Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, I'm Lauren voc Obam, and today's episode is another brain Stuff classic from our erstwhile host, Christian Sager. Our question for the day, why do men tend to have deeper voices than women? Hello, brain Stuff, I'm Christian Saga, and
today we're going to talk about the human voice. You might have noticed that if you're talking to a group of five year old boys and girls, let's say you're asking them for advice about your investment portfolio, there's not a big difference between the pitch of the girl's voices and the pitch of the boys voices. Yet if you talk to a group of thirty five year old men and women, you notice that the men's voices are on average a good bit deeper than the women's voices. So
why is that and how does it happen? Well, first off, let's acknowledge that everyone is a special and unique butterfly, and there's no rule about how men and women's voices should sound. But on average, adult men's voices have what's known as a lower fundamental frequency than adult women's voices. The fundamental frequency is simply the scientific term for how high or low a person's natural speaking voice sounds. Sound frequency is measured in hurts, which is a measure of
how many times something happens in a second. So a sound wave that vibrates a hundred times per second produces a tone of a hundred hurts. The more cycles per second, the higher the pitch. According to the National Center for Voice and Speech, babies usually cry at a frequency of around five hundred hurts. Children have speaking frequencies in the range of two hundred and fifty to four hundred hurts
by the time of adulthood. However, men have an average fundamental frequency of about one hundred and twenty five hurts and women about two hundred hurts. What happened here? What? Why the big difference? Okay, to understand why men's voices end up lower than women's voices, we need to look at how the body produces sounds. So let's take a magical journey to the inside of your neck. Leading from your lungs to the cavity behind your mouth and nose is a pipeline called the tray chia. You use it
to breathe. At the top of the trachea is a hollow organ called the larynx, or in common parlance, the voice box. The larynx is amazing. For example, when you swallow food, it is a part of the larynx called the epiglottis that closes off your tray chia and keeps you from getting gummy bears in your lungs. The larynx is also what allows us to make sound for talking
or singing. To do this, you use your lungs to push a column of air through the larynx while using your laryngeal muscles to press together a pair of membranes called the vocal folds, or more commonly, your vocal chords. When you close the vocal folds like this, the air you push out through them makes them vibrate, and this vibration leads to sound. So the next time you're just shrieking and shrieking until the cashier finally accepts your expired coupon,
thank your larynx. There are several factors that can all have some effect on the fundamental frequency of a person's voice, like the size of the larynx and the differential development of facial bones and muscles. But the most important factor to talk about is the length of the vocal folds. If you pluck a string, the length of the string affects the frequency of the note that plays. Think about a guitar. When you press a string down to a
higher fret. On a guitar, you shorten the length of the part of the string that vibrates when you pluck it, and this produces a higher note. The same thing happens inside your larynx. The longer the vocal fold, the lower the note. During puberty, both boys and girls experience growth of the vocal folds, leading to lower voices, but the male hormone testosserone, which is released by the testicles during puberty, typically causes boys vocal folds to grow longer and thicker
than girls. On average, adult women have vocal folds somewhere around ten millimeters long, while adult men have vocal folds in the neighborhood of sixteen millimeters. Consequently, women are up there on the upper frets, soloing into oblivion like a high school kid who just learned how to play eruption by Van Halen, and men are letting the open strings ring like the intro of nothing else matters by Metallica.
Now here's some bonus information for you. Everyone knows what happens when you inhale some helium from a party balloon or you know, straight from an industrial helium transport truck. Your voice pitch gets higher. This is because helium is less dense than air. But did you know you can reverse the effect and give yourself a deep, booming bridge troll voice by breathing a gas with a higher density than your air, like zenon or sulfur hexafloor a ride.
But remember, your body needs air to live, and breathing anything other than air can be dangerous, so don't try this at home. Today's episodes written by Joe McCormick and produced by Tyler Clang. If you miss Christian you can find him on his new pop culture podcast super Context, And of course, for more on this and lots of other deep topics, visit our home planet, how Stuff Works dot com.