
Ask HN: How much do you remember from books you read only once? - joeclef
I find it difficult to remember much from a book -- technical and non technical -- I read only once, especially when I haven&#x27;t used the knowledge or facts. Is that true for everyone?
======
sytelus
Your brain has a policy of use it or lose it. If what you are reading is
relevant to what you are doing, you would remember it otherwise finer details
would mostly evaporate rather quickly. This is not just about books but for
other things in life too, for example, your past travels or people you meet
day to day. Some people are fortunate to have photographic memory way in to
their 30s but that's rare.

For most things in life, I would suggest using this philosophy: You don't want
to or need to remember everything, rather you want to figure out what insight
you attained from something. For example, after reading a book, writing down
the summery, your opinions and insights at that point would help you more than
remembering every detail. Some people use margin of the book or highlight
passages that they find useful and that's good technique that really works.
Similarly for your travels, instead of writing down every tiny details if you
just maintain logs of surprises and insights you attained each day would be
great way to remember it. Lot of people just go through one book after another
and that's actually significant waste of time as you are not taking time to
digest and reflect on the effort you put in to go through the thing. Writing
things down jogs your memory, forces you to ask questions and brings up the
critical insights that you are otherwise just passing by. In essence, 3 things
helps you the most: write, write and write :).

~~~
ljk
_> For example, after reading a book, writing down the summery, your opinions
and insights at that point would help you more than remembering every detail._

I usually type up notes "on the cloud", what's your opinion on writing up
notes v.s. typing the notes?

~~~
cristianpascu
I find using a computer while reading a book to be very distracting. Or a
phone. I don't like scribbling on a book. I'm hopeless. :)

~~~
ics
See my response below regarding note cards. As an alternative, a twice-folded
sheet of letter size paper may be more available and gives you much more
space. I lay the card down either beside the page I am reading or on the back
cover (you can affix with tape if this makes it easier) depending on the size
of the book.

------
muddyrivers
This happens to me as well. Here is my experience and interpretation.

Before I turned ~20 years old, I was able to remember almost everything from a
book, except exact numbers and foreign names. Along with getting older, I
could remember less and less. However, I feel a good book has greater and
greater influences on me. It makes me think more, gives me more perspective,
makes me realize more how little I know and understand. I paused more often to
think what I just read, instead of just browsing through the book.

This also applies to technical books. Take books on programming languages as
example. When i was young, I could remember most of its syntax after finishing
a book on a new language, and I could jump into writing a program using the
language that could actually be compiled and run. Now, I cannot remember much
about syntax, but I feel I understand more about the new language, in term of
its design, internals, pros and cons, etc. When I am ready to get hands dirty,
I have to keep checking manuals for syntax.

~~~
dpeck
Glad I'm not the only one who feels that way about technical books. I feel
like for me now its much more of a challenge for me to remember how to put my
designs into a language the compiler/runtime for a language understands than
most any other part.

------
Red_Tarsius
One book? Not much. Effective storytelling helps a lot, but only for fiction.

The trick is to read many interrelated books. Same topic, different words.
Those variations on a theme let you quickly uncover the core message behind
authors' styles. The repetition, with slightly different editorial choices,
drills into your mind. _Variations on a theme_ are what makes play so
effective as well.

Take notes in a fixed ritualistic manner. Choose the ONE notebook you'll use;
Write down the most important passages by hand in a slow, precise way. Most
importantly, write a summary of the whole book and FIND CONNECTIONS between
concepts from different books.

I have no scientific paper to show you. I read +-50 books every year and this
is only my personal experience.

------
timdaub
slightly ot, but pg just recently wrote an essay about the issue:

> Reading and experience train your model of the world. And even if you forget
> the experience or what you read, its effect on your model of the world
> persists. Your mind is like a compiled program you've lost the source of. It
> works, but you don't know why.

[http://www.paulgraham.com/know.html](http://www.paulgraham.com/know.html)

~~~
Sealy
Fascinated by that context which leads me to remember what a wise man once
taught me (at a church I used to go to).

He said, "I can't always remember what my wife cooked for me last night,
neither can I last week, or even many of the meals she's lovingly prepared for
me over the last 10 years. However without them, I wouldn't be here today"

Bringing it back to topic, I forget very easily but read quite often. When I
do read, I find it often helps if what I'm reading is of interest to me or at
least inspiring in some way.

