
Four Hours of Concentration - wmat
http://www.johndcook.com/blog/2013/02/04/four-hours-of-concentration/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+TheEndeavour+%28The+Endeavour%29
======
axiom
Unbelievable, 40+ comments and not one contrary opinion.

Alright, I'll be that guy. I have no trouble doing more than 4 hours worth of
mentally strenuous work in a day, and neither do most of the people I work
with. Frequently enough I've put in sustained 12-16 hour days for weeks on end
to meet a tough deadline.

You'll generally find that the most successful people who are best at what
they do have no trouble with this either. I'll go further and say that a large
number of the people who complain about having to work more than a few hours a
day are doing nothing more than rationalizing their lazy HN and/or reddit
habits.

~~~
jdietrich
I think you define "strenuous" quite weakly. The overwhelming majority of jobs
don't require very much cognitive effort, even in software. Most developers
hardly ever actually do anything legitimately hard in their day-to-day work.

Proving theorems is a completely different class of work to chipping away at
your failed unit tests or knocking together a CRUD app in your favourite
language. Maybe a tenth of one percent of software developers routinely do
work that is intellectually on a par with mathematical research; The rest are
for the most part skilled tradesmen, doing work they understand relatively
well.

It is universally accepted that all but the most prodigious musicians do not
benefit from more than 4 or 5 hours of practice a day. They can often easily
_do_ twelve or sixteen hours a day, but the extra time is simply wasted. Once
your reserves of concentration are spent, you're just going through the
motions without learning anything. Most conservatories go to great lengths to
persuade their students to practice less, because young musicians are often
convinced that they can attain mastery through sheer force of effort.

I can sit and transcribe or arrange parts all day long. I can play from sheet
music until my hands give out, all the while daydreaming about what I'm having
for tea or what chores need doing. I can't usefully improvise or compose for
more than about two hours at a time, or more than four hours in a day. I can
feel the point at which I start playing familiar riffs rather than truly
improvising; When I've run out of ideas and I'm just writing pastiche. There
are composers who claim to do regular eight-hour days, but when you look
deeper they invariably spend most of that day arranging or transcribing or
recording into the computer, stuff that's essentially just admin.

~~~
SilasX
>Most developers hardly ever actually do anything legitimately hard in their
day-to-day work.

I might agree with that in an absolute sense. But if we're going to talk about
percentiles, and relative to the human population, very few people
(percentage-wise) can even do the "easy, boring" part of programming you're
referring to.

~~~
Detrus
It is hard to learn. But once you learn it, not that hard to do CRUD day to
day. When you have to learn some new framework/library it gets harder again.

~~~
robertk
Well, as a mathematician, I can say the same is true of mathematical research.
Climbing Mount Bourbaki is a difficult endeavour, but from the top the
pastures are relatively peaceful to explore. Most papers are not
groundbreaking theoretical sledgehammers, but minor updates on footnotes of a
vaster theory.

~~~
SilasX
This matches my experience about technical, "it's complicated" knowledge in
general: the hard part is catching up to what everyone knows, but once there,
contributing and improving are surprisingly easy and obvious.

Just recently I was given a task of debugging a major problem with our website
that was causing frequent emergencies -- and apparently, was mystifying the
developers.

My lead realized I'd need to understand the website's infrastructure first, so
he took about 45 minutes explaining how it all fit together and where the
problem occurred. But once I got to that point, my reaction was, "Wait --
wouldn't the problem go away if you just ... _didn't_ do $STEP at that point?"

Turned out to be the entire solution to the problem.

------
mercuryrising
I don't intentionally try to structure when/where/how I think about things,
but after 23 years, I've gotten pretty in tune with knowing how things 'feel'
inside.

I know if I'm going to have a shitty day or a great day the moment I wake up,
the first interaction I have with a person (knowing this may make it more
likely to happen, but short of that...).

I know when my brain is running on all cylinders, and when it's choking for
more air. Tuning into these signals (I have no idea what they are, only
'feelings'), I can lay out the things I want to do in the next few days, and
roll with the punches. It'd be interesting to see the amount of time idlers
and time progressors (I'm at my computer most of the day, looking at my google
search history would give a good indication - I generally don't google that
much when I read articles on HN or Reddit, but when I'm doing something I'm
googling up a storm).

No sense fitting a square key into a round hole when tomorrow the round key
will be sitting in my hand.

