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SCORE-653 for CsLEOS™
RTOS - A Strong Platform for Safety
Critical Software Development
The integration of DDC-I’s SCORE® (Safety Critical, Object-oriented, Real-time Embedded) suite of
programming and testing tools with the CsLEOS™ RTOS (Real Time
Operating System) from BAE SYSTEMS Controls combines a robust
development environment and an ARINC-653 compliant RTOS that are
both designed for use in the development of high-integrity embedded
systems. For the first time, the SCORE® multi-language
support provides the application developer the ability to utilize C,
embedded C++ & Ada for developing ARINC-653 applications to run
with the CsLEOS™ RTOS.
The SCORE® Integrated Development
Environment with CsLEOS™ RTOS support runs on Solaris and Windows
NT® platforms to generate and debug applications targeted for the
PowerPC family of processors. The SCORE® CsLEOS™ RTOS support
encompasses multiple language compilers, an Ada librarian, a target
linker, disassembly tools, testing tools, and a
Multi-Language Debugger (MLD), all unified through a Graphical User
Interface (GUI).
The CsLEOS™ RTOS
The CsLEOS™ Real-Time Operating System is the
first commercial, off-the-shelf RTOS, offered by a safety-critical
systems company that is already certified to the highest FAA DO-178B
safety level. Designed from the outset to implement ARINC-653
spatial and temporal brick-wall partitioning, the CsLEOS™ RTOS
ensures that safety-critical functions are protected from other
processes running on the same hardware.
The architecture also makes it possible to add,
revise, and test system functions without re-certifying the entire
application. With the cost of the certification process being so
high, this can significantly reduce the bottom line when developing
or enhancing airworthy software.
The RTOS's ARINC 653-compliant API (Applications
Programming Interface) is a true open system, offering users the
ability to develop application software to a standard set of
interfaces. This ensures ease of use and the most efficient use of
development resources.
The CsLEOS™ RTOS is available now; already
certified to DO-178B, Level A (D0-178B, developed by RTCA Inc., a
nonprofit company in Washington, D.C., is the international standard
for certifying software used in safety-critical airborne systems,)
eliminating the need for the application developer to certify the
operating system as well as their own application code in the final
product.
CsLEOS™ RTOS has pre-configured BSPs (Board
Support Packages) for a wide range of PowerPC® target
boards. The CsLEOS™ RTOS BSPs contain all the required code for
initializing and utilizing all the board specific hardware required
by the kernel.
SCORE-653 Support for the CsLEOS™ RTOS
The SCORE-653 development environment supports
compilation, linking, testing, and debugging of applications running
on top of the CsLEOS™ RTOS. Applications can be written in
embedded C++, C, Ada, or a mixture of the languages. Ada and C APIs
provide access to CsLEOS™ RTOS processes to support multi-process
applications, including processes, error handling, and inter-process
communications, all compliant with the ARINC-653 standard.
The SCORE-653 system has a clean,
board-independent interface to the CsLEOS™ RTOS, which is provided
through the SCORE-653 CsLEOS™ RTOS UCC (User Configurable Code).
This interface is the link between the SCORE® target
libraries, primarily the SCORE® Run-Time System, and
CsLEOS™ RTOS. The interface has been designed to ensure that
hardware and board specific details are positioned entirely within
the CsLEOS™ RTOS domain. This means that the SCORE®
target code is 100% board independent and that SCORE-653 CsLEOS™
RTOS applications can run on any hardware that has a CsLEOS™ RTOS
BSP (Board Support Package).
An Ada library is provided with interface
packages containing Ada bindings to the CsLEOS™ RTOS system calls.
This provides a seamless interface from Ada to CsLEOS™ RTOS while
maintaining the safety of Ada’s inherent type checking. An
Interface pragma has been included in the Ada compiler, which allows
the user to check at compile-time that no unsafe features have been
included in the application code. The combination of Ada’s
reliability, provided through strong typing and rigorous checks, and
the built-in safety features of the certified CsLEOS™ RTOS, offers
a strong platform for safety-critical software development.
