If your computer sometimes makes your blood boil, you're
perfectly normal. In fact, a Stanford University
researcher claims that computers stimulate a wide range of
emotional responses that mirror real-life human
interactions.
"People respond to computers according to the same rules
and principles that govern how they respond to other
people," says Clifford Nass, an associate professor of
communications at Stanford. Nass and colleague Byron
Reeves have conducted more than 40 scientific experiments
that measure the physiological and psychological responses
of computer users. They are publishing their findings in a
new book, The Media Equation: How People Treat Computers
(Cambridge University Press), that contains some
fascinating insights for software designers.
For example, Nass and Reeves tested how users respond to
educational software that speaks with male or female
voices. They discovered that people consider "male"
computers to be better teachers of technical subjects, but
prefer "female" computers for more personal subjects.
Should software developers adhere to these stereotypes or
rebel against them? Nass dodges that question: "We're
scientists, not politicians."
However, he does offer more concrete advice on other
subjects. Above all, Nass emphasizes that computers don't
have to be artificially intelligent or even particularly
sophisticated for people to react to them as if they were
real people. In one experiment, Nass and Reeves used a
simple text-based terminal to see how people responded to
commands worded in dominant or passive language. Result:
Users with dominant personalities disliked passive
computers, and users with passive personalities disliked
dominant computers.
"The minute you put words on the screen, you've got a
social interface," Nass says. "If it's got contingent
behavior, if it fills a social role, and if it uses
language, people will perceive it as a person."
Six Tips for Better Interfaces
After studying the physiological and psychological
responses of computer users, Stanford University's
Clifford Nass says savvy user-interface designers should
keep these key issues in mind:
1. Error messages should have a consistent tone and
style. Many programs are inconsistent because different
programmers wrote the error messages, often as an
afterthought. Whether the tone is dominant, passive,
friendly, or businesslike can vary according to the type
of application, but it must be consistent. "Although
different people like different personalities, nobody
likes a confused personality," Nass says.
2. Users should be able to customize their software, but
it's better to offer them a few preconfigured choices
instead of forcing them to set a zillion separate
options. "If I asked you to describe your ideal best
friend, you'd probably have trouble," explains Nass.
"But if I showed you 10 people and asked you to choose
the one you like best, you'd find it much easier."
3. Avoid the overuse of modal alerts (messages that
float atop all other windows and must be dealt with
immediately). "A modal alert is like yelling 'Fire!'"
4. Context-sensitive help is much better than large,
generic help files that give too much nonspecific
information. If someone asked you for a phone number,
would you recite the phone book?
5. Toolbars are frustrating because users must remember
what all the obscure little icons mean. "They violate
the principles of understandability and comprehension,"
says Nass. Toolbars are acceptable if the user creates
the shortcut button. The toolbar should remain hidden by
default until the user is ready for it.
6. Practice random kindness and senseless acts of
beauty. In one of their most interesting experiments,
Nass and colleague Byron Reeves discovered that users
exhibit a measurable physiological response to random
praise, even if the praise is undeserved, and even
though people deny that praise from a computer matters
to them.
Does this mean software developers should counterbalance
their error messages with occasional "praise messages"?
It sounds crazy, but Nass and Reeves actually designed a
spelling checker that not only flags spelling errors but
also randomly praises the user for spelling difficult
words correctly. The program generates positive
responses that can be measured on brain scanners.
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