~~~
the_cat_kittles
You have to be careful not to give too much weight to something that can have
self fulfilling prophecy effects- i.e. "I'm going to have a shitty day" sets
you up to have a shitty day. I'm not saying its bad to listen to your internal
compass, but you have to make sure that you aren't just giving yourself
excuses. In my experience, I found that sometimes I have done exactly that,
like I have something difficult to do and all of a sudden "my mind is tired,
now isn't a good time."

------
ojbyrne
In my experience this is what happens with programmers in corporate
environments and produces excessive hours - 2 hours concentrating in the
morning, 2 hours concentrating in the evening, and 8 hours of bullshit in
between.

~~~
LearnYouALisp
Incidentally, would the 2 hours of concentration take place at home? See:
[http://dilbert.com/strips/comic/1995-09-15/?CmtOrder=Rating&...](http://dilbert.com/strips/comic/1995-09-15/?CmtOrder=Rating&CmtDir=DESC)

~~~
rdtsc
No joke. Sometime the only time I get un-interrupted stretch of 2-3 hours is
at home, at night.

~~~
VinzO
Same for me, once my wife and kid are asleep

------
droithomme
Back in the old days when I was in school, I didn't do well with more than 3
classes in a row in college. Not just me though, nearly everyone started with
2 Tu-Th 1.5 hr classes and 2 M-W-F 1 hr classes. That was a full time 12 unit
load, but I always took at least 16 units, and sometimes as many as 24, which
was up to 3 more classes a week. 16 units was a full time job, the semesters I
took 20 and 24 were very special cases where some of the classes were subjects
I already knew well or were research project based classes. I think 16 is a
good solid load for the typical college student.

When I'm really refreshed and interested and doing well and eating right I can
pull all nighters and maintain work quality. I can't maintain this for
extended stretches at all though.

For a sustained pace though, I agree completely with Mr. Cook and his sources
that 4 solid hours a day is about right.

There are many people who put in substantially more hours and brag about it. A
close look though nearly always reveals lots of meetings, busy work, and -
these days - surfing the net, playing games, and flirting or shooting the
breeze with coworkers. Remove all that and you seldom see more than 4 hours,
and almost never 4 hours of solid work sustained for months at a time.

We should also consider whether this discussion is relevant to calls to extend
school hours to 7 or 8 or more hours a day in the primary school classroom, as
many are calling for. Does Finland, which has fewer school hours than the US,
have better results because of it?

~~~
solarmist
Most of that work isn't that cognitively demanding though. If you're reading
research papers or textbooks most of the time the really hard parts have been
done for you. You just need to follow along.

Also, with most work there's lots of things that need to do that require
relatively little concentration once you've made the cognitive shift.

I think the four hour limit applies to design/creative work or work that
requires immense attention to detail.

I'd say most people have little in a day that actively drains this reserve in
more than a trickle.

~~~
jules
If reading research papers is not cognitively demanding, that just means that
you're not reading fast enough, or you're not truly absorbing the content. Or
are you saying that the speed at which you read research papers is limited by
the speed at which your eyes can move?

~~~
solarmist
I meant it relative to writing them.

~~~
seanmcdirmid
Reading can be harder than writing, especially if the writing is very bad and
you must understand!

------
idoh
I'm a proponent of this theory, and it worked for me in Law School. I would
only study for two two hour sessions each day, after which I was free to do
whatever I wanted. This worked quite well for me, and I always felt fresh and
sharp, especially when finals came around.

I also did the same study plan for the bar exam and feel like it worked well
there too, i.e. passed it on the first try with a minimum of drama, the whole
thing was actually quite pleasant.

In contrast, many of my peers would study basically around the clock, pull all
nighters, made their lives miserable and didn't do any better, and more often
than not quite worse.

~~~
rayiner
I tend to agree, although I think you can concentrate longer for short,
unsustainable durations. My standard schedule in law school was a few hours
during the semester, then a few weeks of 8-10 hour days around finals.