The complexity of generating a set of CsLEOS™
RTOS executables is eased by automatic transfer of addresses between
the CsLEOS™ RTOS configuration files and the SCORE®
build process. Partition addresses from the CsLEOS™ RTOS
configuration database must correspond to those entered for the
SCORE® build process. Normally these hex addresses would
need to be transferred by hand, but the integration of SCORE®
and CsLEOS™ RTOS has automated that process, reducing the
possibility of transcription errors.
SCORE® also provides a PowerPC
simulator to allow source code debugging of algorithms on a PC.
Within the simulator the user also has full access to the PowerPC
register set and can examine the execution of programs at machine
code level. Debug statements may be added to help trace execution
and will display information on a dedicated window. The CsLEOS™
RTOS provides a special BSP to support the simulator.
On the real target hardware, symbolic debugging
of the source code is accomplished through a JTAG interface.
Applications will run in real time until a breakpoint is reached.
The SCORE® MLD (Multi Language Debugger) will seamlessly
debug Embedded C++ code, C code, Ada code, and machine code,
changing its operating mode automatically to match the language at
the point of visibility. Watch windows allow the monitoring of both
registers and expressions to ease the detection of changing data.
Based on personal preferences, the SCORE-653 CsLEOS™
RTOS user can choose either to work from the command line
using SCORE® commands, or from the SCORE®
GUI, which integrates all the SCORE-653 tools. Being able to compile
and link from the command line allows the user to automate the
compile and build processes, while the easy-to-use GUI executes
SCORE® commands with a single mouse-click.
The SCORE-653 MLD (Multi Language Debugger) can
be used either from the GUI or from the command line to perform the
usual Ada and C source code debugging of CsLEOS™ RTOS
applications. In addition, SCORE® has added expression
watch windows that allow the user to automatically evaluate an
expression at each tracepoint or breakpoint. Extensive machine code
debugging options allow disassembly of machine code instructions,
single stepping of machine code, and display and monitoring of
register contents. The MLD interfaces to the hardware under test
through a JTAG connecter. The MLD can be used to download programs
onto the hardware, or can provide full symbolic, source level
debugging of programs already downloaded into RAM.
The debug process may be automated through the
powerful command language, which may be embedded in startup and
initialization files, and session logging ability. This allows the
user to create automated test scripts which can be used to perform
white box testing. The ability to repeat the same tests easily is
invaluable during regression testing.
To support testing even more thoroughly, SCORE®
is integrated with the SCORECast toolset, an automated module test
system designed for embedded systems. This provides unit level
testing of C, Ada, and C++ code as it runs on the PowerPC simulator.
It will show source level coverage at the statement level, the
branch level, and MC/DC level, an essential tool for certifying to
DO-178B level A.
In summary, SCORE-653, a natural integration of
DDC-I’s Safety Critical Real Time multi-language development
environment and BAE SYSTEMS Platform Solutions CsLEOS™ ARINC-653
compliant Real-Time Operating System, is the solution of choice for
applications requiring DO-178B certification or any application
where safety is paramount.
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DDC-I Provides Current TADS-i960
Customers With
Cost-Effective Windows Migration Package
Phoenix, AZ — May 15, 2003 — To streamline the
transition from VAX or UNIX-hosted development systems, DDC-I
announces the availability of a new Windows® (NT/2000/XP) migration
package for existing TADS-i960 users. A fully customizable
limited-time package, it offers current customers a simple, affordable
migration path to the most popular PC-based network and enterprise
computing platform.
"Our flexible TADS for Windows migration
package allows customers to define which tools and support they
require, rather than sticking them with a rigid list of tiered
options," explains Harold "Bud" Blum, DDC-I Senior
Software Engineer and Product Champion for the TADS-i960 product line.
With DDC-I's expert guidance, customers dictate
package parameters, creating a least-cost migration path including
necessary license transfers and keys to replace all current TADS
licenses. To keep recurring costs level, software support from any
current license agreement carries over, and the customer has complete
freedom to select the quantity of seats to rehost and whether to
upgrade their software versions during the migration.
