Comment by eru 20 hours ago
> The brain does not retain information that it does not need.
Sounds very plausible, though how does that square with the common experience that certain skills, famously 'riding a bike', never go away once learned?
I think a better way to say it is that the brain doesn't commit to long term memory things that it doesn't need.
I remember hearing about some research they'd done on "binge watching" -- basically, if you have two groups:
1. One group watches the entire series over the course of a week
2. A second group watches a series one episode per week
Then some time later (maybe 6 months), ask them questions about the show, and the people in group 2 will remember significantly more.
Anecdotally, I've found the same thing with Scottish Country Dancing. In SCD, you typically walk through a dance that has 16 or so "figures", then for the next 10 minutes you need to remember the figures over and over again from different perspectives (as 1st couple, 2nd couple, 3rd couple etc). Fairly quickly, my brain realized that it only needed to remember the figures for 10 minutes; and even the next morning if you'd asked me what the figures were for a dance the night before I couldn't have told you.
I can totally believe it's the same thing with writing with an LLM (or having an assistant write a speech / report for you) -- if you're just skimming over things to make sure it looks right, your brain quickly figures out that it doesn't need to retain this information.
Contrast this to riding a bike, where you almost certainly used the skill repeatedly over the course of at least a year.
> Sounds very plausible, though how does that square with the common experience that certain skills, famously 'riding a bike', never go away once learned?
I worked with some researchers who specifically examined this when developing training content for soldiers. They found that 'muscle memory' skills such as riding a bike could persist for a very long time. At the other end of the spectrum were tasks that involved performing lots of technical steps in a particular order, but where the tasks themselves were only performed infrequently. The classic example was fault finding and diagnosis on military equipment. The researchers were in effect quantifying the 'forgetting curve' for specific tasks. For some key tasks, you could overtrain to improve the competence retention, but it was often easier to accept that training would wear off very quickly and give people a checklist instead.
Such a good question - I hope someone answers with more than an anecdote (which is all I can provide) - I've found the skills that don't leave you like riding a bike, swimming, cooking are all physical skills. Tangible.
The skills that leave: arguments, analysis, language, creativity often seem abstract and primarily if not exclusively sourced in our minds
Riding a bike is a skill rather than what we would call a “memory” per se. It’s a skill that develops a new neural pathway throughout your extended nervous system bringing together the lesser senses of proprioception and balance. Once you bring these things together you then go on to use them for other things. You “know” (grok), rather than “understand” how a bike stays upright on a very deep physical level.
Closer to the truth is that the brain never completely forgets something, in the sense that there are always vestiges left over, even after the ability to recall or instantly draw upon it is long gone. Studies show, for example, that after one has "forgotten" a language, they're quicker to pick up it again later on compared to someone without that prior experience; how quickly being time dependent, but more quickly nonetheless.
OTOH, IME the quickest way to truly forget something is to overwrite it. Photographs being a notorious example, where looking at photographs can overwrite your own personal episodic memory of an event. I don't know how much research exists exploring this phenomenon, though, but AFAIU there are studies at least showing that the mere act of recalling can reshape memories. So, ironically, perhaps the best way not to forget is to not remember.
Left unstated in the above is that we can categorize different types of memory--episodic, semantic, implicit, etc--based on how they seem to operate. Generalizations (like the above ;) can be misleading.