My take away from the experience was that 8 hours of real work is really a lot
of work. And distractions are absolute poison: internet, cell phone, etc.
Nothing quite like locking yourself in a room with just a book and highlighter
--no computer, no cell phone, no people. You add those things to the mix and
it can easily take a 16 hour day to get 8 hours of real work done.

------
rthomas6
Are there any peer-reviewed studies on this? This looks like purely anecdotal
evidence. It makes sense on the surface, but I don't think I can trust that
four hours of intense concentration per day is some sort of "cognitive limit"
without an actual scientific study.

~~~
gwern
I don't know about writers and the morning, but there is plenty of evidence
that the ideal block of learning or studying is pretty small. For example, you
have spaced repetition ( <http://www.gwern.net/Spaced%20repetition> ), where a
few short minutes of studying spread out over time is vastly more efficient
than a few big blocks of studying with no subsequent review sessions. And I
believe there's a bunch of research on lectures becoming a waste of time after
around 15-20 minutes (IIRC, FAA-sponsored).

------
johnfuller
I think another item to add to this is that some days that 4 hour day is going
to be your ceiling and anything which creates yet more cognitive exhaustion is
going to erode that further. For example, serious stress from having to hit a
deadline or being overloaded could bust that 4 hours worth of reserves down to
2 or 3. If you try to force it, you might just end up sitting at your
workstation all day idling at brainless tasks such as browsing the internet or
half attempting to create some sort of structure out of the mess of the task
list your clients have sent you.

It's interesting that we see so many articles posted on hacker news on how to
be more productive, beat procrastination and be more motivated when really
this article the OP posted explains it all. In most cases you probably don't
have a problem with procrastination and motivation, it's simply that you are
over-extending yourself. Cut back your commitments and you fix your problem.

------
johnfuller
I have been freelancing for most of my time as a developer, and I have worked
remotely for all of it.

The one actual job I had as a web developer set the work week as 40 hours a
week (8 hours a day.) This left me wondering if any developers actually work
this long of a day and how they could possibly do it.

When I'm doing client work, I'm ON, all the circuit boards are lit up. I can't
keep this going for more than 4 - 6 hours per day. If I work a long day, then
the next day I'm drained and I have to pay off that debt.

It actually took me years to really figure this out after a life of being
trained to the 40 hour work week (parents, my early work life.) The 40 hour
model for work is broken.

------
stephengillie
If you practice something 4 hours per day, 365 days per year, you'll hit the
legendary 10,000 hour mark in about 6 years and 10 months.

\---

Does this mean that each of us has a reservoir of about 4 hours of intense
concentration per day? When we perform a less-intense task, like driving or
facebooking, are we using those 4 hours at a reduced rate?

This sounds like it could feed into another idea - that each human has a
limited number of actions per day. Performing actions costs concentration, and
so we pay for each action from our concentration reservoir?

~~~
minikomi
Sounds quite similar to the concept of ego depletion :
<http://en.m.wikipedia.org/wiki/Ego_depletion>

~~~
ErikAugust
Agree - Daniel Kahneman's Thinking Fast & Slow is a good book that addresses
the topic. Understanding how the brain works a bit really helped me to get "in
the zone" a lot more often and I have certainly seen gains in
focus/concentration (which translates into learning/ability) because of it.

------
flexie
That's what I have always said about law. I can do about 4 hours of legal work
a day. Then I am absolutely done. I have no idea how my colleagues can clock
in 8 hours.

Yes - there are days I can do more. But there are also days I do less than 4
hours. In the long run I do about 4 hours a day. That's it.

~~~
stephengillie
Your colleagues likely work 4 like you, then bill for 8. Scott Adams (maker of
Dilbert) once said this is extremely common in the corporate world, and my
experience largely agrees. Much of the other 4 hours may be spent in meetings,
lunches, relocating, gossiping, or internet browsing. You're largely paid to
be on-site and aware for 40 hours a week, not to necessarily produce anything.