The package also includes two days of on-site
consulting at no additional charge to assist with rescripting, memory
and segment set up, tool adaption, related Ethernet work and UCC
upgrading. A final project report with detailed recommendations is
included.
"Our customers need their safety-critical
software development tools to keep pace with their development
environment, and upgrading our TADS products for the Windows platform
allows them to intelligently utilize their computing assets with
minimal disruption to the development environment they depend
on," Blum concludes.
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On the Front Lines
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Harold
(Bud)
Blum
Senior Software Engineer
TADS Product Champion
DJCS (JOVIAL) Product Champion
DDC-I, Inc.
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Introducing Harold (Bud)
Blum, Senior Software Engineer and Product Champion for both the TADS
Ada Development Systems (TADS) and the DDC-I JOVIAL Compiler Systems
(DJCS). As Product Champ, Bud has the responsibility for
"front-liner" support issues as well as ongoing development
and maintenance. Understanding each customer's specific needs and
expectations is the key to Bud's approach of establishing individual
partner relationships. Bud also takes an active role in support of the
DDC-I Sales and Marketing Departments with frequent technical
consultation and project proposals.
Bud grew up in the rural
Amish country of Northeast Ohio. His passion for music, as well as for
science and mathematics, led him to bachelor's and master's degrees in
Music Theory at Kent State University (yes, he was a student there in
May 1970), and onward to doctoral study in Music Theory at the
University of Michigan. Courses in computer science and formal
language theory, adjunct to dissertation research in musical analysis,
expanded to become an MS in Computer and Communication Sciences from
Michigan in 1983.
Bud has worked for Burroughs
Corp. in Michigan and System Development Corp. (SDC) in California,
which both became Unisys Corp. His experience there includes embedded
systems development for high-speed document processors (check sorters)
for the Federal Reserve Banking System, and an optical digital image
storage system for the National Archives in Washington DC. Bud also
worked on a military air traffic controller training system used by
both US and allied forces, and the integrated retail terminal system
used by the US Postal Service. Bud later joined Computer Task Group, a
worldwide consulting firm, in their Cleveland Ohio office, where he
worked with clients such as Loral Corp. and Roadway Express. Bud
brought his extensive experience in the development of government and
military computer systems to DDC-I in 2000.
Bud lives with his wife Cindy
in Phoenix Arizona, where he also has extended family. He enjoys
science fiction, renaissance choral polyphony, casino blackjack,
crossword puzzles (in ink), and not having to shovel snow in the
winter anymore. Cindy and Bud are active supporters of various animal
shelters and humane societies, and they share their home with 11 cats
and a Siberian Husky named Nikolai. Serious incompatibilities
notwithstanding, Bud (Michigan -- Go Blue!) and Cindy (Ohio State --
Go Bucks!) recently celebrated their 25th wedding anniversary.
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Influence
Strategies - Part I
By Linda Rising
Did you know that the world's foremost expert on
influence is a professor at Arizona State? As an Arizona resident, I was
surprised to learn about the years of research that have identified a
collection of basic influence strategies. Most of us in technical areas
believe that all you need is the right kind of data and a logical
argument to convince anyone that you have a good idea. Typically,
however, this only works when the listener is already convinced that the
idea is a good one. If the listener is not convinced, some or all of
these influence strategies may help you.
To conduct the research, Arizona State University professor, Robert
Cialdini left the university environment and went out into the world to
study professions where the practitioners are masters at getting others
to say yes. Cialdini began with training. He learned how to sell
automobiles from a lot, insurance from an office, portrait photography
over the phone. He visited advertising agencies and public relations
firms. He interviewed fundraisers at charity organizations and
recruiters: armed service recruiters, even cult recruiters.
Across it all, he looked for commonalities—patterns! He saw hundreds,
maybe thousands of individual practices, but he was able to classify
most into six basic principles of influence. As a side note, the six
principles do not include material self-interest: that people want to
get the most and pay the least for their choices—a motivational given
or axiom.
