1 00:00:02,040 --> 00:00:07,120 Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, 2 00:00:07,120 --> 00:00:09,960 Speaker 1: I'm Lauren voc Obam, and today's episode is another brain 3 00:00:10,039 --> 00:00:13,680 Speaker 1: Stuff classic from our erstwhile host, Christian Sager. Our question 4 00:00:13,720 --> 00:00:16,319 Speaker 1: for the day, why do men tend to have deeper 5 00:00:16,440 --> 00:00:23,680 Speaker 1: voices than women? Hello, brain Stuff, I'm Christian Saga, and 6 00:00:23,800 --> 00:00:26,920 Speaker 1: today we're going to talk about the human voice. You 7 00:00:27,000 --> 00:00:29,280 Speaker 1: might have noticed that if you're talking to a group 8 00:00:29,280 --> 00:00:32,080 Speaker 1: of five year old boys and girls, let's say you're 9 00:00:32,120 --> 00:00:35,640 Speaker 1: asking them for advice about your investment portfolio, there's not 10 00:00:35,800 --> 00:00:38,839 Speaker 1: a big difference between the pitch of the girl's voices 11 00:00:38,920 --> 00:00:42,000 Speaker 1: and the pitch of the boys voices. Yet if you 12 00:00:42,120 --> 00:00:44,640 Speaker 1: talk to a group of thirty five year old men 13 00:00:44,680 --> 00:00:47,839 Speaker 1: and women, you notice that the men's voices are on 14 00:00:48,200 --> 00:00:51,800 Speaker 1: average a good bit deeper than the women's voices. So 15 00:00:51,960 --> 00:00:54,959 Speaker 1: why is that and how does it happen? Well, first off, 16 00:00:55,040 --> 00:00:59,000 Speaker 1: let's acknowledge that everyone is a special and unique butterfly, 17 00:00:59,400 --> 00:01:02,040 Speaker 1: and there's no rule about how men and women's voices 18 00:01:02,080 --> 00:01:06,960 Speaker 1: should sound. But on average, adult men's voices have what's 19 00:01:07,000 --> 00:01:12,080 Speaker 1: known as a lower fundamental frequency than adult women's voices. 20 00:01:12,400 --> 00:01:16,400 Speaker 1: The fundamental frequency is simply the scientific term for how 21 00:01:16,480 --> 00:01:21,000 Speaker 1: high or low a person's natural speaking voice sounds. Sound 22 00:01:21,000 --> 00:01:24,080 Speaker 1: frequency is measured in hurts, which is a measure of 23 00:01:24,120 --> 00:01:27,679 Speaker 1: how many times something happens in a second. So a 24 00:01:27,800 --> 00:01:31,000 Speaker 1: sound wave that vibrates a hundred times per second produces 25 00:01:31,040 --> 00:01:34,360 Speaker 1: a tone of a hundred hurts. The more cycles per second, 26 00:01:34,520 --> 00:01:37,440 Speaker 1: the higher the pitch. According to the National Center for 27 00:01:37,600 --> 00:01:41,280 Speaker 1: Voice and Speech, babies usually cry at a frequency of 28 00:01:41,319 --> 00:01:45,720 Speaker 1: around five hundred hurts. Children have speaking frequencies in the 29 00:01:45,840 --> 00:01:48,680 Speaker 1: range of two hundred and fifty to four hundred hurts 30 00:01:48,680 --> 00:01:52,280 Speaker 1: by the time of adulthood. However, men have an average 31 00:01:52,360 --> 00:01:56,640 Speaker 1: fundamental frequency of about one hundred and twenty five hurts 32 00:01:56,640 --> 00:02:00,120 Speaker 1: and women about two hundred hurts. What happened here? What? 33 00:02:00,360 --> 00:02:04,200 Speaker 1: Why the big difference? Okay, to understand why men's voices 34 00:02:04,320 --> 00:02:06,680 Speaker 1: end up lower than women's voices, we need to look 35 00:02:06,720 --> 00:02:09,520 Speaker 1: at how the body produces sounds. So let's take a 36 00:02:09,600 --> 00:02:13,480 Speaker 1: magical journey to the inside of your neck. Leading from 37 00:02:13,520 --> 00:02:16,000 Speaker 1: your lungs to the cavity behind your mouth and nose 38 00:02:16,120 --> 00:02:18,800 Speaker 1: is a pipeline called the tray chia. You use it 39 00:02:18,840 --> 00:02:21,120 Speaker 1: to breathe. At the top of the trachea is a 40 00:02:21,160 --> 00:02:24,680 Speaker 1: hollow organ called the larynx, or in common parlance, the 41 00:02:24,800 --> 00:02:28,440 Speaker 1: voice box. The larynx is amazing. For example, when you 42 00:02:28,480 --> 00:02:31,200 Speaker 1: swallow food, it is a part of the larynx called 43 00:02:31,200 --> 00:02:34,560 Speaker 1: the epiglottis that closes off your tray chia and keeps 44 00:02:34,560 --> 00:02:37,880 Speaker 1: you from getting gummy bears in your lungs. The larynx 45 00:02:37,960 --> 00:02:40,720 Speaker 1: is also what allows us to make sound for talking 46 00:02:40,840 --> 00:02:43,160 Speaker 1: or singing. To do this, you use your lungs to 47 00:02:43,200 --> 00:02:45,760 Speaker 1: push a column of air through the larynx while using 48 00:02:45,760 --> 00:02:49,640 Speaker 1: your laryngeal muscles to press together a pair of membranes 49 00:02:49,720 --> 00:02:54,239 Speaker 1: called the vocal folds, or more commonly, your vocal chords. 