7 Scientific Studies About How Animals React to Music

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iStock

Music is pretty universally enjoyed ... when it comes to people. Animals, on the other hand, have diverse reactions to tunes. For every Ronan the head-bopping sea lion, there are plenty of creatures that can't keep the beat. Here are seven scientific discoveries about how some animals react to music, either created by humans or themselves. 

1. DOGS IN KENNELS MIGHT BE LESS STRESSED WHILE LISTENING TO CLASSICAL MUSIC.

In a 2012 study [PDF] published in The Journal of Veterinary Behavior, researchers from Colorado State University monitored the behavior of 117 kenneled dogs, including their activity levels, vocalization, and body shaking. The researchers played a few different types of music to the dogs, including classical, heavy metal, and an altered type of classical music. They also observed the dogs' behavior when no music was playing at all. They found that the dogs slept the most while listening to all kinds of classical music, indicating that it helped them relax. The dogs had the opposite reaction to the metal music, which provoked increased body shaking—a sign of nervousness.

The researchers noted the similarities between dogs and people when it comes to classical music. “These results are consistent with human studies, which have suggested that music can reduce agitation, promote sleep, improve mood, and lower stress and anxiety,” they wrote. They also point out that heavy metal music has anxiety-inducing effects on some people as well.

2. CATS DON'T CARE ABOUT HUMAN MUSIC, BUT SCIENTISTS ARE ABLE TO CREATE MUSIC THAT THEY DO ENJOY. 

Cats either don't care for, or are pretty indifferent to, human music. Thankfully, Charles Snowdon, a psychologist at the University of Wisconsin-Madison, David Teie, a composer at the University of Maryland, and Megan Savage, formerly of the University of Wisconsin-Madison and now a Ph.D. student at SUNY-Binghamton, have developed music that contains frequencies and tempos similar to the ones cats use to communicate. We tested some of the songs on one of our editor's cats earlier this year; you can listen to samples of the songs here.

Snowdon and Savage went to 47 households with cats and played them music, including two classical songs and two songs developed for felines. When the researchers played the latter, the cat was more likely to move towards the speaker, or even rub up against it, according to their study, which was published in the journal Applied Animal Behavior Science earlier this year. Interestingly, young and old cats reacted to the cat songs the most positively. Middle-aged cats showed more indifference.

3. IT'S ALSO POSSIBLE TO MAKE MONKEY MUSIC.

Cats weren't the first animals Snowdon, Savage, and Teie made species-specific music for. In 2009, they developed songs that mirrored the pitch of monkey calls. For their study, which was published in the journal Biology Letters, the scientists played the music for tamarin monkeys. Songs that were inspired by the calming calls the animals make caused the monkeys to relax; they even ate more while listening to those songs. But when the researchers played music that contained sounds similar to ones the monkeys make when they’re expressing fear, the monkeys became agitated. (You can listen to the songs here.) The monkeys were mostly indifferent to human music—their behavior didn't noticeably change when they were listening to Nine Inch Nails, Tool, or Samuel Barber. But, interestingly, when they heard “Of Wolf and Man” by Metallica, they grew calmer.

4. COWS PRODUCE MORE MILK WHEN THEY'RE LISTENING TO RELAXING MUSIC. 

In 2001, researchers at the University of Leicester played various songs to 1000-strong herds of Friesian dairy cows. Over a period of nine weeks, the researchers alternated between fast music, slow music, and silence for 12 hours each day. They found that calming music—like R.E.M.'s "Everybody Hurts," Simon & Garfunkel's "Bridge Over Troubled Water," and Beethoven's "Pastoral Symphony"—actually resulted in the cows producing 3 percent more milk—0.73 liters per cow per day. One of the lead researchers, Dr. Adrian North, told the BBC, “Calming music can improve milk yield, probably because it reduces stress.” The cows were not so into “Space Cowboy” by Jamiroquai or “Size of a Cow” by Wonderstuff.

5. ELEPHANTS MIGHT BE BETTER AT PLAYING MUSIC THAN HUMANS ARE.

Elephants are already known for their ability to paint with their trunks, but it turns out that they might be musically inclined as well. (Just check out this viral video of elephants swaying their trunks to violin music!) In northern Thailand, a conservationist named Richard Lair put together the Thai Elephant Orchestra, in which 16 elephants play specially developed instruments like steel drums and even harmonicas. Neuroscientists who have studied the music of the Thai Elephant Orchestra have determined that the animals are able to keep a very stable tempo on a large drum—even more stable than a human can.

6. BIRD BRAINS REACT TO MUSIC IN A MANNER SIMILAR TO HUMAN BRAINS. 

Birds are probably the most well-known singers of the animal kingdom. A few years ago, researchers at Emory University set out to learn whether birds are actually making music, like humans do. To find out, they examined the brains of both male and female white-tailed sparrows as they listened to the sounds of male birds.

When humans listen to music, our amygdalae often light up in response. It turned out that female white-tailed sparrows had similar brain responses to the bird sounds. The part of their brain that’s similar to the amygdala lit up while listening to the male’s song. The male birds, on the other hand, had brain reactions similar to when humans listen to music they don’t like. Sarah Earp, the study's lead researcher, explained, “We found that the same neural reward system is activated in female birds in the breeding state that are listening to male birdsong, and in people listening to music that they like.”