Since these principles are so powerful, Cialdini is very concerned about
their ethical use. He points out a practical reason for using these
principles ethically—to produce the long-term relationships needed to
grow a business. These relationships are built on the trust that results
when people have been steered to the right choices—not fooled into
believing something that might not hold for them.
Automatic stereotyped behavior is part of human action because it is
efficient and necessary for survival in a complicated environment. We
can’t analyze every situation we encounter every day. Instead, we use
stereotypes to classify things and then respond without thinking. Of
course, not even the best stereotypes work every time. When we want to
and are able to we will analyze information.
As you read these principles, realize that we remain
ignorant about persuasion because we refuse to admit that we are
affected by politicians, salespeople, advertisers, and other influence
professionals. The reality is—none of us is immune to influence. In
many of the studies reported here, the subjects were asked before or
after the experiment whether they believed they would be influenced and
most said they would not. In the experiment, of course, they were
influenced, just as we all would be!
Here are the six principles:
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The principle of liking. People like those who
are like them.
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The principle of reciprocity. People repay in
kind.
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The principle of social proof. People follow the
lead of similar others.
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The principle of consistency. People align with
their clear commitments.
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The principle of authority. People defer to
experts.
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The principle of scarcity. People want more of
what they can have less of.
We’ll examine the first three in this article and
tackle the other three next month. For each principle, we’ll consider
current research, how you can apply it in your business, and, also, how
you can defend yourself against it.
The principle of liking
One of the oldest axioms in the world of business is
that people buy from people they like. The question is, how do you
get to be likable? Considerable research into this question has
identified the following factors in liking:
Physical attractiveness. Research has shown that
we automatically assign to good-looking individuals such attributes as
talent, kindness, honesty, and intelligence, and we do this without
being aware that attractiveness plays a role. A study of Canadian
federal elections found that attractive candidates received more than
two and a half times as many votes as unattractive ones. We also see
this in hiring. In one study attractiveness accounted for more favorable
hiring decisions than did job qualifications—even though the
interviewers claimed that appearance did not influence their choices.
Attractive workers get paid an average of 12-14% more than their
unattractive co-workers. Attractive people are more likely to get help
when they need it and they are more persuasive in changing the opinions
of an audience.
Attractive people receive more favorable treatment in
our judicial process. Handsome men receive significantly lighter
sentences. In fact, attractive defendants are twice as likely to avoid
jail. Higher awards are given to more attractive victims. The bias is
exhibited by both male and female jurors. In one study of unattractive
criminals, one-third were given plastic surgery, one-third
rehabilitation services, while one-third were given nothing. One year
after the study, those given the plastic surgery were significantly less
likely to have returned to jail, while there was no difference in those
receiving rehabilitation services or not. This doesn’t mean that the
attractive criminals are less likely to commit a crime, only that they
are less likely to be sent to jail for it.
Similarities. We like people who are like us and
we believe this holds for others. A former producer of the Oprah Winfrey
show said that when the show started, Oprah weighed a lot more than she
does now. Many of the women in the audience also had weight problems.
When Oprah began to lose weight, the producers were worried that they
would lose that audience—and they did. In focus groups they said,
"OK, so now Oprah doesn't weigh as much so I guess you're not as
much like Oprah, so I guess you don't like her as much and that's why
you're not watching." But the women said, "No. Now that she's
thin we don't think she'd like us anymore. That's why we're not
watching."
We are more likely to help people who dress like us.
Experimenters asked college students for money to make a phone call.
When they were dressed like hippies the request was granted less than
half the time. When they were dressed like the students, the money was
given in more than 2/3 of the cases.
Researchers who examined sales records of insurance
companies found that customers were more likely to buy insurance from a
salesperson like them in age, religion, politics, and cigarette-smoking
habits.
When asked to rank order a waiting list of patients
suffering from kidney disorder for the next available treatment, people
chose those whose political party preference matched their own.