~~~
sitkack
A book shapes the mind and allows us to ask more questions, pushes creativity
new directions. Very rarely does one want to just _download_ a book into the
brain. We want to synthesize it, as you say, eat it as food.

------
jseliger
Depends on the book; the average book I remember very little of. But the books
that are great, and that hit me at the right time, I tend to remember more
about, but not enough, so I tend to re-read them.

Re-reading books is underrated.

~~~
curo
Re: re-reading, for me reading a few books on the same or similar subjects
approximates re-reading enough for me to have felt like I've re-read after
only having read.

------
SatvikBeri
Nowadays I use spaced repetition software to capture anything interesting I
see in a book (including insights that occur to me while reading), so I
basically remember everything I want to. Before using SRS I might remember
~20% of a book.

~~~
nyrulez
Which software is this ?

~~~
SatvikBeri
I use ThoughtSaver (www.thoughtsaver.com, currently in very early beta), but
most other people I know who use Spaced Repetition prefer Anki
([http://ankisrs.net/](http://ankisrs.net/)). Gwern has a good introduction to
the general concept of Spaced Reptition:
[http://www.gwern.net/Spaced%20repetition](http://www.gwern.net/Spaced%20repetition)

------
yawaramin
'I've learned that people will forget what you said, people will forget what
you did, but people will never forget how you made them feel.'

~ Maya Angelou

------
rtz12
Mostly everything, I just have trouble accessing it without a lead. But I
can't read a book twice, as I instanty know what happens next.

------
ChuckMcM
Depends on the book, for most of the Science Fiction I read I can recall them
entirely and so re-reading them is not nearly as fun as the initial reading.
My Engineering Calculus book from college? Not so much. Although I still
remember all of the examples from my differential equations textbook. I have
hypothesized in that this is because I tend to reason by analogy and those
examples were examples by analogy so they found fertile ground to land in my
head. Bulk facts? Don't remember. Stories? Almost always remember. And oddly
enough when reading scientific papers I'll often recall the story of what the
investigators were trying find out or how they got there, before I can narrow
it down to the actual result.

As a kid I figured that this was why peoples who didn't have writing passed on
knowledge in stories (easier to remember). But I've never found any support of
that theory one way or the other (at least that I can recall!)

------
techdog
It probably is true, but IMHO it's not "how much you remember" but how you are
changed by what you read.

------
kazinator
A little over two years ago, I answered a related question on the Academia
stack exchange site:

[http://academia.stackexchange.com/questions/7514/what-is-
the...](http://academia.stackexchange.com/questions/7514/what-is-the-best-way-
to-read-a-textbook)

~~~
sitkack
I enjoyed your post. You might like _How to Read a Book_ by Mortimer Adler.

[http://en.wikipedia.org/wiki/How_to_Read_a_Book](http://en.wikipedia.org/wiki/How_to_Read_a_Book)

------
jeffreyrogers
This happens to me as well. I have noticed, however, that while I can't recall
facts very well from books I've read they often do change my perspective on
things and that is much longer lasting. For example, reading the book "The
Selfish Gene" had a profound effect on how I thought about the world, even
though I can't remember much at all of its contents other than it being about
how evolution selects at the level of genes.

With more technical books I find it is almost impossible for me to learn
anything substantial from them unless I do the exercises, however, the
exercises tend to take an enormous amount of time. So what I find myself doing
is skimming most technical books and then then going more in depth on the few
that seem relevant/interesting to me.

------
ne01
I remember almost everything and here is I think why...

I have an ereader which I take to bed at night and I love reading until I pass
out!

It takes me a few nights to finish a book and most of the time the next
morning I practice.

Most of the books are about programming which is a topic that I'm literally in
love with!

------
sonnym
It really depends on the book for me. Technical topics I already know pretty
well, I find easy to commit new methods to memory when I come across them.
Nontechnical, I can remember a good deal of fiction, but factual things fall
off pretty quickly.

I think the most important thing is chunking[1]. You remember key things, such
as storylines or plots from fiction, or, with technical writing, where to
return if you find yourself needing a particular concept in practice.