7. FISH KNOW THE DIFFERENCE BETWEEN COMPOSERS.

In 2013, a study was published in the journal Behavioral Processes that revealed that goldfish could be trained to distinguish between composers. Researchers at Keio University used pieces of music by two composers in the study: Igor Stravinsky and Johann Sebastian Bach. The goal was to train the goldfish to gnaw on a ball filled with food when the correct composer’s music was playing. One group of fish got Stravinsky and a separate group got Bach. When the fish heard music, they went to gnaw on the ball and were rewarded with food. Once the fish were correlating a composer’s music with the reward, the researchers tried playing the other composer’s music. The goldfish didn’t gnaw on the ball at that point, indicating that they knew enough about the pitch and timbre of their composer to not associate the novel music with food.

All images courtesy of iStock

Why Does Humidity Make Us Feel Hotter?

Tomwang112/iStock via Getty Images
Tomwang112/iStock via Getty Images

With temperatures spiking around the country, we thought it might be a good time to answer some questions about the heat index—and why humidity makes us feel hotter.

Why does humidity make us feel hotter?

To answer that question, we need to talk about getting sweaty.

As you probably remember from your high school biology class, one of the ways our bodies cool themselves is by sweating. The sweat then evaporates from our skin, and it carries heat away from the body as it leaves.

Humidity throws a wrench in that system of evaporative cooling, though. As relative humidity increases, the evaporation of sweat from our skin slows down. Instead, the sweat just drips off of us, which leaves us with all of the stinkiness and none of the cooling effect. Thus, when the humidity spikes, our bodies effectively lose a key tool that could normally be used to cool us down.

What's relative about relative humidity?

We all know that humidity refers to the amount of water contained in the air. However, as the air’s temperature changes, so does the amount of water the air can hold. (Air can hold more water vapor as the temperature heats up.) Relative humidity compares the actual humidity to the maximum amount of water vapor the air can hold at any given temperature.

Whose idea was the heat index?

While the notion of humidity making days feel warmer is painfully apparent to anyone who has ever been outside on a soupy day, our current system owes a big debt to Robert G. Steadman, an academic textile researcher. In a 1979 research paper called, “An Assessment of Sultriness, Parts I and II,” Steadman laid out the basic factors that would affect how hot a person felt under a given set of conditions, and meteorologists soon used his work to derive a simplified formula for calculating heat index.

The formula is long and cumbersome, but luckily it can be transformed into easy-to-read charts. Today your local meteorologist just needs to know the air temperature and the relative humidity, and the chart will tell him or her the rest.

Is the heat index calculation the same for everyone?

Not quite, but it’s close. Steadman’s original research was founded on the idea of a “typical” person who was outdoors under a very precise set of conditions. Specifically, Steadman’s everyman was 5’7” tall, weighed 147 pounds, wore long pants and a short-sleeved shirt, and was walking at just over three miles per hour into a slight breeze in the shade. Any deviations from these conditions will affect how the heat/humidity combo feels to a certain person.

What difference does being in the shade make?

Quite a big one. All of the National Weather Service’s charts for calculating the heat index make the reasonable assumption that folks will look for shade when it’s oppressively hot and muggy out. Direct sunlight can add up to 15 degrees to the calculated heat index.

How does wind affect how dangerous the heat is?

Normally, when we think of wind on a hot day, we think of a nice, cooling breeze. That’s the normal state of affairs, but when the weather is really, really hot—think high-90s hot—a dry wind actually heats us up. When it’s that hot out, wind actually draws sweat away from our bodies before it can evaporate to help cool us down. Thanks to this effect, what might have been a cool breeze acts more like a convection oven.

When should I start worrying about high heat index readings?

The National Weather Service has a handy four-tiered system to tell you how dire the heat situation is. At the most severe level, when the heat index is over 130, that's classified as "Extreme Danger" and the risk of heat stroke is highly likely with continued exposure. Things get less scary as you move down the ladder, but even on "Danger" days, when the heat index ranges from 105 to 130, you probably don’t want to be outside. According to the service, that’s when prolonged exposure and/or physical activity make sunstroke, heat cramps, and heat exhaustion likely, while heat stroke is possible.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

This article has been updated for 2019.

Chimpanzees Bond by Watching Movies Together, Too

Windzepher/iStock via Getty Images
Windzepher/iStock via Getty Images

Scientists at the Wolfgang Kohler Primate Research Center in Germany recently discovered that, like humans, chimpanzees bond when they watch movies together, the BBC reports.

In the study, published in Proceedings of the Royal Society B, researchers stationed pairs of chimpanzees in front of screens that showed a video of a family of chimps playing with a young chimp. They found that afterward, the chimps would spend more time grooming and interacting with each other—or simply being in the same part of the room—than they would without having watched the video.

They gave the chimps fruit juice to keep them calm and occupied while they viewed the video, and they chose a subject that chimps have previously proven to be most interested in: other chimps. They also used eye trackers to ensure the chimps were actually watching the video. If you’ve ever watched a movie with friends, you might notice similarities between the chimps’ experience and your own. Drinks (and snacks) also keep us calm and occupied while we watch, and we like to watch movies about other humans. Since this study only showed that chimps bond over programs about their own species, we don’t know if it would work the same way if they watched something completely unrelated to them, like humans do—say, The Lion King.

Bonding through shared experiences was thought to be one of the traits that make us uniquely human, and some researchers have argued that other species don’t have the psychological mechanisms to realize that they’re even sharing an experience with another. This study suggests that social activities for apes don’t just serve utilitarian purposes like traveling together for safety, and that they’re capable of a more human-like social closeness.

The part that is uniquely human about this study is the fact that they were studying the effect of a screen, as opposed to something less man-made. The chimps in question have participated in other studies, so they may be more accustomed to that technology than wild apes. But the study demonstrates that we’re not the only species capable of social interaction for the sake of social interaction.

[h/t BBC]

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