Compliments. McLean Stevenson said his wife
tricked him into marrying her. "She said she liked me." If
someone likes us, this can produce return liking and compliance. The
world’s most successful car salesman sends a card to his customers
each month saying, "Happy Valentine’s Day (or something
appropriate) and I like you."
One research study involved three groups of men and
someone who was soliciting a favor. One group received only praise from
the solicitor. One group received only negative comments. One group
received a mixture. The group who received only praise liked the
solicitor best, even when the men fully realized that the flatter stood
to gain from their liking. Pure praise doesn’t even have to be
accurate to work. Positive comments produce the same result even if they’re
not true.
Contact and Cooperation. Voters often choose a
candidate because the name seems familiar. In Ohio, a weak candidate
claimed a significant victory, when, shortly before the election, he
changed his name to Brown—a family name with a long political history
in Ohio.
Often we don’t realize that our attitude toward
something has been influenced by the number of times we have been
exposed to it in the past. In one study, faces were flashed on the
screen so fast that subjects couldn’t really see them but the more
frequently a face was flashed on the screen the more subjects came to
like that person when they met later. The subjects were also more
persuaded by opinions of those whose faces had appeared on the screen
more frequently.
Car salesmen use this principle. They claim to be on
our side and fight for a good deal with the boss. In the good cop/bad
cop scenario, in order to get a confession from a suspect, the bad cop
throws things and calls the suspect names and threatens him. Then good
cop sends the bad cop out and tries to befriend the suspect to encourage
him to talk.
Conditioning and Association. An innocent
association with either bad things or good things will influence how
people feel about us. We dislike the person who brings us bad news, even
when that person did not cause the bad situation. We blame the
weatherman for bad weather. Our parents told us about "guilt by
association" and warned us not to befriend the neighbor kids who
were a bad lot, since people would assume that we have the same
personality traits as our friends.
Good-looking models are in automobile ads because
advertisers know we transfer the beauty and desirability of the model to
the cars. In one study men who saw a new car ad with a seductive female
model rated the car as faster, more appealing, more expensive-looking,
and better designed than those who saw the same ad without the model.
When asked later, the men refused to believe that the presence of the
model had influenced their judgment.
Advertisers hire professional athletes to endorse
their products. The connection doesn’t even have to be logical.
Popular entertainers endorse political candidates and sway voters. A
comment by one voter: "They’ve got big stars speaking for it, and
big stars speaking against it. You don’t know how to vote!"
Researchers found that subjects became fonder of
people and things they experienced while they were eating. Subjects were
presented with political statements they had previously rated. At the
end of the experiment, some statements had gained in approval—those
that had been shown while food was eaten. The changes seemed to have
occurred unconsciously; since the subjects could not remember which
statements they had seen while food was served. This, of course, is an
important component of a well-known pattern, Do Food!
The principle also works for unpleasant experiences.
Political statements shown while putrid odors were piped into the room
caused approval rating to decline.
The relationship between a sport and its serious fans
is intense and personal. Fans are personally diminished by defeat and
personally enhanced by victory. Isaac Asimov has noted, "All things
being equal, you root for your own sex, your own culture, your own
locality. Whomever you root for represents you, and when he or she wins,
you win." Fans are grateful to those responsible for victories and
angry toward those responsible for failures. There are many ways we go
about this, but one of the simplest is the pronouns we use. After a
victory, "We’re number one!" After a defeat, "They
lost. Arizona State got beat." "Arizona State lost it. They
threw away our chance for a national championship."
Putting the liking principle to work
To influence people find a way to like them. The
ethical way to do that is to find a genuine connection. Find something
commendable about the person and remark on it. Give genuine praise and
not only will that person come to like you, but you will like the other
person because you have found something in common. We are just as
susceptible to this principle as the person we're talking to. The result
is—you've got the best possible context for ongoing continuous
business—two people who like one another.
We also like those we cooperate with in working
toward common goals. A recent study showed that in a conflict, even when
people had a genuine common interest, most of the time, they didn’t
recognize that commonality; they only saw the difference of opinion.
