
To Remember, the Brain Must Actively Forget - digital55
https://www.quantamagazine.org/to-remember-the-brain-must-actively-forget-20180724/
======
jeffwass
Relevant convo between Sherlock Holmes and John Watson (My choice of Italics
highlights).

Below excerpt from _A Study in Scarlet_ , Sir Arthur Conan Doyle, 1887.

——

My surprise reached a climax, however, when I found incidentally that he was
ignorant of the Copernican Theory and of the composition of the Solar System.
That any civilized human being in this nineteenth century should not be aware
that the earth travelled round the sun appeared to be to me such an
extraordinary fact that I could hardly realize it.

“You appear to be astonished,” he said, smiling at my expression of surprise.
_“Now that I do know it I shall do my best to forget it.”_

“To forget it!”

“You see,” he explained, “I consider that a man’s brain originally is like a
little empty attic, and you have to stock it with such furniture as you
choose. A fool takes in all the lumber of every sort that he comes across, so
that the knowledge which might be useful to him gets crowded out, or at best
is jumbled up with a lot of other things so that he has a difficulty in laying
his hands upon it. Now the skilful workman is very careful indeed as to what
he takes into his brain-attic. He will have nothing but the tools which may
help him in doing his work, but of these he has a large assortment, and all in
the most perfect order. It is a mistake to think that that little room has
elastic walls and can distend to any extent. _Depend upon it there comes a
time when for every addition of knowledge you forget something that you knew
before. It is of the highest importance, therefore, not to have useless facts
elbowing out the useful ones._ ”

“But the Solar System!” I protested.

“What the deuce is it to me?” he interrupted impatiently; “you say that we go
round the sun. If we went round the moon it would not make a pennyworth of
difference to me or to my work.”

~~~
vanderZwan
The flaw in the attitude of Sherlock Holmes is that he does not consider the,
for the lack of a better term, "compressibility" of knowledge. Then again,
Shannon wouldn't do his thing for another half century, so it would not be
fair towards Sir Doyle to expect him to have taken this into consideration.

The brain actually does a lot of lossy compression tricks to remember things
together, plus I doubt that knowledge about the Solar system takes up any
significant amount of space in the brain, since physics works with models.
Very "compressible" information, really. But if we look at how much lore
people remember about modern pop-culture trivia, like comics or TV series or
games, it's a different story. The amount of mental effort and "mind space"
that fans dedicate to remembering, say, World of Warcraft lore is mindblowing
to me at times.

~~~
Retra
I think there's a related problem that would have been understandable at the
time: if you don't understand how the world works, you are potentially missing
out on patterned information which allows one to form more accurate models of
the world across domains. The assumption that's made seems to be that
different problem domains are all independent, but that's not completely true.
That's probably the main reason that mathematics and language are so useful.

~~~
vanderZwan
> _The assumption that 's made seems to be that different problem domains are
> all independent, but that's not completely true. That's probably the main
> reason that mathematics and language are so useful._

To be fair, the effectiveness of multi-disciplinary research seems to only
have been acknowledged in recent decades, even though by and large the biggest
breakthroughs have almost always been thanks to people looking outside of the
silos of their field. The sciences are really "tribal", and it used to be much
worse.

For example, when I started studying in the early 2000s I remember the ML
bachelor (then: AI) having recently split off from CompSci and being super-
territorial.

I also heard stories of CompSci having split off from mathematics a few
decades before that, and during my Interaction Design (IxD) master I learned
that it separated from HCI in the nineties (short version: HCI was idolising
the methods of the quantitative sciences too much for its own design-oriented
good, IxD decided to bring in methods and insights from the qualitative
fields).

I wonder if this was better or worse in Doyle's time.

------
ehnto
Minor and probably not that interesting anecdote: I always struggled to
remember sequences of numbers. Even if I had looked at the number just a
fraction of a moment ago, they were gone. I would have to do things like
repeat them over and over or remember two numbers at a time. I was always
buzzing in my head anout remembering the numbers and that produced a noise
that I think made me forget.

Then I started cleaning up my attention span a bit, less social media, less
mindless scrolling, more thoughtful long term tasks and planning. It helped a
lot, but it wasn't perfect still.

Then one day I tried reading a number sequence once, not making a single noise
in my brain, and I jotted it down again with ease. It seemed the secret for me
was to trust my memory had the number in working memory somewhere, rather than
trying to persist it my concious stream of thought which inevitably garbled
it.

The brain is weird.

~~~
saiya-jin
hmm, I am a bit opposite - no issues with remembering even longer numbers
(learned long serial numbers of all posters on the wall as a child just out of
boredom), but introduce to me 2-3 people I haven't seen, and I simply can't
remember their names. Feeling like a incompetent idiot guaranteed.

