Design of Everyday Things [108]
Each newhour would last exactly 2.4 times an old hour: 144 old minutes. So the old one-hour period of the schoolroom or television program would be replaced with a half-newhour period-only 20 percent longer than the old. Each newminute would be quite similar to the current minute: 0.7 of an old minute, to be exact (each newminute would be about 42 old seconds). And each newsecond would be slightly shorter than an old second. The differences in durations could be gotten used to; they aren’t that large. And computations would be so much easier. I can hear the everyday conversations now:
“I’ll meet you at noon-5 newhours. Don’t be late, it’s only a half hour from now, 50 newminutes, OK?”
“What time is it? 7.85—15 minutes to the evening news.” What do I think of it? I wouldn’t go near it.
Deliberately Making Things Difficult
“How can good design (design that is usable and understandable) be balanced with the need for ‘secrecy’ or privacy, or protection? That is, some applications of design involve areas which are sensitive and necessitate strict control over who uses and understands them. Perhaps we don’t want any user-in-the-street to understand enough of a system to compromise its security. Couldn’t it be argued that some things shouldn’t be designed well? Can’t things be left cryptic, so that only those who have clearance, extended education, or whatever, can make use of the system? Sure, we have passwords, keys, and other types of security checks, but this can become wearisome for the privileged user. It appears that if good design is not ignored in some contexts, the purpose for the existence of the system will be nullified.“5
7.4 A School Door, Deliberately Made Difficult to Use. The school is for handicapped children; the school officials did not want children to be able to go in and out of the school without adult supervision. The principles of usability espoused in POET can be followed in reverse to make difficult those tasks that ought to be difficult.
Consider figure 7.4, a door on a school in Stapleford, England: the latches are up at the very top of the door, where they are both hard to find and hard to reach. This is good design, deliberately and carefully done. The door is to a school for handicapped children, and the school didn’t want the children to be able to get out to the street without an adult. Violating the rules of ease of use is just what is needed.
Most things are intended to be easy to use, but aren’t. But some things are deliberately difficult to use—and ought to be. The number of things that should be difficult to use is surprisingly large: • Any door designed to keep people in or out.
• Security systems, designed so that only authorized people will be able to use them.
• Dangerous equipment, which should be restricted.
• Dangerous operations, such as life-threatening actions. These can be designed so that one person alone can’t complete the action. I worked for a summer setting off dynamite underwater (to study underwater sound transmission); the circuits were set up to require two people to work them. Two buttons had to be depressed at the same time in order to set off the charge: one button outside, one inside the electronic recording trailer. Similar precautions are taken at military installations.
• Secret doors, cabinets, safes: you don’t want the average person even to know that they are there, let alone to be able to work them. These may require two different keys or combinations, meant to be carried or known by two people.
• Cases deliberately intended to disrupt the normal routine action (in chapter 5 I call these forcing functions). Examples include the acknowledgment required before permanently deleting a file from a computer storage system, safeties on pistols and guns, pins in fire extinguishers.
• Controls deliberately made big and spread far apart so that children will have difficulty operating