[Originally posted on Medium]
Over the past couple of years, I’ve started to consume more and more information through spoken audio — the explosion of new podcasts and the production of great audiobooks has made listening to that content an irreplaceable part of commuting, exercising, or relaxing.
Very early on in my listening journey, I encountered a temptation that all podcast junkies are forced to face: the speed slider. In Overcast, I can increase the speed to a blistering 2x. The Audible app supports 3x speed, which is approaching “Motormouth” John Moschitta territory. For podcasts, I now hover around 1.7x and normal speed has become nearly unbearable.
As I’ve grown accustomed to higher speeds, I’ve wondered if the typical listener of audiobooks/podcasts can listen at greater than 1x speed without significant comprehension loss. At what point are speed-listeners short-changing their comprehension? Based on the research I was able to find, not only is it possible to comprehend spoken audio at significantly higher-than-normal rates of speed, the average person can train themselves to improve comprehension and actually prefers listening at a rate of speed that is higher than normal.
We are amazing listeners
Starting in the late fifties, researchers began experimenting with time-compressed speech and measuring the ability of subjects to comprehend material at high rates of compression. They determined that the average adult can readily comprehend spoken audio at 2X speed or at a compression rate of 50% [1]. This roughly corresponds to 275 words per minute. Although compression rate is a more helpful guide, words per minute is a good proxy that keeps things simple. Given that the typical conversational speaking rate ranges from 140–180 words per minute, we usually are able to comprehend even the fastest talkers [2].
Now how does this translate to audiobooks and podcasts? A middle value of 150 wpm seems like a reasonable estimate for the average audiobook, and aligns with the research I did. However, because podcasts are more tightly edited and are much more conversational, my hunch was that the wpm rate would be on the higher end. This was proven out through analyzing transcripts for several podcasts I listen to. I selected several episodes on YouTube that have automatic captions enabled and then wrote a ruby script to parse the subtitle files. Here’s a graph for Dan Carlin’s Hardcore history:
I calculated WPM rates for each minute throughout the podcast — I’m sure there’s a better way to do this.
We see that episodes hover in the 140–190 wpm range. At a 1.5x speed, we’d see roughly 240–285 wpm which is close to the 275 wpm ceiling. Provided that the material being listened to isn’t overly complex [e.g. a conversational podcast], it is well within the average person’s ability to process a typical podcast at 1.5x speed.
We can improve our listening comprehension
Another remarkable discovery is that our ability to listen and comprehend at high rates of speed is a highly improvable skill. According to time-compression research, with as little as 8–10 hours of training, we can comprehend material at “substantially higher speeds” than 2x [3]. While I’m not clear on the specifics of what kinds of training would facilitate significant improvement, it seems reasonable that listening to one season of Serial [or any enjoyable podcast] at faster than 1x could yield increasing comprehension benefits for the listener.
This is further emphasized in a study that looked at blind students and their preferred rate of listening to college lectures. Researchers found that their preferred rate ranged from 236–275 wpm [4]. Given their focus on listening as a primary sensory input, they were able to comfortably process information far faster than most people can comfortably speak. Presumably this was a learned skill, based on necessity.
We have a natural preference for speed
Finally, it is comfortable on some level to listen to spoken audio at a faster than normal speaking rate. In the last study I mentioned, sighted students were also tested and their preferred rate of listening was 212 wpm [82% compression]. Once we realize we can “increase the communication capacity of the ear”, it becomes pleasurable and natural to listen at a higher rate of speed.
What now?
Given that speed-listening is a valid way to increase our learning per minute spent, we can view it as a valuable tool at our disposal. However, when comprehension or pure enjoyment are ultimately the goal, the speed with which we listen should be adjusted to meet our own personal objectives. To modify a line from Mortimer Adler’s How to Read a Book:
“Every [podcast] should be [listened to] no more slowly than it deserves, and no more quickly than you can [listen to] it with satisfaction and comprehension.”
This quote is a great guide as I choose what to listen to and how to listen to it. It’s in the back of my mind when I play Never Let Me Go at an enjoyable 1x speed. And it clears my guilt when flying through Marc Maron, Tim Ferriss, or Ben Thompson at 1.7x. And most importantly, it’s what causes me to sometimes stop the audiobook and pick up a good old fashioned paperback.
