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Why Am I So Tired When I Get Home?

Written for private circulation, 1997.

Why does sitting in front of a computer make me feel tired?

  • Is it the technology?--maybe the screen resolution is poor, the radiation levels are too high...
  • Is it the ergonomics?--maybe the chair isn't comfortable, the light is wrong, there's no air, I have to strain to use the mouse...
  • Is it the work itself?--maybe the mental strain of the job, the hours, keeping up with bills...
  • Is it me?--maybe I don't get enough sleep, the hangover won't go away fast enough, it was something I ate...

One aspect of the working environment which has often been overlooked is the requirement for you to 'fill in the blanks' of the computer environment. This article explores the extra mental effort needed to translate the 2-dimensional world of the computer screen to the 3-dimensional world of real life.

The 2-D and the 3-D World

Look around you. Think about your desk or table--the area surrounding your computer. Look at your in tray, your filing cabinets and bookshelves, the clutter of day-to-day life. 3-dimensional day-to-day life. Glance at the jotted notes pinned to the wall. Think about the people around you, who you can see and who you can't, how far you would have to go to find the answer to a question.

What are the attributes of your 3-D world? A "natural" prioritization? A sense of everything important being within arm's reach? A very personal tapestry of light and movement, color and shape and texture, patterns, smells and sounds? Possibly a mixture of different organizational schemes suitable to different informational needs.

Now look at your computer screen. A flat piece of glass or plastic. Graphical representations of a desk, filing cabinets, bookshelves, some "tools" that you use. A cluster of "icons" reminding you of what is at your fingertips. If there is a modem attached to the computer, that flat piece of glass becomes a portal to a larger universe, with even more filing cabinets and bookshelves, along with representations of shopping malls and theaters and concert halls and conversation lounges.

The 2-D world also offers light and sound, color and patterns, and even some limited movement, shape and texture. It doesn't do as well with smell, unfortunately. And are the important things easily placed within arm's reach? The third dimension, depth, that we use to find our way and to determine the relationship between multiple objects, can only be approximated through two means:

  1. Graphical representation of shape and size to portray depth
  2. Your memory to remember and recall

It is that second point that contributes to the fatigue brought on by computers. So how does it do this?

Metaphor Soup

In an effort to provide references to the 3-D world, software companies are piling metaphor upon metaphor to help connect users to their tangible tools and experiences. So you 'explore' you 'desktop' for a 'folder' with a 'file' in it (yes, the folder is not the file, the file is in fact the 'document') in order to 'open' the file inside a 'window' (which doesn't let you see through it to other windows or to the desktop on which the window is resting), that is itself contained inside another window which is the 'application' which allows you to 'edit' (create and change) the file, using 'menus' (the window looks into the restaurant, perhaps?) and 'icons' (which themselves need 'tips' to be understandable). All this is accessed using a 'mouse' that 'points'.

I have a headache just thinking about this metaphor soup! Trying to navigate it requires becoming comfortable with a universe of controls and techniques whose definitions are in many ways unrelated to the 3-D world we've grown up learning to explore. It reminds me of Charlie Brown's comment when watching Lucy teach Linus as a child: "he'll have to go to school twice as long as everybody else to unlearn everything she's telling him." The burden of memorizing is the key to "success."

What You See Is Not What You Get

In normal vision, because your two eyes see an image from slightly different angles, the mind merges those two images as the third dimension--depth. It's a miraculous mechanism that relates what you see to the expectations of your memory of physical objects.

Have you ever looked through a camera viewfinder or a telescope? You have to shut one eye and get all your sensory information from the other. The mind fills in the necessary detail based on the balancing of shadow and light, the relative size of the objects, and the memory of the shape of what you are looking at.

Computer graphics designers have come a long way in creating computer imagery that mimics the shapes and textures of 3-D objects--buttons, shadowed boxes, marble-textured backgrounds, all aim to give the illusion of a physical "environment." The goal here is two-fold. First, to create differentiations and accents that help you locate where you are and to separate different screen elements from each other clearly. The second is to help you feel comfortable with the actions of certain screen devices, such as "raising" a button graphically to act as a prompt as to the action of the device, to be "pushed" by a mouse click. In both cases there are clearly successes in the readability of screen information.

But does that create a reality of 3-D? In terms of focal points for the eye, the computer screen is still a flat plane, providing no inherent support for the eye or the brain. It is still required for your memory to make up the third dimension based on experience and expectation with similar objects from the "real" world.