Names stick like 2 seconds around in my memory and are gone. Heck sometimes
even a single person is an issue. My memory ain't greatest but for names
specifically it is almost not writable. Tried few mind tricks but not really
successful. I am sure there must be some way to get this to more acceptable
level, anybody has any idea?

~~~
jibreel
Me too, i can never quite seem to remember names, it can be very embarrassing,
sometimes i even forgot the names of my cousins i haven't seen in a long time.

My theory is that, we don't internalise names and link it to the respective
person for it to be anything memorable. but what do i know...

------
adriand
I remember sitting at a bar in a distant city in some other country one night,
and the person next to me, who I had just met that day, suggested that we do a
shot together. Now these shots were big, and it had already been quite the
night, and I remember thinking, "If I do this shot, it's probably the last
thing I'll remember tonight."

It was, but that's not the point of this anecdote. This experience gave me the
idea for the premise of a sci-fi story: a drug which, once taken, has no
affect on you whatsoever outside of one crucial impact, which is that whatever
happens while you're on it, you won't remember once it wears off a few hours
later.

The scientific findings related in this article seem to indicate that
developing such a drug would be possible. Would people take it? I suspect they
would, although I also suspect that it would lead to regrettable behaviour.
(That is probably, in fact, its chief advantage.) What about you - would you
take it?

Are experiences less meaningful if you don't remember them?

~~~
IAmGraydon
Such a drug exists. Namely, anything of the benzodiazepine class.

~~~
dhekir
Can it or has it been used for UX testing? Having a way to "reset" people for
interface testing would be useful. Preferably without side effects, of course.

~~~
deno
Drugging people with hypnotics to test your shitty UI? This is the most HN
thing I’ve seen in a long time ;)

------
8bitsrule
_If we remembered everything, he said, we would be completely inefficient
because our brains would always be swamped with superfluous memories._

Yet there are a few people who, it has elsewhere been claimed, can remember
details from every day of their life, on demand. What's 'superfluous' to one
of us may be essential to others... a strictly subjective judgement. Some of
us are specialists, others generalists.

The trouble with such reporting is that there's little science involved, and a
whole lot of anecdotal reportage. Of course, our brains are enormously
complex, having to operate in a wide diversity of human and chemical
environments. Given the number of variables, solid memory science has yet to
emerge ... in articles like this one, at least.

~~~
heed
I've heard of these people, but if I remember correctly they were of the type
to obessesively recall the events/details of their day - like a form of OCD.

~~~
demircancelebi
For the curious one, I think this is called Hyperthymesia.

------
misterprime
Looks like Married With Children was on to something back in '94:

"When the Bundy TV set blows its condenser, Al decides to try out for a place
on a new sports trivia game show, hoping to win $10,000 for a new TV set as
the first prize. But when he is denied because of his lack of personality, Al
tries to transfer his knowledge of sports to Kelly to win the show for him.
But for each fact that she takes in, another falls out."

[https://www.imdb.com/title/tt0642312/plotsummary?ref_=tt_ov_...](https://www.imdb.com/title/tt0642312/plotsummary?ref_=tt_ov_pl)

------
Aardwolf
> Eleven of those genes, they discovered, were still active on one side of the
> animals’ brains but not on the other, even after the animals had apparently
> forgotten about the shock.

What exactly does active genes mean here and how can they do that in a living
slug and be different on both sides? Afaik, genes are mostly constant
throughout one individuals' lifetime, and usually the same in all cells

With almost a GB of data in the DNA of a single cell and 100 billion human
brain cells, the DNA sounds like a great storage medium for memories (725
exabytes)! But that's not how it works, right?

~~~
daveguy
The entire genome in each cell contains all of the genes for every type of
cell in your body. In different types of cells and in different states certain
genes are upregulated and downregulated. Essentially the process for turning a
specific gene into the protein it codes for can be turned on or off. That is
what is meant by an active vs inactive gene.

Note: the activity of a neuron and the activity of a specific gene (eg rac1)
are two completely different kinds of activity. The first is electrochemical
activity and the second is production activity. Where changes in production
can change the physical number of receptors available for the electrochemcial
process.

------
eruci
Makes sense. It is best to forget useless things and fill the brain with
useful ones. I was also going to say something else, but I forgot.

~~~
ksec
Well, whether or not it is "useless" depends on the person. Most human have
emotional attachment to memories. And hence those that are more emotional (
whether it is inside or outside ) tends to remember things better and in tiny
details.

And I actually doubt we "forget" about it. It is not like a computer sudden
decide to do GC and you have more memory space. I think our brains tends to
archive those "useless" things into somewhere deep, that takes lot of energy
and take it back out.