Find the commonality. Bring that to the surface. When you are working in
a context of a shared set of goals, it changes everything.
Beware: Because it is so easy to create the impression of similarity or
liking, be careful around people who claim to be "just like
you." Even mirroring body language, mood, and verbal style can lead
to positive results. Often when people flatter us or claim they like us,
they want something from us.
The principle of reciprocity
An experimenter sent Christmas cards to perfect
strangers and was surprised at how many responded by sending him a card.
This illustrates the most powerful of the influence principles—the
reciprocity rule: we try to repay, in kind, what another person has
given us.
This principle is evident in all cultures. Even
countries follow it. In 1985 Ethiopia was enduring the greatest
suffering and privation in the world but local officials decided to send
$5000 to Mexico to help victims of the earthquakes in Mexico City. Why
was the money sent? Because in 1935, Mexico had sent aid to Ethiopia
when it was invaded by Italy.
How did the Hare Krishnas increase contributions?
They began to offer gifts—especially effective were flowers. "It
is our gift to you." Busy people forced to accept the gift and
would then feel compelled to give a donation. Almost all donors tossed
the flower away. The Krishnas would rescue the flower and press it on
the next passerby, repeating the influence cycle.
One study showed that sending money with a
questionnaire greatly increased replies compared to offering the same
reward after-the-fact. One study showed that a $5 gift up front was
twice as effective at getting returns as a $50 offer for completing the
survey.
In general, after accepting a gift, customers are
willing to purchase products and services they would otherwise have
declined. Providing free samples uses the reciprocity principle, while
appearing to have only the intention to inform.
In politics, this is called "logrolling."
Lyndon Johnson was especially successful in getting many programs
through Congress during his early administration. Even those thought to
be strongly opposed to the proposals voted for them. The reason was the
large number of favors he had been able to provide to others during his
many years in the House and Senate. This may account for the problems
Jimmy Carter had in getting programs though Congress during his early
administration, despite heavy Democratic majorities in both House and
Senate. Carter came to the presidency from outside Washington. He
campaigned saying he was indebted to no one. The problem was—no one
was indebted to him.
The same effect is produced when corporations or
individuals provide gifts and favors. When one businessman at
congressional hearings on campaign finance reform was asked if he felt
he received a good return on his $300,000 contribution, he smiled and
replied, "I think next time, I’ll give $600,000."
Usually givers and takers dismiss the idea that
campaign contributions, free trips, and Super Bowl tickets bias the
opinions of government officials, but research shows the contrary. Even
medical professionals are affected. 100% of the scientists who found and
published results supportive of a certain drug had received free trips,
research funding, or employment from the pharmaceutical company while
only 37% of those critical of the drugs had received support.
Amway distributors leave a collection of Amway
products at a customer’s home to try "for 24, 48, or 72 hours, at
no cost or obligation." At the end of the trial period, the Amway
representative returns and picks up orders for products. Many customers
yield to a sense of obligation to order the products they have tried.
The American Disabled Veterans reports that its
simple mail appeal for donations produces an 18% response rate but when
the mailing includes an unsolicited gift, the success rate nearly
doubles.
The social pressure surrounding gift giving involves
the obligation to give, to receive, and to repay. An obligation to
receive reduces our ability to choose those to whom we wish to be
indebted and puts power in the hands of others. The effect is observed
with the Krishnas. The passerby is surprised by the gift of the flower,
does not want the flower and tries to give it back. The Krishna replies
that it is a gift—but that a donation would be appreciated. Despite
the resistance, a donation usually follows.
Surprise is effective in its own right. People who are
surprised by a request will often comply because they are momentarily
unsure what to do and, consequently, are influenced easily. People on a
New York subway were twice as likely to give up their seats to someone
who surprised them with the request than to one who forewarned them by
mentioning to a fellow passenger that he was thinking of asking for
someone’s seat.
A cross-cultural study (Americans, Swedes, Japanese)
has shown that those who break the reciprocity rule in the reverse
direction—by giving without allowing the recipient to repay—are also
disliked.
