period. On average, the infective subjects of gun violence

47
00:02:50,520 --> 00:02:53,079
Speaker 1: were shot one hundred twenty five days after the infector

48
00:02:53,160 --> 00:02:57,160
Speaker 1: was shot. The authors ruled out homophily the tendency to

49
00:02:57,200 --> 00:02:59,960
Speaker 1: hang out with similar people, as an explanation for the

50
00:03:00,040 --> 00:03:03,600
Speaker 1: close social ties of people affected by gun violence. In

51
00:03:03,639 --> 00:03:06,840
Speaker 1: other words, these shooting patterns didn't occur because the peers

52
00:03:06,880 --> 00:03:10,240
Speaker 1: were already alike, but because one person's behavior rubbed off

53
00:03:10,280 --> 00:03:13,560
Speaker 1: on the other. It may seem obvious that we influence

54
00:03:13,600 --> 00:03:16,400
Speaker 1: the behaviors and opinions of people were close to, but

55
00:03:16,480 --> 00:03:20,600
Speaker 1: efforts system gun violence usually focus on demographics like age, sex,

56
00:03:20,639 --> 00:03:25,040
Speaker 1: and neighborhood, which puts extra pressure on disadvantaged minority communities.

57
00:03:25,600 --> 00:03:28,560
Speaker 1: In the study, a model that combines social contagion and

58
00:03:28,600 --> 00:03:32,120
Speaker 1: demographics performed better at predicting gun violence subjects than the

59
00:03:32,200 --> 00:03:36,560
Speaker 1: separate social contagion and demographics models. Because of this, the

60
00:03:36,560 --> 00:03:39,760
Speaker 1: authors say that law enforcement and health professionals could better

61
00:03:39,800 --> 00:03:43,600
Speaker 1: predict and prevent shootings by considering both factors. This isn't

62
00:03:43,600 --> 00:03:47,000
Speaker 1: the first time people have recognized firearm violence as an epidemic,

63
00:03:47,040 --> 00:03:51,440
Speaker 1: though in the American Medical Association called it a public

64
00:03:51,440 --> 00:03:54,640
Speaker 1: health crisis, and prior research has studied how gun violence

65
00:03:54,680 --> 00:03:58,320
Speaker 1: spreads through social relationships. But as gun related crimes in

66
00:03:58,360 --> 00:04:02,000
Speaker 1: the debay over stricter gun laws continue, any scientific step

67
00:04:02,080 --> 00:04:10,920
Speaker 1: for a better violence for woodsmen is invaluable. Next up,

68
00:04:11,000 --> 00:04:14,360
Speaker 1: staff editor Christopher Hasiotis and our freelance writer Laurie L.

69
00:04:14,440 --> 00:04:17,960
Speaker 1: Dove bring us the story behind pregnancy brain. If you've

70
00:04:17,960 --> 00:04:20,440
Speaker 1: ever known or been a pregnant woman who has become

71
00:04:20,480 --> 00:04:23,520
Speaker 1: a bit more forgetful than usual, there's a reason for that,

72
00:04:23,880 --> 00:04:30,200
Speaker 1: and the effects last longer than we thought. Perhaps you're

73
00:04:30,240 --> 00:04:33,279
Speaker 1: familiar with the so called mom nisia that can occur

74
00:04:33,360 --> 00:04:37,360
Speaker 1: during a pregnancy, not to mention the sweeping hormonal, emotional, chemical,

75
00:04:37,400 --> 00:04:40,800
Speaker 1: and physical changes both external and in But a new

76
00:04:40,839 --> 00:04:44,479
Speaker 1: study published in the journal Natural neuroscience contends the pregnancy

77
00:04:44,520 --> 00:04:47,120
Speaker 1: alters regions of the brain for up to two years

78
00:04:47,200 --> 00:04:51,240
Speaker 1: after a woman gives birth. Why well, the changes serve

79
00:04:51,279 --> 00:04:54,599
Speaker 1: an incredibly useful purpose, aiding a mother's ability to bond

80
00:04:54,600 --> 00:04:57,640
Speaker 1: with and give undivided attention to a newborn and just

81
00:04:57,839 --> 00:05:00,640
Speaker 1: the newborn. So what actually happened to the brain of