I don't believe information is lost in our brain, it is most encrypted,
compressed ( lossy ) and stored differently.

~~~
jacobush
Apparently each time a memory is accessed, it gets written down back again.
Imperfectly.

------
bojo
As someone who has moved to Japan for the last ~12 years and speaks the
language daily, I struggle to remember terms I am absolutely postive I know
but can't recall while in the middle of conversations with my English speaking
employees. Or even worse, deep in personal thought I have to start googling
around to recall a term I know I know.

There are linguistic studies which show that this is the norm (i.e. as a
second language learner using said language daily, you begin to forget your
mother tongue), but I have to admit it is quite disconcerting when I have to
take a multi-second break to recall an uncommon word before I can carry the
conversation further.

I guess the moral of the story is that, yeah, you forget things you don't
actively use.

------
PascLeRasc
I recently started taking noopept for memory health and I'm getting a side
effect when I feel like I'm a college freshman again and don't know much about
whatever I'm doing. It's helpful because I try new things that I wouldn't
usually. I've learned a lot about bash and vim in the past two weeks as a
result and I've tried new playing styles on guitar, while in the past I'd just
play tabs from bands I like. I'd highly recommend it to anyone looking to
learn quickly and break through mental blocks.

------
sevagh
The book Behave by Robert Sapolsky describes this topic (among others) nicely.

[https://www.penguinrandomhouse.com/books/311787/behave-by-
ro...](https://www.penguinrandomhouse.com/books/311787/behave-by-robert-m-
sapolsky/9780143110910/)

~~~
maneesh
This book was fantastic, and elegantly laid out in how it described behaviors
that human beings take.

------
sctb
Related? [https://www.nature.com/news/the-unavoidable-cost-of-
computat...](https://www.nature.com/news/the-unavoidable-cost-of-computation-
revealed-1.10186).

------
dpweb
I know nothing of the neuroscience but I have a theory we look at memory
wrong. We see it like storage. You take a cup, put it in a cabinet, and bring
it out later.

But what about memories as your brain, not pulling it from storage, but
entirely regenerating the experience. So its remaking the cup every time, not
pulling it from the cabinet.

False/faulty memory is common. We’re regenerating the experience inaccurately.
Like if you drew a picture then had to draw it again. It would look the same
but slightly different. The cup after all if stored would always be retrieved
exactly as it was.

------
DoreenMichele
I only skimmed the piece, but it doesn't look like it touched on the fact that
the brain apparently "resets" during sleep (edit: specifically to foster new
memories the next day, from what I gather). I have seen several articles in
the last couple of years about the brain shrinking, etc, during sleep.

A quick search pulled up, for example, this piece:

[https://www.newsweek.com/brain-synapses-shrink-during-
sleep-...](https://www.newsweek.com/brain-synapses-shrink-during-sleep-making-
way-new-information-551871)

~~~
whymauri
One of my favorite papers on the subject, from a colleague's lab:

"Unstable neurons underlie a stable learned behavior"

[https://static1.squarespace.com/static/5859e85dd2b8571a0a859...](https://static1.squarespace.com/static/5859e85dd2b8571a0a859309/t/586c5066e58c624be9ff2165/1483493485348/nn.4405.pdf)

>Motor skills can be maintained for decades, but the biological basis of this
memory persistence remains largely unknown. The zebra finch, for example,
sings a highly stereotyped song that is stable for years, but it is not known
whether the precise neural patterns underlying song are stable or shift from
day to day. Here we demonstrate that the population of projection neurons
coding for song in the premotor nucleus, HVC, change from day to day. The most
dramatic shifts occur over intervals of sleep. In contrast to the transient
participation of excitatory neurons, ensemble measurements dominated by
inhibition persist unchanged even after damage to downstream motor nerves.

Brain circuitry truly is amazing. The connectome is vital to the function of
the brain, and slight perturbations can severely damage that function;
however, the connectome can change over night even in the context of precise
motor skills. It's a sort of Catch-22.

------
vonnik
Tangential but interesting: There's a great Borges short story called Funes
the Memorious, which imagines a man who could never forget anything. To
remember the events of a day, he must spend an entire second day, going
through it second by second.

[https://marom.net.technion.ac.il/files/2016/07/Funes-the-
Mem...](https://marom.net.technion.ac.il/files/2016/07/Funes-the-
Memorious.pdf)

------
digi_owl
Over the years i have come to think that the brain can be better likened to a
de-duplicating storage system, but with some nasty flaws that all too often
result in mixed data on reading.

Meaning that experiences that are similar enough gets overlaid each other,
resulting in time flying past as we get older and to the same stuff day after
day. This because we seem to experience time retroactively.

------
amthewiz
Current neuroscience suggests that brain operates in broadly two regimes -
learning during wakefulness and model selection during sleep. Both these
activities require "forgetting" of specific kinds. Specifically model
selection involves trimming synapses. The goal is to learn a model of the
world at the right level of detail, what AI folks call avoiding over fitting.

------
colemannugent
Memory seems rather like a multi-tier cache hierarchy to me. You can only
really keep something like seven objects in your mind at once, and everything
else seems to be pushed to slower sections of your memory.

Within this analogy cache eviction strategies start to have massive effects on
our ability to process information.

