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SOUNDS ODD #27 by Elizabeth Holmes
Fun Facts on the Science of Sound
Coffee Hallucinations? Yup.
Caffeine Affects What We Hear

December 22, 2015

The next time you’re under pressure to complete an audio editing project, you might want to avoid that extra cup of coffee. 

Why?  Because you’re likely to hear things that aren’t there. High coffee intake can cause auditory hallucinations!  

Researchers at La Trobe University, Australia conducted a study on nearly a hundred non-clinical individuals to determine how they perceived sound under specific conditions.  Subjects were divided into groups that were exposed to high stress, low stress, high caffeine levels and low caffeine levels. 

All participants listened to white noise (which includes every frequency within the range of human hearing). 

Then, they were asked to report whenever they heard Bing Crosby sing "White Christmas.” 

Significantly, the song was never actually played! Nevertheless, individuals who were either under high stress or who had just consumed high levels of caffeine (or both) reported hearing the song.  


Caffeine is the most widely consumed psychoactive substance in the world. It is largely unregulated and completely legal. 

Caffeine stimulates the central nervous system in varying degrees. Here are some reference ranges for the caffeine in coffee:     
  • 80 to 135 mg caffeine in 1 cup of brewed coffee
  • 115 to 175 mg caffeine in 1 cup of drip coffee
  • 100 mg of caffeine in a shot of espresso  
Don’t forget that lightly roasted beans actually contain more caffeine than dark roasts! 

Researchers in this study found that five cups of coffee or more per day can trigger an auditory hallucination.  

So, the next time you’re relying on your finely-tuned sensibilities to hear every nuance in your audio tracks, skip that extra cup of joe. (Either that, or hope that the person who’s listening on the other end has had as much coffee as you have!)  

Adapted from: Too Much Coffee Can Make You Hear Things That Are Not There by Christian Nordqvist, Medical News Today.

Elizabeth Holmes is a writer, voice actor, and staff editor at VoiceOverXtra, based in Northern California. She is also editor of VoiceOverXtra's book division, including Voice Over Legal, by voice actor / attorney Robert Sciglimpaglia.

Earlier Sounds Odd Columns:

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Comments (3)
Howard Ellison
1/1/2016 at 12:58 PM
That's incredibly interesting! Long ago an alternative physician advised my wife and me never to drink coffee, and voice-wise that's a good tip. Green tea for us.

In hospital a few years back, under morphine, I heard my drip feed nutrition machine announce "Howard, special CNN Report - your lunch today will be…"

What amazing patient care! I sat up and pressed my ear to the machine to locate the loudspeaker, which sounded clearer as I got near. Completely believable, and to this day I can't quite believe the thing was in reality silent.
12/22/2015 at 12:11 PM
Good job, Elizabeth! And now we know why newscasters at CNN hear things that aren't there...! =))
Ken Farmer
12/22/2015 at 7:39 AM
Ha! Just like authors have a term, 'their lying eyes' when they are proofing their work. Their mind knows what is supposed to be there and miss that they've left out a preposition or maybe a conjunction, now narrators have their 'lying ears'...Who knew?
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