One of Adams' books has a story about someone who took 2 simultaneous jobs at
one company. He would show up early on one floor, then take an early lunch and
head upstairs to his other job, where they thought he was just arriving late.
The employer did eventually catch on, but until then he was paid 16 hours of
work for 8 hours of his time.

~~~
mattm
> You're largely paid to be on-site and aware for 40 hours a week, not to
> necessarily produce anything

This really bugged me early on in my career before I understood this. When I
started work I would feel disappointed that I couldn't be productive for 8
hours per day. Then I realised that no one else around me was getting probably
more than 3 hours of work done in a day so I set my aim for each day at 4
hours of productivity and used a timer to track my concentration time.

I still feel conflicted by it though. When I was freelancing, I tried doubling
my rate with the expectation that I would only work 20 hours per week. I think
most people thought I was lazy and wouldn't go for it. Hopefully in the future
we'll be able to move away from the idea that a 40+ hour work week is ideal.

~~~
analog
You have to frame your rate in terms that demonstrate the value you'll be
providing.

Eg you could say you'll only be working 20 _billable_ hours per week and
suddenly it sounds like they will be getting some of your time for free.

The rest of the time is actually taken up with marketing, administration,
training etc.

~~~
stephengillie
Don't forget that some clients value face time. Sometimes I wonder if a client
is just paying me to be around him...

~~~
vidarh
I did contracting for some short stints when I was younger, and quickly
realised that this was it.

I could quote a fixed price for some work, and they'd readily accept my rates.
But if I then would try to leave after the amount of time the work actually
took me, they'd question whether or not I was actually doing the job properly.

So I quoted even higher on the expectation that 1) I'd have to sit in a chair
in their office 8 hours a day and so couldn't do other work elsewhere and
needed to be compensated extra for that inconvenience, 2) I'd be bored out of
my mind trying to fill the rest of the time I was there.

Never a question raised.

It was frustrating. Especially one job where I as stuck for 3 weeks on a
machine with no internet connection doing a job I could easily finish with 2
hours every day. Whenever possible I'd work remotely.

------
coffeeaddicted
Do we have any idea what it actually _is_ what is getting depleted when we
start to run out of energy or concentration? It's something I've wondered
about already a few times - I mean I can pretty much feel running out of steam
myself. Which means there is some way in which my mind is able to measure
whatever it is that it causing this.

~~~
tasuki
Coffee.

------
Gobitron
By and large I agree with this, but I think there is another element to
consider, which is your overall energy levels. If you exercise, eat right,
laugh, spend time with family and friends, then you're more likely to be able
to consistently put in this kind of effort. I don't think you can or should
aim to do much more than 4, but I think a very large proportion of the world
isn't capable of even coming close to 4, because they don't or can't manage
their energy effectively.

I also agree it is possible to do longer bursts, but that is pretty rare in my
experience.

~~~
mattm
I've read a couple of Tony Schwartz's books which go into this topic more and
helped me to rethink my working habits.

------
drcode
...of course, most people (including myself) may be incapable of the intense
concentration that a genius like Poincaré could muster. Therefore, it's hard
to know how useful this fact is to a typical person.

------
ErikAugust
Implications: People are not going to be great at their second job or at night
school. It's probably better to quit a tiring job and find a quiet one where
you can study something you want to do with your life.

------
incision
I've have great success with something similar to The Pomodoro Technique.
Alternating activities every few segments helps me go a lot longer than I
would trying to plow through on one subject.

1: <http://en.wikipedia.org/wiki/Pomodoro_Technique>

------
galaktor
Relevant read: <http://www.your-brain-at-work.com/>

"Your Brain At Work" points out, among other things, that the brain is capable
of doing much less intensive work (as in, concentration) than most people
believe it is.

------
Dove
Oh, it can be done. Just not every day. I once went on a hacking run in grad
school that was over 24 hours sustained. I was a gibbering mess for the next
couple days, but I think it was worth it.

I wouldn't do it for a job, though. I think that can only be done for love.

------
realitygrill
I first read about the ~4 hour limit from D.E. Littlewood's book, Littlewood's
Miscellany. He recommends "four hours a day or at most five, with breaks about
every hour (for walks perhaps)."