~~~
smallnamespace
There's also the fundamental theory of this which ultimately rests on
thermodynamics, e.g. [1] [2].

Basically, any finite organism only has a finite number of configurations
available to it; but to 'remember' something is to a set up a long-term
correlation between the past and the present, which uses up some of the
'available degrees of freedom' to e.g. respond to shorter-term changes in the
environment.

If you never forget anything, then eventually you 'run out of bits', whereas a
system that allows some forgetting has greater flexibility in e.g. forgetting
the distant past in order to remember to tie your shoes right now.

There are some neuroscientists that are starting to bring thermodynamic views
into looking at actual biological systems as well [3]

[1]
[https://en.wikipedia.org/wiki/Landauer%27s_principle](https://en.wikipedia.org/wiki/Landauer%27s_principle)

[2]
[https://physics.aps.org/articles/v11/49](https://physics.aps.org/articles/v11/49)

[3]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5108784/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5108784/)

------
linkmotif
Micheal Pollan in Botany of Desire has a lot of good stuff about the
importance of forgetting:
[https://books.google.com/books?id=Woywyw8LlcgC&pg=PA162&lpg=...](https://books.google.com/books?id=Woywyw8LlcgC&pg=PA162&lpg=PA162&dq=botany+of+desire+%27For+it+is+only+by+forgetting+that+we+ever+really&source=bl&ots=EMnV0eX6e_&sig=ax7kyOVMzSIAG373IYGxAhYZyC4&hl=ru&sa=X&ved=2ahUKEwjnuKbB-
LjcAhVBdt8KHTiIB7cQ6AEwAnoECAQQAQ#v=onepage&q=botany%20of%20desire%20'For%20it%20is%20only%20by%20forgetting%20that%20we%20ever%20really&f=false)

> For it is only by forgetting that we ever really drop the thread of time and
> approach the experience of living in the present moment.

------
generallyfalse
Don't forget that you are not a fruit fly.

------
IloveHN84
I have probably reach the top of my Remembering capabilities.

Often I feel actively the urge to make free space in my mind to store new
information. Technology helps me keeping offloading useless/unimportant facts
and store them somewhere else, but the overload of information is being an
issue

------
chrstphrhrt
Is that why smoking weed makes things seem profound, from instantly forgetting
the less salient stuff?

------
hanniabu
Well I guess the saying "if you don't use it, you lose it" must be true

------
flabbergast
>> Hardt said. “It filters out the stuff that the brain deems unimportant.”

Most of the things I learned at school I forgot; all the math and so that I
never need in my life. More than half of the curriculum is just rubbish for
our brains IMAO.

Maybe this helps to start making compulsive education more pragmatic. At this
moment I see kids coming from school knowing how to do advance math they'll
never ever need. But basic knowledge about what is healthy food or not, or
knowing how the industry is poisoning almost anything you can buy in the
supermarket, they have no clue.. And I believe knowing those things do matter
for our brain, we would not easily forget.

~~~
kaybe
After I ran my head against math for some time and actually noticed changes to
my mind structure, I am sceptical. Studying math is not (just) about the
knowledge you gain, it is about the reasoning structure behind it, like a
workout for the brain.

Learning things is not (just) about the facts you know afterwards. I read so
many books I forgot at least half of what was written there, but my worldview
and thinking was altered from that.

Not that the other stuff isn't very important too of course..

------
darkerside
This article seems to operate under the premise that photographic memory is
not a thing. Is it considered an urban myth now?

------
euske
So, simply put...

\- short term memory: transaction journal

\- long term memory: persistent table

\- sleep: commit and garbage collection

As I often said, Computer Science can explain everything.

~~~
ralusek
I should hope that it can at least explain your brain, which is a computer.

~~~
lamoutasallite
This is a huge misconception.

------
wahern

      For Robert Calin-Jageman, it’s exciting that forgetting
      seems to be a biological process like digestion or excretion
      because that means it can, at least in theory, be ramped up
      or down.
    

Huh? Of course it's biological. Why would one believe otherwise unless they
made naive deductions from the metaphors du jure--computers and neural
networks. Perhaps the journalist is misinterpreting the researcher, and was,
indeed, working backward from modern metaphors to conclude that it's somehow
novel to think the mechanisms intrinsically corporeal.

~~~
svachalek
I think the keyword here is "process" not "biological"; i.e. that it's an
action taken rather than random decay.

