10 ms·

Four Hours of Concentration

334 points by wmat 14y ago

drcode 14y ago
...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.
stephengillie 14y ago
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 14y ago
  Sounds quite similar to the concept of ego depletion : http://en.m.wikipedia.org/wiki/Ego_depletion http://en.m.wikipedia.org/wiki/Ego_depletion
  - ErikAugust 14y ago
    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.
- rayiner 14y ago
  I think theoretically less-intense tasks use up your concentration more quickly if you do it intermittently with an intense task. Which I think makes the usual "work 30 minutes, Facebook 5 minutes, repeat" cycle quite devastating to productivity. I think we overestimate how quickly we can really context switch. It's interesting to look at how people respond to stimulants. People take adderall to "help them focus" but what it really does is magnify what I think is a latent resistance to context switching.
- jonmc12 14y ago
  In 'How to Create a Mind', Kurzweil states that Kasparov could simulate 100k board positions in parallel. Which was roughly same working knowledge as, say, Shakespeare with 100k word senses (http://books.google.com/books?id=FCcXiBPurdEC http://books.google.com/books?id=FCcXiBPurdEC - search for 'board positions' and read next 3 pages). Further, he suggests that each of the 100k may require 100 pattern recognizers in neo-cortex. That means, the brain needs to configure 10 million patterns in total - these are either newly observed, or new relations formed with existing patterns. I'm sure its not linear, but if you divide 10M patterns by 10k hours, that means the neocortex needs to add an average of 1 pattern every 3.6s, or 4k patterns per every 4 hours (ie, limit for day). Thats about 400k neurons / day re-purposed for learning through deliberate practice to learn 40 board positions / day in chess. __________________________ Continuing the conjecture, what we know about about spaced-repetition and mass-repetition might provide some nice bounds for upper limit on how these neurons can be exposed to learning material over 4-hr period to optimize their use as pattern recognizers. Could make a nice illustrative simulation to speculatively address your question about limits of concentration / learning reservoir.
flexie 14y ago
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 14y ago
  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 14y ago
    > 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 14y ago
      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.
mattm 14y ago
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.
idoh 14y ago
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 14y ago
  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.
droithomme 14y ago
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 14y ago
  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 14y ago
    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?
Gobitron 14y ago
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 14y ago
  I've read a couple of Tony Schwartz's books which go into this topic more and helped me to rethink my working habits.
- deleted 14y ago
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ojbyrne 14y ago
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 14y ago
  Incidentally, would the 2 hours of concentration take place at home? See: http://dilbert.com/strips/comic/1995-09-15/?CmtOrder=Rating&CmtDir=DESC http://dilbert.com/strips/comic/1995-09-15/?CmtOrder=Rating&...
  - rdtsc 14y ago
    No joke. Sometime the only time I get un-interrupted stretch of 2-3 hours is at home, at night.
    - VinzO 14y ago
      Same for me, once my wife and kid are asleep
- nandemo 14y ago
  Wow, 2 hours of concentrated work in the morning sounds exceptional to me. With open plan offices -- the norm in Brazil and Japan -- it's damn near impossible to have 20 straight minutes of uninterrupted work: phones ringing, people talking to each other from afar, people interrupting you, etc.
johnfuller 14y ago
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.
mappum 14y ago
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).
rthomas6 14y ago
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 14y ago
  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 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).
- dyno12345 14y ago
  There are lots of studies that show this actually http://www.uvm.edu/~pdodds/files/papers/others/everything/ericsson2007a.pdf http://www.uvm.edu/~pdodds/files/papers/others/everything/er...
adamnemecek 14y ago
I believe that the 37signals guys have a very similar opinion.
mercuryrising 14y ago
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 14y ago
  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."
cerebrum 14y ago
Another good argument for working from home as opposed to a corporate environment.
incision 14y ago
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 http://en.wikipedia.org/wiki/Pomodoro_Technique
Dove 14y ago
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.
ErikAugust 14y ago
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.
deleted 14y ago
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artursapek 14y ago
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 14y ago
  Gladwell is a poor example.
  - artursapek 14y ago
    Why, because he bullshits? I'm not citing him as a scientific authority but he certainly is a prolific author.
sepetoner 14y ago
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.
johnfuller 14y ago
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.
wiradikusuma 14y ago
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 14y ago
  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.
axiom 14y ago
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.
- Smudge 14y ago
  I'd be shocked if those 12-16 hours you apparently put in for "weeks on end" are truly your most productive. They may certainly feel "mentally strenuous," but that doesn't mean your cognitive limit isn't decreasing as the days and weeks go on. I find that I can focus intensely for shorter bursts over a couple hours, but then I hit my limit and need to push the really hard stuff aside for a while. Sure, I can crank through a ton of tedious or menial tasks (and there are certainly plenty of them), but that's really not the same. When I complain about being expected to sit around for 8, 9, 10 hours a day (and I do occasionally complain), it's not because I'm rationalizing lazy habits or want to get out of work. I love my work. No -- It's because in only 3-4 of those hours I will finish 90% of what I ultimately get done in a day. The trick is in knowing how to optimize those hours of productivity, and when to go home and give your brain time to decompress.
- zasz 14y ago
  I'm sure you're working hard on demanding things, but a world-class violinist is probably doing something much, much harder than you are. Even if you don't respect violinists, surely you have to respect that an expert mathematician trying to make a new discovery is working on problems much harder than anyone in the corporate world. So I don't think this article applies to you, or other people working long hours either, or to people who should be working long hours.
- jdietrich 14y ago
  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.
realitygrill 14y ago
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 14y ago
  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.)
s4sagar 14y ago
Pointless to quantify the amount of time until "Concentration" can be quantified.
whiddershins 14y ago
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.
deleted 14y ago
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levlandau 14y ago
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.
coffeeaddicted 14y ago
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 14y ago
  Coffee.
galaktor 14y ago
Relevant read: http://www.your-brain-at-work.com/ 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.
cvursache 14y ago
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 14y ago
  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 14y ago
    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.
- a3voices 14y ago
  http://projects.ict.usc.edu/itw/gel/EricssonDeliberatePracticePR93.pdf http://projects.ict.usc.edu/itw/gel/EricssonDeliberatePracti...