82
00:05:00,640 --> 00:05:03,599
Speaker 1: a pregnant mother to be the changes involved the purning

83
00:05:03,600 --> 00:05:05,760
Speaker 1: of the size and structure of certain areas of the

84
00:05:05,800 --> 00:05:10,440
Speaker 1: brain that process social information, such as the feelings and tensions, thoughts,

85
00:05:10,560 --> 00:05:13,240
Speaker 1: or even the beliefs of others. This lets the new

86
00:05:13,279 --> 00:05:15,480
Speaker 1: mom put other things on the back burner to help

87
00:05:15,560 --> 00:05:19,000
Speaker 1: up the odds of the newborn survival. Using magnetic resonance

88
00:05:19,040 --> 00:05:21,359
Speaker 1: imaging or m r I scanning, a team out of

89
00:05:21,360 --> 00:05:25,320
Speaker 1: the Autonomous University of Barcelona in Spain analyzed the brains

90
00:05:25,320 --> 00:05:29,000
Speaker 1: of twenty first time mothers before and after their pregnancies,

91
00:05:29,320 --> 00:05:31,680
Speaker 1: as well as those of nineteen of their male partners.

92
00:05:32,480 --> 00:05:34,599
Speaker 1: The team also looked at a control group of twenty

93
00:05:34,600 --> 00:05:37,200
Speaker 1: women who had never been pregnant, as well as seventeen

94
00:05:37,240 --> 00:05:40,880
Speaker 1: additional male partners. Over a five year period. The researchers

95
00:05:40,880 --> 00:05:43,200
Speaker 1: took m R I scans of the study participants at

96
00:05:43,279 --> 00:05:46,640
Speaker 1: regular intervals, and these scans revealed changes in the pregnant

97
00:05:46,680 --> 00:05:50,400
Speaker 1: women's brains. Specifically, there was a reduction in gray matter

98
00:05:50,440 --> 00:05:53,800
Speaker 1: in the prefrontal and temporal cortexes, which are the areas

99
00:05:53,800 --> 00:05:58,240
Speaker 1: that correspond with social cognition and self focused processing. Interestingly,

100
00:05:58,680 --> 00:06:01,920
Speaker 1: these deficits did not create a cognitive struggle, but actually

101
00:06:02,000 --> 00:06:05,600
Speaker 1: enhance certain functions. The changes to pregnant women's brains as

102
00:06:05,640 --> 00:06:08,320
Speaker 1: shown in the scans were so prevalent and so consistent

103
00:06:08,600 --> 00:06:10,800
Speaker 1: that scientists could tell whether a woman had been pregnant

104
00:06:10,839 --> 00:06:14,279
Speaker 1: before just by looking at a brain scan. Scientists also

105
00:06:14,279 --> 00:06:16,719
Speaker 1: could predict a mother's level of attachment to her newborn

106
00:06:17,040 --> 00:06:20,280
Speaker 1: based on these brain changes and scans. According to the

107
00:06:20,279 --> 00:06:23,880
Speaker 1: studies leads scientist, the findings point to an adaptive process

108
00:06:23,920 --> 00:06:26,480
Speaker 1: related to the benefits of detecting the needs of the child,

109
00:06:26,880 --> 00:06:30,120
Speaker 1: such as identifying the newborn's emotional state. So if a

110
00:06:30,160 --> 00:06:33,320
Speaker 1: new mother in your life seems brusque, distracted, or otherwise

111
00:06:33,360 --> 00:06:35,839
Speaker 1: scatter brained, you've got the trial and error process of

112
00:06:35,839 --> 00:06:46,120
Speaker 1: evolution to think. Finally, this week, senior editor Katherine Whitburn

113
00:06:46,240 --> 00:06:49,960
Speaker 1: and our freelance writer Alia Hoyt delve into some bathroom science.

