I very much agree and it saddens me often when I see folks dial it up to 1.5x or 2x "because it is boring otherwise". They might think they just get as much, only in half the time, but I'd hypothesize that they retain less because the mind needs some time to digest.
Similar with the trend to auto-cut pauses that speakers make, just to cram in more text into a youtube video. Destroys not just the pacing but any chance for the mind to take its time.
There’s a great lecture on giving lectures by an MIT prof. He says you can give no more than 3 ideas per hour, and you must repeat yourself at least 3 times for each idea. And while, part of his thesis is because people might miss something due to their attention, and needs of the group vs individual I think his experience is still highly relevant. I know that I don’t learn as much unless there’s room for almost boredom. I find there is a feeling similar to boredom that I have to experience to really internalize something. It’s almost like I can feel the neurons rewiring (though I suspect it might just be an emotion that encourages the energy expenditure necessary for learning). If I skim, or do doubletime, then that feeling usually never comes, and there’s a good chance my future recall will be poor…
When I’m understimulated by a teacher, my mind wanders. I’ll start thinking about something else entirely. When my mind comes back, I’ll have missed a couple minutes of content. I can overcome this with willpower, but doing so is exhausting.
Playing videos at 1.5-2x fixes the problem entirely. My attention is held without any effort.
If a concept is new or difficult enough, I just slow the video back down or pause it whenever I need to think things through.
I don't think you can make blanket statements. Consider:
1. Teacher 1 speaks at 100 words per minute.
2. Teacher 2 speaks at 50 words per minute, for the exact same content as Teacher 1.
You're not really losing anything by playing Teacher 1 at normal speed vs Teacher 2 at 2x speed. For every learner, there will be an optimal teaching speed for a given topic. This may mean listening to some audio at normal speed, some at higher speeds, and some even at slower speeds. I always customise my playback speed to the specific content I'm trying to learn.
Those two teachers will rarely say the same words. Chances are, teacher 2 chooses their words more carefully, and gives you then space to absorb that higher information density. In the end, both may communicate the same amount of information.
It's not about the rate of speaking but rather about what is actually being spoken. I am currently going through the Neetcode DSA course and it's just obnoxious. His video on Union Find, a 15 LoC algorithm, is 20 minutes.
I'd argue (as the article does), that you don't 'really' learn from watching stuff, fast or slow, but from actually working with and doing. This is completely obvious in the physical domain. You could take a ten year course on the basketball free throw and watch a billion hours of video on it, but then when you get on the court and actually do it - you're going to shoot pretty much like somebody who's never shot before.
And I think the same is true in academic domains. If you're trying to think about something consciously, you're going to do a poor job of it. And the only way to get the unconscious competence is through a bunch of 'doing'. Chess is a great example of this because it's purely mental yet again you're never going to gain any degree of significant competence without playing a lot. Interestingly this even applies after mastery. A master who has played e.g. 1. e4 their entire life and then swaps to 1. d4 isn't going to be playing at the same level as he plays 1. e4 even if watches thousands of hours of videos on it beforehand. That connection you make by doing and interacting with things is just critical.
It is a spectrum. If you give your mind some space, it will start churning through the key ideas, fill in gaps, turn things upside down, ask questions. That starts during the explanations and their pauses. And ideally you have some empty time right after to think about it, maybe do an exercise, maybe try to explain it to somebody. Work it, like a good dough.
2x listening suffocates this process. Like too little sugar or too low temperature or too little rest for your yeast dough. It might "feel" good but you are missing out so much...
I remember reading a study a while back about learning from videos at 1.5x to 2x speed. The key observation that actually made the learning more efficacious was to watch the video at 2x speed two times back to back. Apparently, this method was also better than watching the video one time at normal speed. I suppose it's because one get twice the exposure for the same amount of time.
I haven't looked for the study, but I can if you are truly curious.
I think there was a study omparing watching an educational video in 1x speed and watching it two times back to back in 2x speed equating the time spent on the material, which found the second group faired better.
Though it's not the question I asked. Would the second group fair somewhere close to the first if it only had listened once?
(I don't buy the argument that this would not be fair since they would use the extea time to watch more stuff ... because that's rarely what people do with their extra time. Especially not watching the same thing again.)
Similar with the trend to auto-cut pauses that speakers make, just to cram in more text into a youtube video. Destroys not just the pacing but any chance for the mind to take its time.
I'd love to see studies about this.