334 points by wmat 14y ago

...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.

stephengillie 14y ago

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 14y ago
Sounds quite similar to the concept of ego depletion : http://en.m.wikipedia.org/wiki/Ego_depletion http://en.m.wikipedia.org/wiki/Ego_depletion
- ErikAugust 14y ago
  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.
rayiner 14y ago
I think theoretically less-intense tasks use up your concentration more quickly if you do it intermittently with an intense task. Which I think makes the usual "work 30 minutes, Facebook 5 minutes, repeat" cycle quite devastating to productivity. I think we overestimate how quickly we can really context switch. It's interesting to look at how people respond to stimulants. People take adderall to "help them focus" but what it really does is magnify what I think is a latent resistance to context switching.
jonmc12 14y ago
In 'How to Create a Mind', Kurzweil states that Kasparov could simulate 100k board positions in parallel. Which was roughly same working knowledge as, say, Shakespeare with 100k word senses (http://books.google.com/books?id=FCcXiBPurdEC http://books.google.com/books?id=FCcXiBPurdEC - search for 'board positions' and read next 3 pages). Further, he suggests that each of the 100k may require 100 pattern recognizers in neo-cortex. That means, the brain needs to configure 10 million patterns in total - these are either newly observed, or new relations formed with existing patterns. I'm sure its not linear, but if you divide 10M patterns by 10k hours, that means the neocortex needs to add an average of 1 pattern every 3.6s, or 4k patterns per every 4 hours (ie, limit for day). Thats about 400k neurons / day re-purposed for learning through deliberate practice to learn 40 board positions / day in chess. __________________________ Continuing the conjecture, what we know about about spaced-repetition and mass-repetition might provide some nice bounds for upper limit on how these neurons can be exposed to learning material over 4-hr period to optimize their use as pattern recognizers. Could make a nice illustrative simulation to speculatively address your question about limits of concentration / learning reservoir.

flexie 14y ago

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 14y ago
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 14y ago
  > 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 14y ago
    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.

mattm 14y ago

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.

idoh 14y ago

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 14y ago
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.

droithomme 14y ago

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 14y ago
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 14y ago
  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?

