Design of Everyday Things [56]
• What parts of the object are supporting surfaces? How much size and weight will the object support?
The same kinds of questions arise whether we are trying to decide what to do or attempting to evaluate the results of an action. In examining the object, we have to decide which parts signify the state of the object and which are solely decorative, or nonfunctional, or part of the background or supports. What things change? What has changed over the previous state? Where should we be watching or listening to detect any changes? The important things to watch should be visible and clearly marked; the results of any action should be immediately apparent.
MAKING VISIBLE THE INVISIBLE
The principle of visibility is violated over and over again in everyday things. In numerous designs crucial parts are carefully hidden away. Handles on cabinets distract from some design aesthetics, and so they are deliberately made invisible or left out. The cracks that signify the existence of a door can also distract from the pure lines of the design, so these significant cues are also minimized or eliminated. The result can be a smooth expanse of gleaming material, with no sign of doors or drawers, let alone of how those doors and drawers might be operated. Electric switches are often hidden: many electric typewriters have the on/off switch hidden underneath; many computers and computer terminals have the on/off switch in the rear, difficult to find and awkward to use;5 and the switches that control kitchen garbage disposal units are often hidden away, sometimes nearly impossible to find.
Many systems are vastly improved by the act of making visible what was invisible before. Consider the VCR.
“UMPTEEN-DAY-UMPTEEN-EVENT PROGRAMMING. Because time-shifting is so popular, manufacturers and retailers play up a VCR’s ability to record automatically. The typical VCR can record four events (video jargon for programs) over a 4-day span....
“It’s one thing to know that a VCR can record eight events in 14 days. It’s quite another to make the machine behave. You have to go through a tedious series of steps to tell the VCR when to start recording, what channel to record, how long to run the tape, and so on.
“Some VCR’s are much easier to program than others.... Best of all, we think, is a feature called on-screen programming. Commands that appear on the TV screen help you enter the time, date, and channel of the program you want to tape. ”6
As the quotation from Consumer Reports indicates, the act of setting up these units to do the recording is horribly complex and difficult. The same article later warns that if you are not careful in your selection,
“you could wind up with a VCR that brings out fear and loathing whenever you try to change the channel resets or set it up to record a program when you are away.” It does not take much examination to discover the reason for the difficulties: there is no visual feedback. As a result, users (1) have trouble remembering their place in the lengthy sequence of required steps; (2) have trouble remembering what next needs to be done; and (3) cannot easily check the information just entered to see if it is what was intended, and then cannot easily change it, if they decide it is wrong.
The gulfs both in execution (the first two problems) and in evaluation (the last problem) are significant for these VCRs. Both can be bridged by the use of a display. Displays often cost money and take up room, which is why designers hesitate to use them, but in the case of a VCR, a display device is usually already available: the TV set. And, indeed, those VCRs that can be programmed through the use of an on-screen TV display are much easier to use. Visibility makes all the difference.
NOTHING SUCCEEDS LIKE A GOOD DISPLAY
Over and over again we find unwarranted complexity that could be avoided were the device to contain a good display. With the modern