Try this simple test. Look at your computer screen, and get comfortable with the scale of the image. Now shut one eye. Any difference in perception? Now open your eye again. Reach out and slowly move your finger to the screen. Do you have a clear sense of when your finger is about to touch the screen? Now pull your hand away, shut one eye, and move your finger to the screen again. How are you able to determine when your finger is about to touch the screen? By the location? By the size of your fingertip in relationship to the screen objects? Or does your finger, like mine, bump the screen as a way of telling you it has arrived!

So the screen image (2-D) doesn't change, yet your finger's relationship to the screen does. What work is the mind carrying out to maintain adequate use of the screen? Artists have used these techniques for centuries to create enjoyment for the eyes of the observer--but most people rarely stare at those paintings eight hours every day.

Unfortunately, this limitation is not going away (in the near future), so other mechanisms need to be explored to make it easier on the "mind's eye."

Finding Things

Piles develop on your desk over time as a way of grouping similar topics together. The physical closeness or distance of each pile may be a prompt to its urgency or what it contains. The thickness of the pile is a hint to the location of an individual item. The different colors or conditions of the paper (wrinkled, dog-eared) provide visual clues to help locate an item. You can very quickly grab the pile and skim through the pages to locate 'at a glance' an item you may be looking for.

The in tray has an inherent logic to the thickness of the pile. When you want to find something you may often think about when you last attended to that topic. What sort of comments do you mutter to yourself?

It was sometime the week before last...
It was when Alison was in here to discuss that new project...
I put it here just before I left for my vacation in Paris...

The chronological system is not driven by a particular date, but by the way the item is connected by other events in the same time period.

In a book, when you want to find a particular passage, you may begin to locate it by finding the area of the book it is in (about half-way, for example). You may have underlined the passage. The page corner may be turned over, providing a simple visual clue. The visual clue may not be for the passage you want to find, but you know it is 'near' that other passage and that supports your search.

What about finding something in the computer? Admittedly, a full text search in a word processor can be quick and sometimes more fruitful than skimming an article or a book chapter looking for just the right word or phrase. But you need to remember the specific wording of the passage and in many cases how to spell that word. But without that, finding your way becomes more difficult. Did you think in advance about placing some sort of 'bookmark'?

The only chronological mechanism available is to sort by the date of the file, or in rarer cases to remember that you grouped certain files used during a particular time by putting them in one directory/folder. Context in searching for computer-held information is divorced from the real-world context in which the information became memorable.

The challenge is compounded with every step away from the "desktop" toward an external information resource. How do you find documents created by a colleague and left for you on a "server" that holds many people's files? Finding something specific won't be as easy as scanning the papers in his or her out tray. And it gets even more complex as you try to find something on the Internet, where there are a range of expectations about document and image filing, just as there are a range of standards for the software needed to view them once they are found.

Sizing and Scoping a Task

When you pick up a floppy disk, can you tell what is on it? How much content is in a 70k file? Is it all readable text? Are there word processor control codes taking up some of the space, so it may only be 10 pages of text? Is it one picture (equating to 1,000 words, one hopes). Is it a program structure with no content at all? Clues are offered through the name of the file and the name of the application which you must use to view the file, and so you have to carry in your head the relevant memories of each... the computer relies on you.

When you see a document in a word processor, you are given some clues (page numbers, line numbers) that give you an indication of the size of the document and your location. But do those numbers on the screen provide an understandable indicator of the work that faces you? How much time does it take to get a sense of the work that you need to perform? How often do you print a document in order to read and edit it, because it is more comfortable than scrolling up and down on a screen?

3-D media can offer a much clearer sense of the depth and breadth of the task at hand. "When can you edit this document by?" can be answered using some basic rules of thumb given the number of pages, the nature of the content and the experience of the editor. Sometimes this requires a "quick flip through."

The screen window doesn't hold the same context markers, so editors I have seen often print out the materials they are reading. Maybe it is simply an outgrowth of long habit, maybe it is an effect of poor screen resolution, but I believe there is also a component of being able to move quickly through a task because the points of reference and cross-reference are able to be "grasped" at a glance on paper. In computer, the relationships between content elements must be held in personal memory, as there is no way to be tactile with computer memory.

A book has similar attributes that help you use it. The colors and type on the spine, the physical thickness and height of it, help to locate it when it is sitting on a shelf. Pick the book up, and you have an immediate sense of the size of the task of reading it, as you can feel its thickness. It is constantly reminding you as you read of how far you have progressed in the task of finishing the book.

Doing more than one thing at a time

I have to admit that I can walk and chew gum at the same time (though it is not a skill I practice very often). I also tend to do more than one thing at a time when I'm working.