The sense of obligation persuades people to decline
gifts and benefits. Women feel uncomfortable when a man has given them
an expensive present or paid for a costly evening out. Even something as
small as a drink can produce a feeling of debt. One woman said, "I
no longer let a guy I meet in a club buy me a drink because I don’t
want either of us to feel that I am obligated sexually." Research
suggests that if a woman allows a man to buy her drinks, she is
immediately judged by both men and women as more sexually available to
him.
The reciprocity principle doesn’t apply to
long-term relationships—families or established friendships. What is
exchanged in these situations is the willingness to provide what the
other needs, when it is needed. It is not necessary to calculate who has
given more or less but only whether both parties are living up to the
general rule, although persistent inequities can cause problems.
Another form of the reciprocity rule says that a
person who acts in a certain way toward us is entitled to a similar
return action. If the other person makes a concession, we feel obligated
to make a similar concession. Many times participants in a negotiation
begin with demands that are unacceptable to the other parties. This
encourages making an initial sacrifice because it puts the other person
in the position of having to reciprocate. Making the initial concession
is part of a compliance technique called
"rejection-then-retreat," which involves making a large
request that will likely be refused, then making the smaller request you
really wanted. The other party will see the second request as a
concession and feel inclined to make a concession—which is compliance
with your second request.
Labor negotiators often use the tactic of making
extreme demands that they do not expect to win but from which they can
retreat and draw concessions from the opposing side. You’d think that
the larger the initial request, the more room for concession. This is
only true up to a point. Research shows that if the first set of demands
seems unreasonable, the proposer is seen as not bargaining in good
faith. The successful negotiator offers an initial proposal that is just
exaggerated enough to allow small reciprocal concessions and counter
offers that will give a desirable final offer.
One experiment determined whether the
rejection-then-retreat sequence caused people to feel so manipulated
that they would refuse further requests. College students were asked to
give a pint of blood in the annual campus blood drive. Targets in one
group were asked to give a pint of blood every 6 weeks for 3 years (the
initial extreme demand). When they refused they and the members of the
other target group were asked to give a single pint of blood (more
reasonable demand). Those who showed up to give blood were asked if they
would be willing to be called to donate in the future. Nearly all the
students who gave a pint of blood as a result of the
rejection-then-retreat technique agreed to donate again while fewer than
half of the other students did so. Thus, rejection-then-retreat not only
leads people to agree to a request but also to actually carry out the
request and then to volunteer to perform further requests. There are two
positive side effects of the concession: greater responsibility for and
satisfaction with the arrangement.
Putting the reciprocity principle to work
The business world is becoming a global enterprise
and reciprocity works everywhere. Every culture instructs its members
from childhood that they are obligated to return the behavior that was
given to them. In any situation, you don't say, "Who can help
me?" You want to say, "Whom can I help?" If we give
something first that provides benefit, then the receiver is likely to
help our business in return. It’s best if you don’t give tokens like
t-shirts or calendars but information that will help them do their job
better. Something like a report—not just a sales letter in disguise—but
something that is useful and valuable to the person who gets it. It
sends two messages. One: I'm thinking about you. Two: I care about
enhancing your business.
Even if that information turns out to be something
the person already knows, that's not important. What's important is that
you tried to help them and now, to live up to the rule of reciprocity,
they are likely to try to help you.
Beware: Accept offers from others but only for what
they are, not for what they are represented to be. If a person offers a
favor, we should recognize that we have obligated ourselves to a return
favor sometime in the future. If the initial favor turns out to be a
trick then we can be aware that the action is a compliance device and we
need no longer feel bound by the reciprocity rule.
The principle of social proof
We often decide what to do by looking at what people around us—just
like us—are doing. For example, even though people hate canned
laughter, it is popular with TV executives because research shows that
canned laughter causes an audience to laugh longer, more often, and to
rate the material as funnier. Evidence suggests that canned laughter is
most effective for poor jokes.