Since then I've read of luminaries mentioning this in passing, but I haven't
really tried to employ it. (I'm also pretty sure I've seen pg say this is
empirically false with YC founders, and perhaps he and axiom are correct)

I'd like to know if there's evidence of this for _learning_ , however, even if
it is mathematics.

~~~
hyperbovine
Littlewood was a talented mathematician; pg is an employer of computer
programmers. Unless you are doing original research, which, AFAIK, most YC
companies aren't, I see no reason why you should limit yourself to 4 hours a
day. (Apart from having a life, but that's a separate debate.)

------
cerebrum
Another good argument for working from home as opposed to a corporate
environment.

------
cvursache
Even though a lot of smart people agree that we can only get a few hours of
real concentration a day, not many of them link to scientific papers that
support this claim. I would agree that the claim "feels right". But in absence
of a real experiment, how valuable is this insight really? Maybe useful to
keep the idea in the back of one's head, but seems far from a definitive
answer.

~~~
johndcook
I imagine that any feasible scientific experiment would measure only a crude
approximation to reality. How can you randomize someone to a job and a way of
working? Most people are not capable of concentrating for four hours a day, or
have jobs that don't permit it.

At best you might recruit some undergraduates -- nearly all psychology
subjects are college students -- and have them do some artificial task one way
or another for a couple weeks. I find anecdotes from successful musicians,
scientists, and authors more persuasive than data from an contrived scientific
study.

~~~
cvursache
Those are good points and I agree with everything you said. And even though
anecdotes are informative, they may not be enough to make big important claims
about how people should manage their mental energy.

------
whiddershins
I have worked with some extremely successful and famous artists and musicians,
some follow the pattern outlined here, some do not. I know one musician who
would work for 36 or 48 hours or more without a break of any kind including
sleep, so as to complete an idea without losing the thread. The proof is in
the pudding and there are many many recipes.

------
mattm
This echoes my experience as well, however I prefer to break it into 3 x 80
minute blocks. The times when I've tried to push myself beyond that for a
short period of time (a few weeks) I have ended up sick, ill or entirely
unproductive to make up for it.

------
mappum
This is reassuring for me. On a normal day, I only really do so much actual
coding and intense thinking, and I usually wrongfully compare it to the crazy
energy drink fueled all-nighters (which makes me feel like I'm not getting
enough done).

------
levlandau
There's a difference between being maximally productive at any given time and
coming out cumulatively ahead. The strong claim is to state that one is always
net less productive when working sub-optimally at any given time. I doubt that
this is true but i suppose it depends on how quickly productivity falls off
with strain. I suspect that it's probably ok to work long hours to get through
repetitive learning but its best to reserve a fresh focus for your more
creative moments.

------
sepetoner
I spent ~7 hours a day when I was learning C++. I basically had to do this in
order to be able to take my course the next semester in college. I went from
knowing absolutely nothing about programming, to having a very firm grasp on
the subject, and actually being one of the best in my class.

I would have learned a lot with 4 hours a day, but I think the extra 90 hours
I put in that month really helped me out.

------
artursapek
Malcolm Gladwell said in an on-stage interview I witnessed that he can only
write for two to three hours a day. The rest of his time he spends doing less
demanding work like research and setting up interviews with people.

From what I've seen, most employed programmers only spend about this much time
(maybe a bit more) actually programming.

~~~
vertr
Gladwell is a poor example.

~~~
artursapek
Why, because he bullshits? I'm not citing him as a scientific authority but he
certainly is a prolific author.

------
wiradikusuma
Pure curiosity from the perspective of life hacking: Does this mean we can
have e.g. 3 tasks parallel in a day where 3x4hours = 12 hours? Say you want to
write high quality code, mastering piano and write symphony at the same day,
until you reach 10k hour each (=mastery).

~~~
rwallace
No. But it does mean you can do two tasks in a day if one of them doesn't
require a lot of concentration or mental effort, e.g. four hours programming
and four hours gardening.

------
s4sagar
Pointless to quantify the amount of time until "Concentration" can be
quantified.

------
adamnemecek
I believe that the 37signals guys have a very similar opinion.

