Washington & Jefferson College | channon@washjeff.edu
Warsa w Collection of Business Americana -Telephone, Archives Center, National Museum of American History, Behring Center, Smithsonian Institution
An 1878 brochure (at left) from the New England Telephone company, “How to Make a Telephone Call,” explains, with illustrations, the use of its new instrument. One of the drawings “represents a person calling attention by pressing the knob at the end of Bell Box, and turning the crank, causing the Bell at the other station to ring. When the person at the other end hears the call, he will call back; then both will turn the switches to button marked T [ 1].” As the instructions continue, “The Telephone can then be used.” Of course, these early adopters began “using” the telephone the minute they pressed that knob and turned that crank. But the writer of this pamphlet understood that he was selling a revolutionary new experience, not the intricacies of a complicated machine. He needed to bracket off the preliminary manipulation of buttons and cranks as something different from this new and seemingly magical phenomenon of talking to another human over a great distance.
And yet those pesky controls required attention. This was a machine that demanded some expertise. As the pamphlet emphatically notes, “When you have finished talking, BE SURE AND TURN THE SWITCH TO BUTTON MARKED B.” Oh, and watch out if the sky clouds up:
“If a thunderstorm threatens, insert the plug that is supplied with the Bell, into the hole marked A.” This presumably breaks the circuit between the two telephones and prevents electricity from a lightning strike from traveling along the wires that connect them. But remember to remove the plug the next time you want to make a call!
It is easy to laugh at how difficult previous generations of technology were to use, especially once they have matured and become everyday consumer items. Many improvements arise from better materials, manufacturing processes, and engineering: The physical design of a machine has to account for how the human body is built, what kinds of controls best match the capabilities of the human hand, ear, foot, etc. These early telephones required two hands and a great deal of manual dexterity to press knobs, turn cranks, hold ear- (and sometimes mouth-) pieces. But as readers of interactions know, advancements in industrial design must be informed by principles of human cognition that make using such devices something that we don’t have to think about very much. Central to this process is an understanding of the role of mental and conceptual models in interaction design.
Donald Norman began this
discussion for the current generation of interaction designers with the simple axiom, “A good conceptual model allows us to predict the effects of our actions [ 2].” In Norman’s view, systems should present accurate images of how they work, whether through the controls in the interface, or through accompanying marketing material, instruction manuals, diagrams, support sites, etc. Problems occur when the conceptual model is faulty, when the system’s image of itself is inaccurate. This often results when marketers or technical writers attempt to simplify for consumers the intricate details of a design. When the system breaks down or doesn’t perform the way a user expects, the inaccurate system image reveals a fissure between the user’s understanding of how a system works and how it actually does work. In Norman’s classic example, he has trouble adjusting the temperature of his refrigerator compartments: The system image indicates that the freezer and cooler compartments can be controlled independently, when in fact there is only one cooler for the unit and controls that direct more or less cool air to one section or the other. He finds it impossible to alter the temperature in one compartment without affecting the other compartment as well, and this con-
[ 1] Ierley, Merritt. Wondrous Contrivances: Technology at the Threshold. Ne w York: Clarkson Potter, 2002, 112–118.
[ 2] Norman, Donald. Design of Everyday Things. Ne w York: Doubleday/Currency, 1990.
September + October 2008
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