1\.
[https://en.wikipedia.org/wiki/Chunking_%28psychology%29](https://en.wikipedia.org/wiki/Chunking_%28psychology%29)

------
misiti3780
I am actually developing an iPhone right now with the intentions of solving
this problem. Email me and I can tell you what I am building - maybe you have
some ideas for features that might help: joseph.misiti@gmail.com

------
annie_ab
Well, it's a good thing to ponder on and it's also a pressing issue. In most
of the cases, I only remember those facts and incidents, which have affected
me or appealed to me in a significant way. When I read a book, I can relate to
particular parts based on my life experience, my culture and environment.
Sometimes, longer retention of a book depends on how much the book is awe-
inspiring and the age of the reader. I guess the pressing issue is to learn
and retain relevant things for a longer period of time after reading a book

------
lewisjoe
For me there are two modes with a thin line of difference whilst reading any
book.

In one mode, I tend to have a huge affinity towards either the author of the
book or the potential content of the book. When I happen to read a book in
such a mode, my grasping power works super good and whatever I read on seems
to stay in memory for a longer time.

The other mode is when I come across a resource, that looks potentially
interesting and I'm scanning it to pick up anything that takes me from zero to
one. This is when remembering things takes a little more effort for me.

------
mjklin
Here is my procedure for anyone interested:

* I read all books through audio, with the PDF of the book and the Voice Dream app on iOS.

* I make highlights and notes as I go, then export to a text file when I'm done. So I have the highlights on one hand and the highlighted PDF on the other.

* If I think the notes are important, I will break the text file into individual notes and index them with SCAN and/or dtSearch. I've heard DevonThink is perfect for this, but it's Mac only.

I could probably integrate spaced repetition here, but I haven't explored that
yet. Just my $0.02.

------
Vellin
My brain tends to retain information that it can "see" being played out or
performed. Formulas and equations for example from math textbooks or whatever
have to be focused on and drawn out as if I have a tiny go pro looking down
the end of my pencil at what's being written in my mind as I read the content.
Sounds strange but when I actively make myself retain it this way I can
usually bring it back from my memory very well remembering the "go pro on
pencil video" of the content I need to remember.

------
ddingus
It depends on the book and whether or not I was impacted by it.

Just reading means I will recall something about the book, it's coverage
domains, and maybe some higher level details.

If I work with material in the book, even once, what I remember is
significantly improved.

Impact can be from that, working with material, or it can come from relevance
to things I'm focused on. Sometimes, I read a book, and some parts of it end
up being very relevant and I think about it and make connections.

I recall a lot of this, and do so in detail.

------
saturngirl
Depends on your goal.

1\. If you want to remember a book, so that you can write about it later in
life -> start writing summaries after every chapter you read and a final one
at the end of the book.

2\. If you want to remember details in the book, so that you can talk clearly
about it to someone -> get in the habit of speaking to someone about what you
learned from the book, while you am reading the book. It is best if this is
your significant other or someone who also has interest in the subject.

------
delbel
This concept is sometimes called the Forgetting Curve and is described by an
formula. See
[http://en.wikipedia.org/wiki/Forgetting_curve](http://en.wikipedia.org/wiki/Forgetting_curve)
Also see
[http://en.wikipedia.org/wiki/Spaced_repetition](http://en.wikipedia.org/wiki/Spaced_repetition)

------
notatoad
That entirely depends on the book (but not the subject matter). There's some
books that i read once and am constantly recalling things from, there's other
books that i can read a couple times, feel like i'm understanding or enjoying
it while reading it, and then a couple weeks later i can't remember it at all.
This holds true for me across technical, non-technical, and fiction.

Writing memorably is a skill.

------
randomnumber53
I am a mildly dyslexic. I have excellent reading comprehension, but I read
about a standard deviation slower than the average reader.