50 00:02:54,639 --> 00:02:57,480 Speaker 1: When you close the vocal folds like this, the air 51 00:02:57,560 --> 00:03:01,639 Speaker 1: you push out through them makes them vibrate, and this 52 00:03:01,760 --> 00:03:05,200 Speaker 1: vibration leads to sound. So the next time you're just 53 00:03:05,280 --> 00:03:09,240 Speaker 1: shrieking and shrieking until the cashier finally accepts your expired coupon, 54 00:03:09,760 --> 00:03:13,280 Speaker 1: thank your larynx. There are several factors that can all 55 00:03:13,320 --> 00:03:16,919 Speaker 1: have some effect on the fundamental frequency of a person's voice, 56 00:03:17,000 --> 00:03:20,280 Speaker 1: like the size of the larynx and the differential development 57 00:03:20,320 --> 00:03:24,359 Speaker 1: of facial bones and muscles. But the most important factor 58 00:03:24,400 --> 00:03:27,440 Speaker 1: to talk about is the length of the vocal folds. 59 00:03:27,840 --> 00:03:30,519 Speaker 1: If you pluck a string, the length of the string 60 00:03:30,600 --> 00:03:33,880 Speaker 1: affects the frequency of the note that plays. Think about 61 00:03:33,880 --> 00:03:36,520 Speaker 1: a guitar. When you press a string down to a 62 00:03:36,600 --> 00:03:39,400 Speaker 1: higher fret. On a guitar, you shorten the length of 63 00:03:39,440 --> 00:03:41,880 Speaker 1: the part of the string that vibrates when you pluck it, 64 00:03:42,240 --> 00:03:45,600 Speaker 1: and this produces a higher note. The same thing happens 65 00:03:45,640 --> 00:03:48,920 Speaker 1: inside your larynx. The longer the vocal fold, the lower 66 00:03:48,960 --> 00:03:52,920 Speaker 1: the note. During puberty, both boys and girls experience growth 67 00:03:53,040 --> 00:03:56,320 Speaker 1: of the vocal folds, leading to lower voices, but the 68 00:03:56,360 --> 00:04:01,640 Speaker 1: male hormone testosserone, which is released by the testicles during puberty, 69 00:04:01,760 --> 00:04:06,160 Speaker 1: typically causes boys vocal folds to grow longer and thicker 70 00:04:06,200 --> 00:04:10,000 Speaker 1: than girls. On average, adult women have vocal folds somewhere 71 00:04:10,040 --> 00:04:13,600 Speaker 1: around ten millimeters long, while adult men have vocal folds 72 00:04:13,600 --> 00:04:18,320 Speaker 1: in the neighborhood of sixteen millimeters. Consequently, women are up 73 00:04:18,360 --> 00:04:21,680 Speaker 1: there on the upper frets, soloing into oblivion like a 74 00:04:21,720 --> 00:04:24,560 Speaker 1: high school kid who just learned how to play eruption 75 00:04:24,640 --> 00:04:28,000 Speaker 1: by Van Halen, and men are letting the open strings 76 00:04:28,080 --> 00:04:31,920 Speaker 1: ring like the intro of nothing else matters by Metallica. 77 00:04:32,279 --> 00:04:35,279 Speaker 1: Now here's some bonus information for you. Everyone knows what 78 00:04:35,400 --> 00:04:38,360 Speaker 1: happens when you inhale some helium from a party balloon 79 00:04:38,480 --> 00:04:41,520 Speaker 1: or you know, straight from an industrial helium transport truck. 80 00:04:42,000 --> 00:04:45,680 Speaker 1: Your voice pitch gets higher. This is because helium is 81 00:04:45,800 --> 00:04:48,560 Speaker 1: less dense than air. But did you know you can 82 00:04:48,600 --> 00:04:52,320 Speaker 1: reverse the effect and give yourself a deep, booming bridge 83 00:04:52,360 --> 00:04:55,880 Speaker 1: troll voice by breathing a gas with a higher density 84 00:04:55,920 --> 00:05:00,479 Speaker 1: than your air, like zenon or sulfur hexafloor a ride. 85 00:05:00,720 --> 00:05:03,640 Speaker 1: But remember, your body needs air to live, and breathing 86 00:05:03,640 --> 00:05:06,640 Speaker 1: anything other than air can be dangerous, so don't try 87 00:05:06,680 --> 00:05:13,440 Speaker 1: this at home. Today's episodes written by Joe McCormick and 88 00:05:13,440 --> 00:05:16,040 Speaker 1: produced by Tyler Clang. If you miss Christian you can 89 00:05:16,080 --> 00:05:19,080 Speaker 1: find him on his new pop culture podcast super Context, 90 00:05:19,360 --> 00:05:21,560 Speaker 1: And of course, for more on this and lots of 91 00:05:21,560 --> 00:05:24,599 Speaker 1: other deep topics, visit our home planet, how Stuff Works 92 00:05:24,680 --> 00:05:36,360 Speaker 1: dot com.