Sources
[1][2] Cognitive Factors in Auditory Performance : Context, Speed of Processing, and Constraints of Memory — Arthur Wingfield, Journal of Audiology [1996]
[3] Microsoft Research: Time-Compression: Systems Concerns, Usage, and Benefits
[4] Techniques, Perception, and Applications of Time-Compressed Speech — Barry Arons, MIT Media Labs
Full Disclosure, I’ve never been a fast reader. My comprehension suffers as my reading speed increases. Many of you may experience the same affliction, finding yourself flipping back pages, not having a clue what you just read.
In my quest to read faster and keep up my understanding, I investigated supplementing my print reading with audio programs. Whether it is a podcast or an audiobook, these formats seem to be a perfect balance of speed and learning.
Listening to programs is how many of us get our news and reading today. This change is due mostly to the hustle and bustle of today’s busy lifestyle. People listen on their commutes, others while doing chores around the house, or while exercising.
According to a Forbes article, audiobook sales alone have grown in double digits for the last seven years. With the most recent data showing sales at almost 1 Billion dollars in 2018.
These formats have become a supplement and, in some cases, a substitute for the written word. As a writer, this may sound counterproductive. Most writers will tell you that being a well-rounded print reader is vital to the writing process. I believe we can compromise and make room for both. I, for instance, tend to read more nonfiction and listen to more fiction.
What if you could listen faster?
A while back, a friend and I were discussing an audiobook we were reading. The book was enjoyable, but I commented that the narrator was a tad annoying. His next statement changed the way I listen to audiobooks.
He said, “Oh, I just change the speed of the playback, and his voice becomes much better.”
Until that point, changing the playback speed of an audiobook had never occurred to me. When I tried it, I realized he was right. Not only was it more comfortable listening to the narrator, but it had the bonus of taking less time to finish the book.
Many of you may already do this with audio. This made me wonder, how fast can one actually listen to the spoken word and still comprehend the meaning. After a bit of research, I found out it’s much quicker than you would think.
In a study done at the Hertie Institute for Clinical Brain Research, an average sighted person can understand speech at six syllables per second. I say sighted because, in their study, they found some blind people can listen and comprehend speech at an astonishing 25 syllables per second. The researchers show that a blind person can repurpose parts of their brains used for visual processing and use it for auditory processing. Talk about a brain hack.
Here is an example of speech at those speeds.
You may be thinking the same thing I was when I read the article. Could we do that with our brains? It turns out you can do better than six syllables a second, but you will need to work at it.
What can you do?
Simple, you practice listening. You are already going to listen to that audiobook or podcast anyway. You might as well hack your brain while you are at it.
Try this exercise:
- Start at a comfortable speed for you.
- Listen for ten minutes at that speed.
- Now change the playback to the next level.
- Listen for another 10 minutes.
- Change it again.
- Keep changing every 10 minutes until you get to a rate that you start to feel some stress. You will know when you get there, because you will be concentrating on the words, and your comprehension will fall.
- Now go back to the speed before this one, this is your current max speed.
- Listen at the max speed for as long as you can.
- Repeat the process every day or two and you should see an improvement in your max speed.
You may find that you can’t listen as long at these speeds, you tire faster and feel more stress. It is a normal reaction as your brain adapts. The idea is to get your mind more comfortable listening at faster speeds.
Some caveats:
- Some narrators are harder to understand at faster speeds. It is because each of us has unique tones and intonations in our voice. You will find that you have to lower your rate for some people and raise it for others.
- You may also discover you have favorite narrators that you will enjoy listening to at a much slower speed. Bill Bryson and Neil Gaiman are my personal favorites. Their accents and natural speaking skills combine to bring joy to my ears.
- Some narrators are better at higher speeds. One particular narrator for me is like nails on a chalkboard, but if I turn up the playback speed, his voice flattens out.
I hope you take the challenge and increase your listening skills. Just think of all that extra content you could listen to each day by only a slight increase in speed.