Saturday, February 7, 2015

What do the Grammys and The Fear of Snakes Have in Common?

The Grammys are this Sunday and one of my favorite artists, St. Vincent, is nominated for Best Alternative Music Album. The first track on her album is entitled "Rattlesnake" (which is awesome), but its lyrics may not represent snakes in a good way. This song is about the fear and intensity of being isolated in the wilderness for the first time. She wrote the song after an experience in the American Southwest where she wandered alone through the desert one night and thought she heard a rattlesnake’s rattle. Based on the song’s lyrics and music composition, this was a frightening experience for her. Would this song have a different title if rattlesnakes were not feared by people?



Here are the lyrics to the song Rattlesnake by St. Vincent:

Follow the power lines back from the road
No one around so I take off my clothes
Am I the only one in the only world?

I see the snake holes dotted in the sand
As if the Seurat painted the Rio Grande
Am I the only the one in the only world?

Sweating, sweating no one is behind me
Sweating, sweating no one will ever find me

The only sound out here is my own breath
And my feet stuttering to make a path
Am I the only one in the only world?

Is that the wind finally picking up?
Is that a rattle sounding from the brush?
I'm not the only one in the only world

Running, running, running rattle behind me
Running, running, no one will ever find me
Running, running, running rattle behind me
Running, running, no one will ever find me
Sweating, sweating, sweating, rattle behind me
Running, running, no one will ever find me
Sweating, sweating, sweating, rattle behind me
Running, running, no one will ever find me


A broad theme of the song centers on a fear of snakes. Is this fear justified? Long long ago, snakes were in fact a predator of early man (and still prey on some hunter-gatherers today!) and so we hold an evolutionary reason for why we would be afraid of snakes. In the song, she becomes frightened after hearing the rattling sound of a rattlesnake. A lot of studies have focused on fear responses related to seeing to snake, but not hearing the sound of a snake. Is our response to hearing a snake different from when we see one? 

Rattlesnakes are good at hiding in the grass. Our ability to quickly detect 
snakes is important. Photo by B.J. Putman 


Past studies have shown that humans possess the keen ability to quickly detect hidden snakes, and this has led to the Snake Detection Theory which states that our strong need to detect snakes in the past has led to human’s crazy snake-finding skills which are no longer necessary for our current survival (Soares and Esteves 2014; Van Strien et al. 2014). However, our ability to find snakes quickly does not explain the psychological fear many people have towards snakes (Tierney and Connolly 2013). Some scientists believe that the fear of snakes is transmitted from mother (or father) to the child – it is a learned response. In support of this, both human and primate infants show greater fear of snake-like objects only after observing fearful reactions to the objects by their mothers (Mineka et al. 1984, Gerull and Rapee 2002)


Our fear of snakes stems largely from cultural learning.
The Snakes In Hats Tumblr is trying to change people's perception of snakes,
cause how can you NOT love animals wearing tiny hats? Adorable.


As past studies have shown, the fear that occurs after seeing a snake is likely culturally learned (unjustified), but the fear that occurs after hearing rattling may be justified. Little to no studies have been done on human responses to rattlesnake rattling, but research on other animals suggests that hearing a snake can indeed be startling, but differs from seeing a snake.  

As an example (and plug for my own study system), ground squirrels respond fearfully to rattlesnake rattling. They can even discriminate between more and less dangerous rattlesnakes just based on sound. Larger more dangerous snakes produce rattling with higher amplitudes and lower frequencies – louder and lower in pitch – than smaller snakes. In addition, warmer more dangerous rattlesnakes produce louder rattling with faster click rates than colder less dangerous rattlesnakes (Rowe and Owings 1996). In one study, squirrels tail flagged and stood alert more following playbacks of recorded rattling sounds from more dangerous snakes (Swaisgood et al. 2003). 


Both warmer snakes and larger snakes have higher amplitude rattling - they are very loud! 
Taken from Rowe and Owings 1996.


Dan Blumstein, researcher at UCLA, has been studying what he calls – The Sound of Fear (dun dun duuuun). He’s looked into the acoustic qualities of sounds associated with fear from the alarm calls and screams of mammals to the soundtracks of Hollywood films (like the music during the classic shower scene in Psycho). His team has found that sounds that make us aroused/jumpy/uneasy contain more noise than neutral sounds. What does that mean exactly? Well, noise doesn’t sound nice because it contains non-linearities, or sound wave distortions. Noise is more complex and more atonal than sounds we consider soothing. We may find noise so disturbing because its acoustic characteristics are more variable and somewhat unpredictable, making us less likely to habituate to them (Blesdoe and Blumstein 2014). Marmots (Blumstein and Récapet 2009), Great-tailed Grackles, (Slaughter et al. 2013), and White-crowned Sparrows (Blesdoe and Blumstein 2014) respond “fearfully” to noise.





The rattle is currently used by rattlesnakes for defense – warning potential predators of the snake’s dangerousness (see previous blog post). It makes sense that the sound of rattling be associated with fear to deter other animals from harming the threatened rattlesnake. Indeed, the rattling of a rattlesnake is noisy and atonal like screams and alarm calls. Its distinct acoustic qualities may justly explain our fear after hearing but not seeing a rattlesnake. The Rattlesnake song itself is jarring because of its use of dissonant and atonal sounds. In the end, we see that St. Vincent was likely expressing a true emotional response to a scary sound, which is also a conserved evolutionary response across distantly related species. 


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5 comments:

  1. What a great and insightful article, we did some interviews which might be of interest http://bit.ly/OQjjYk

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  2. There was also a good podcast on this subject on NPR recently:

    http://www.npr.org/programs/invisibilia/377515477/fearless

    which prompted me to read the Tierney & Connolly paper you cited above. I was surprised that the evidence for an innate fear of snakes was not stronger, considering that you hear about it all the time.

    Also, it appears that St. Vincent won her Grammy!

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    Replies
    1. Thanks Andrew! It's interesting that I couldn't find any studies on human responses to hearing rattling sounds of rattlesnakes. It would be a cool companion study to all the countless studies that focus on human detection of snake scale patterns (even if humans were never preyed upon by rattlesnakes).

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  3. Here's one anecdotal data point: My mother was deathly afraid of snakes - all kinds - yet I grew up with no innate fear of them at all. Indeed, I was fascinated by them, and would invariably try to catch or otherwise interact with every snake I came across. This was on a ranch in the Rogue Valley in Oregon, where there were plenty of Gopher Snakes and Garter Snakes, but no Rattlesnakes. When I found a Gopher snake in the oak-madrone-manzanita habitat, and tried to catch it, sometimes it would do the tail-shaking-in-dry-leaves thing; and invariably this provoked an automatic fear response in me, even though I knew beyond doubt that it was not a Rattler! So for me anyway, the response to the rattling sound seems to have been innate, and separate from visual detection. Even in rattlesnake country, the sight of a rattler did not usually produce a strong fear response, but the buzz certainly did!

    Tim Bray, Albion, California
    ecologyhour.wordpress.com

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  4. Never heard about this song. I might be checking this on youtube and if I like the song I will request this to my favorite Philippine radio station. :)

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