Thus, I don't think I've ever read a book "only once," since in order to
understand much of anything, I always end up reading each page paragraph,
sentence, or word until I understand it before I progress.

~~~
zuck9
I find myself doing this too. When I usually read stuff, I understand it on
the first read almost every time but when I'm reading something that I need to
grasp completely like a book or article, I reread the same lines, even in
easily comprehensible novels.

------
Qantourisc
Once had to read a fiction book for school, and write a summary. By the end of
the book I drew a blank, and I had to skim the entire book again.

Technical books are a lot easier to remember, well assuming you are reading
them to learn something (specific ). But that also implies you read something
think about it, make exercises, learn it and THEN move on.

------
joshgel
Consider how you haven't adjusted how you read probably since you were in
grade school. [http://www.farnamstreetblog.com/how-to-read-a-
book/](http://www.farnamstreetblog.com/how-to-read-a-book/)

------
drabiega
I have read a lot of books but only a few more than once. I probably only
remember bits I thought were important from any particular book, but when I
read several on the same subject they tend to overlap in certain parts and I
find I remember those parts very well.

------
vishaldpatel
A well-written book will be easier to remember.

Granted, that one may have to read it again to remember the finer details, but
rarely is a technical book written with the aim engaging the reader in as many
ways as possible.

This is why telling a story is so important. People remember stories.

------
otar
Shameless plug: [https://medium.com/@otar/lifehack-remembering-what-you-
read-...](https://medium.com/@otar/lifehack-remembering-what-you-
read-d8bdb60b7fed)

Lifehack: Remembering What You Read

------
DonGateley
I've a particularly bad case of short term to long term drought. More than
once I've been well into a book or short story before realizing I've read it
before. Occasionally not until I get to the ending.

------
sebkomianos
Not nearly enough and that's why I have decided to actually re-read the books
that I find great; after a certain amount of time though so I can do it with a
(more) "clear" mind.

------
foobarqux
Reading alone, even repeated reading, has been shown to be ineffective in
committing information to long term memory.

You should be able to remember the basic story in a piece of fiction though.

------
elvispt
I find it normal.

Whenever I re-read a book I look at it in a different light or, better yet, I
have a new understanding of the book.

------
ics
I used to be able to remember most of what I read verbatim without any effort.
These days, the harder I try to filter and remember selectively, the worse my
memory gets. What started as a mild compulsion has since become very useful–
taking brief notes as I go on a blank 4x6 notecard. I have stacks and stacks
of them, and every book I start gets a fresh one. Annotating books in the
margins can help you get _into_ it more, but it makes going back much harder
(might as well re-read the book) and pains anyone who likes to keep their
pages scrupulously clean. My "system" is not very strict but mostly follows
these ideas:

    
    
        - Every note begins with a page number unless the same as the previous note
        - Notes are separated by a /
        - Underline names/places/any *thing* to look up later
        - Mark very important notes with a star or border
        - Copying chapter titles sometimes helps
        - Copy quotes, quick references (to other works), typos
          (not really necessary, but "Statute of Liberty"...), or
          thoughts & tangents. Typically I just write down a few
          words here and there and then write about them
          elsewhere (on the computer or in my notebook)
        - At the very end, include a brief summary of what I felt
          like or knew about before reading, while reading, and
          after reading. I only find this useful for bios,
          letters, theses, and that sort of thing.
    

I can: re-read my notes and it will come back, skim notes to narrow down a
page range for a detail that I'm looking for, scan the notecards for reference
anywhere, keep my notes for library books, etc. That being said, I don't
really recommend it to people. If you write slowly, large, or don't like
keeping a pen/pencil on hand then it can be annoying.

Aside: I've considered automatically putting these notes into Anki after OCR
(the one shown is a messy example, it seems to work though) but I think that's
touching a matter apart from the top poster's intention. Rote memorization is
useful, but the simple act of writing stuff down by hand has its own benefits
without requiring much involvement.

Another thing to point out is that _what_ you read is just as important. The
reason I care about extracting references to other works, even if I can't read
them immediately, is because it cements a topic in your mind rather than just
being another cloud of words and hazy memories. Today I read _Species of
Spaces_ (Georges Perec) and on one page he references Forbidden Planet because
of the large triangular doors. I made a note of it since I don't actually know
what he's talking about (born in the '90s, didn't have TV, didn't see
Forbidden Planet, don't blame me). Mentioning it here might actually be enough
to make it stick, but I still intend to either read up on the film or, if I
have the time, watch it (but not just for that scene!).

Example:
[https://dl.dropboxusercontent.com/u/28629850/Condit%2C%20Car...](https://dl.dropboxusercontent.com/u/28629850/Condit%2C%20Carl%20W.%20-%20American%20Building%20%281%29.png)
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