My desk will have papers organized by what I'm working on, all within arm's reach, though some colleagues might not believe that to look at the desk. The people I'm involved with come into view and go out of view as appropriate to the tasks (isn't that supportive of them?).

When working on computer, I prefer to reduce distraction and increase readability by using the full screen to view an application (as with the word processor I'm using now). While this helps make my work on that application more effective, it reduces my ability to "see" the other things I am working on. They don't feel like they are at arm's reach. I tend to have to remember what I have "open" and what state each task is in.

What about looking at which programs are actually running at a particular time? The Microsoft "Start" bar diminishes usefulness as a reminder after about 3-4 programs are open, but remains a useful access device. But isn't it frustrating that the program name or the manufacturer name comes first? At the moment, I have three buttons which all say "Microsoft...". They have icons, which I have to remember how to interpret.

I can use the "Alt-TAB" facility to look at all the programs I have running. However, in order to see more than just the cryptic icons I have to move the focus from one icon to the next, or settle for interpreting the cryptic iconography.

The other way to manage more than one task at a time is not to fill the screen with any single window. The mind is at the mercy of remembering the colors that mean "active" or "inactive" window. Also, the covering, uncovering and moving of windows to see what is in each is either mentally-intensive or mouse-intensive.

Creating something

I want to create something that communicates my ideas to a client. It needs to bring together text, pictures, graphical representations of flows, and numbers. I create a basic document in a word processor, gather and assimilate comments as provided by colleagues over e-mail (unformatted), create my flowcharts and decide the most appropriate format to export them to a file, so they can later be embedded in a document, draw illustrations that I link into the document for presentation purposes (able to be read when presented within a small box, in black-and-white), format the images to be presented through a projector (able to be read when projected on a wall to a large group, in color), and then finally enter, calculate and represent my numbers within the same document.

In order to do the above efficiently, I not only need to know the commands for each of the individual programs, I need to know what is and is not possible when weaving them together and the specific commands to make that happen. I need to remember "tricks" to be sure that the end product meets the expectations of my mind's eye. And I might have to remember actions I haven't done in many months.

The computer carries no understanding or representation of my desired outcome. The outcome remains in my mind until painstakingly constructed using the available tools. Now this is no different than creating a piece of sculpture or a cabinet--I would use a number of tools, each with its own attributes that makes it best for a particular task. But in so many cases with computer software, I'm using very similar tools whose controls are radically different! Imaging having to use five hammers with completely different mechanisms and approaches to use.

Navigating a Space

Much has been written about the inadequacy of the concept of 'browsing' to the more directed task activities related to work. I find it similar to the mental effect of being in a shopping mall--I'm numb from the experience.

The area of web navigation that I think increases fatigue is that of remembering where you are and where you have been. If the old reitorated learning theory has any merit, then the human mind best remembers items of detail in groups of seven plus-or-minus two (5-9)... what happens after the ninth hypertext link to a new location? Do you begin to forget the first one, or work harder mentally to remember them all? How well does the context or topic relationships of the links help the memorization process?

The bookmark function requires that you recognize at the moment of viewing a page that it is something you want to return to. My process of mental "linking" usually means I am looking at something else when I say "aha! This relates to that page I viewed earlier! Now where was it?"

What if you wanted to find something you saw a few days before? In most instances, you have to remember either the address of the location, or the path you took to arrive at the location. The other option is to use a search engine, with the potential for the all-or-nothing bonanza depending on the words you use to describe what you are looking for and the particular software you are using to search.

So in most cases you either have to be vigilant to the value of what you are looking at when you first encounter it, or expect a significant mental effort to be required to find it a second time.


My hope is that by describing the problems in greater detail, industry dialogues and research agendas can begin to form. In that respect, I put forward some possible starting points:

  • Greater consistency of metaphors
  • Multiple filing options based on personal preference and individual meaning
  • Navigational "maps" that reflect personal paths, rather than pre-set structures
  • Some form of context referencing which allows more informal searching for information
  • Question-based search facilities--recent help systems are heading in this direction, but the concept needs to be able to be extended to data as well as pre-determined help/training topics
  • Focus the use of the computer on those things the computer is particularly good at when designing new tasks
  • Assist in the data management and destruction process by providing more details about individual items of data, such as the useful life, the duration of time since last touched, and current status attributes
  • Higher screen resolution to reduce strain and improve the potential for the invention of new graphic mechanisms to reduce mental load.


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Duane Degler 1997-2008