114
00:06:50,320 --> 00:06:53,200
Speaker 1: We all know that our bath towels have limited lifespans

115
00:06:53,240 --> 00:07:02,240
Speaker 1: between washes. How often is often enough For many people,

116
00:07:02,360 --> 00:07:05,360
Speaker 1: a weekly bath towel change is the norm. After all,

117
00:07:05,560 --> 00:07:07,839
Speaker 1: you're cleaned from your nice, hot shower, so how bad

118
00:07:07,839 --> 00:07:10,760
Speaker 1: could your towel get? Right? Well, although your body is

119
00:07:10,760 --> 00:07:14,520
Speaker 1: feeling delightfully fresh, the average towel collects tens of millions

120
00:07:14,560 --> 00:07:17,680
Speaker 1: of dead skin cells, as well as any fungi or

121
00:07:17,720 --> 00:07:21,400
Speaker 1: bacteria that survived your scrub down. Since your private parts

122
00:07:21,440 --> 00:07:24,520
Speaker 1: also come in contact with your towel, urinary and innal

123
00:07:24,640 --> 00:07:29,760
Speaker 1: secretions are also transferred to it. You worse, most toilets

124
00:07:29,760 --> 00:07:32,480
Speaker 1: aren't all that far away from the shower, and droplets

125
00:07:32,480 --> 00:07:34,600
Speaker 1: of toilet water have been known to reach far and

126
00:07:34,640 --> 00:07:38,440
Speaker 1: wide when flushed, leaving your damp hanging towel at risk.

127
00:07:39,040 --> 00:07:41,800
Speaker 1: Speaking of damp, every moment that a towel is left

128
00:07:41,800 --> 00:07:45,360
Speaker 1: out to dry, it allows germs to multiply unchecked. The

129
00:07:45,440 --> 00:07:48,440
Speaker 1: humid atmosphere that's so common to bathroom areas is perfect

130
00:07:48,520 --> 00:07:51,880
Speaker 1: for encouraging the growth of mildew and other undesirable stuff,

131
00:07:52,360 --> 00:07:54,440
Speaker 1: So don't leave your wet towel on the floor or

132
00:07:54,480 --> 00:07:57,080
Speaker 1: scrunched up on the towel bar, hang it spread out

133
00:07:57,120 --> 00:07:59,960
Speaker 1: so it can dry completely. Speed up the drying cross

134
00:08:00,080 --> 00:08:03,160
Speaker 1: us by opening a window or turning on the bathroom fan.

135
00:08:03,760 --> 00:08:06,240
Speaker 1: And if the tallest starts to smell fonki, that means

136
00:08:06,280 --> 00:08:08,720
Speaker 1: mildew is a thriving and it definitely needs to go

137
00:08:08,760 --> 00:08:11,480
Speaker 1: in the laundry. So because of all those germs, back

138
00:08:11,520 --> 00:08:14,000
Speaker 1: to your and mildew, the experts say you should go

139
00:08:14,160 --> 00:08:17,560
Speaker 1: no more than three uses without washing your bath towel,

140
00:08:18,040 --> 00:08:20,240
Speaker 1: and you should wash it in warm or hot water,

141
00:08:20,480 --> 00:08:24,560
Speaker 1: dechargent and some colors safe leach three times. That's all.

142
00:08:25,040 --> 00:08:31,480
Speaker 1: Who knew that's a show for this week. Thank you

143
00:08:31,640 --> 00:08:35,840
Speaker 1: so much for tuning in, especially Caroline, a fellow huffle puff. Caroline,

144
00:08:35,960 --> 00:08:39,360
Speaker 1: my patronis is apparently a Bassett Hound. Further thanks to

145
00:08:39,360 --> 00:08:42,600
Speaker 1: our audio producer Dylan Fagan and our editorial liaison Alison

146
00:08:42,679 --> 00:08:45,520
Speaker 1: luder Milk. Subscribe to now Now for more of the

147
00:08:45,600 --> 00:08:48,000
Speaker 1: latest science news and send us links to anything you'd

148
00:08:48,000 --> 00:08:50,480
Speaker 1: like to hear his cover plus a comic book, ear

149
00:08:50,520 --> 00:08:53,440
Speaker 1: reading or rereading. I just got into The Walking Dead.

150
00:08:53,920 --> 00:08:56,200
Speaker 1: You can send us an email at now podcast at

151
00:08:56,240 --> 00:08:59,280
Speaker 1: how stuff works dot com, and of course, for lots

152
00:08:59,320 --> 00:09:01,640
Speaker 1: more stories like these, head on over to our home

153
00:09:01,720 --> 00:09:08,520
Speaker 1: planet now dot how stuff works dot com MHM