Gobitron 14y ago

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 14y ago
I've read a couple of Tony Schwartz's books which go into this topic more and helped me to rethink my working habits.
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ojbyrne 14y ago

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 14y ago
Incidentally, would the 2 hours of concentration take place at home? See: http://dilbert.com/strips/comic/1995-09-15/?CmtOrder=Rating&CmtDir=DESC http://dilbert.com/strips/comic/1995-09-15/?CmtOrder=Rating&...
- rdtsc 14y ago
  No joke. Sometime the only time I get un-interrupted stretch of 2-3 hours is at home, at night.
  - VinzO 14y ago
    Same for me, once my wife and kid are asleep
nandemo 14y ago
Wow, 2 hours of concentrated work in the morning sounds exceptional to me. With open plan offices -- the norm in Brazil and Japan -- it's damn near impossible to have 20 straight minutes of uninterrupted work: phones ringing, people talking to each other from afar, people interrupting you, etc.

johnfuller 14y ago

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.

mappum 14y ago

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).

rthomas6 14y ago

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 14y ago
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 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).
dyno12345 14y ago
There are lots of studies that show this actually http://www.uvm.edu/~pdodds/files/papers/others/everything/ericsson2007a.pdf http://www.uvm.edu/~pdodds/files/papers/others/everything/er...

adamnemecek 14y ago

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

mercuryrising 14y ago

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 14y ago
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."

cerebrum 14y ago

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

incision 14y ago

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 http://en.wikipedia.org/wiki/Pomodoro_Technique

Dove 14y ago

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.

ErikAugust 14y ago

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.

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artursapek 14y ago

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 14y ago
Gladwell is a poor example.
- artursapek 14y ago
  Why, because he bullshits? I'm not citing him as a scientific authority but he certainly is a prolific author.

sepetoner 14y ago

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.

johnfuller 14y ago

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.

wiradikusuma 14y ago

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 14y ago
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.

axiom 14y ago

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.

Smudge 14y ago
I'd be shocked if those 12-16 hours you apparently put in for "weeks on end" are truly your most productive. They may certainly feel "mentally strenuous," but that doesn't mean your cognitive limit isn't decreasing as the days and weeks go on. I find that I can focus intensely for shorter bursts over a couple hours, but then I hit my limit and need to push the really hard stuff aside for a while. Sure, I can crank through a ton of tedious or menial tasks (and there are certainly plenty of them), but that's really not the same. When I complain about being expected to sit around for 8, 9, 10 hours a day (and I do occasionally complain), it's not because I'm rationalizing lazy habits or want to get out of work. I love my work. No -- It's because in only 3-4 of those hours I will finish 90% of what I ultimately get done in a day. The trick is in knowing how to optimize those hours of productivity, and when to go home and give your brain time to decompress.
zasz 14y ago
I'm sure you're working hard on demanding things, but a world-class violinist is probably doing something much, much harder than you are. Even if you don't respect violinists, surely you have to respect that an expert mathematician trying to make a new discovery is working on problems much harder than anyone in the corporate world. So I don't think this article applies to you, or other people working long hours either, or to people who should be working long hours.
jdietrich 14y ago
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.

realitygrill 14y ago

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 14y ago
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.)

s4sagar 14y ago

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

whiddershins 14y ago

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.

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levlandau 14y ago

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.

coffeeaddicted 14y ago

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 14y ago
Coffee.

galaktor 14y ago

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

cvursache 14y ago

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 14y ago
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 14y ago
  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.
a3voices 14y ago
http://projects.ict.usc.edu/itw/gel/EricssonDeliberatePracticePR93.pdf http://projects.ict.usc.edu/itw/gel/EricssonDeliberatePracti...