We determine what is correct by seeing what other
people think is correct. When we are unsure of ourselves, when the
situation is unclear or ambiguous, we are most likely to look to and
accept the actions of others as correct. This especially applies to
correct behavior—what to do with the empty box in the movie theater,
how fast to drive on a stretch of road, how to eat the chicken at a
dinner party. This principle works well. Usually we make fewer mistakes
by acting in accord with social evidence. Usually when a lot of people
are doing something, it is the right thing to do.
Bar tenders put dollars in the tip jar. Ushers add
money to the collection plate. Traveling evangelists seed their
audiences with ringers who are rehearsed to come forward to give witness
and donations. Nightclub owners create long waiting lines when there is
plenty of room inside. Advertisers tell us that a product is the
"fastest-growing" or "largest-selling." They don’t
have to convince us directly that the product is good; they only have to
say that others think so, which seems proof enough.
In one study, subjects who received a series of
electric shocks felt less pain (as indicated by self-reports,
psychophysical measures of sensory sensitivity, and such physiological
responses as heart rate and skin conductivity) when they were in the
presence of another subject who was tolerating (fake) shocks as if they
were not painful.
In one study, nursery-school-age children terrified
of dogs, watched a little boy playing happily with a dog for 20
minutes/day. This produced such marked changes in the fearful children
that after only 4 days, 2/3 were willing to climb into a pen with a dog
and stay to pet the animal. A month later, the improvement had not
diminished; in fact, the children were more willing to play with dogs. A
second study showed that simply watching film clips had the same effect.
The most effective showed a variety of other children playing with dogs.
Apparently, social proof works best when provided by the actions of many
other people. Try standing on a busy street corner, looking up. Alone,
you will not attract much attention but if three or four friends join
you, 80% of the passers-by will look up.
This causes a lot of anxiety for those concerned
about violence shown on television and in movies. Research has shown
that children act more aggressively toward one another after seeing
aggression on television.
We should be aware that other people are examining
social evidence, too. When everyone is looking to see what everyone else
is doing, this can lead to the failure of entire groups of bystanders to
aid victims who need help. A bystander to an emergency will be unlikely
to help when there are a number of other bystanders present. With
several potential helpers around, the personal responsibility of each
individual is reduced.
Experiments were performed where emergency events
were staged and observed either by a single person or a group. 85% of
the single persons came to the aid of the victim but in only 31% of the
cases was the victim helped when a group was present.
Putting the principle of social proof to work
Provide people with evidence that others like them
have made the choice that you're recommending. That means testimonials,
a list of people to call who've used your product or service. Those
satisfied customers can be more powerful sources of information and
persuasion than you can be in many situations because they're just like
the individual who is trying to decide.
Beware: In many cases the principle of social proof
is not valid. When the laugh track is bad or the advertising stunt using
an average person is clearly an actor. What does Angela Lansbury know
about pain relievers? A few years ago in Singapore, a bus strike had
created an unusually large crowd in front of a bank. Passersby assumed
that it was a crowd of customers ready to withdraw their funds from a
failing bank, so they did the same. Soon after opening its doors, the
bank was forced to close to prevent a complete crash. We seem to assume
that if a lot of people are doing the same thing, they must know
something we don’t. Especially when we are uncertain, we are willing
to place an enormous amount of trust in the collective knowledge of the
crowd. Quite frequently the crowd is mistaken because its members are
not acting on any superior information but are reacting to the principle
of social proof creating a situation of pluralistic ignorance.
Summary
Despite the danger of making stupid mistakes, the
pace of modern life demands that we use shortcuts. We can’t afford the
luxury of extended deliberations for each and every decision we make. We
are most likely to use shortcuts when we don’t have the inclination,
time, energy, or cognitive resources to completely analyze the
situation. When we are rushed, stressed, uncertain, indifferent,
distracted, or fatigued, we tend to focus on less of the information
available to us.
Most of the time these shortcuts work well for us. It’s
the reason why they have lasted. Many of them are hard-wired into our
genetic make-up. The structure of our society depends on our using
these. We need to be aware that they exist and use them to our benefit.
If you’ve used these principles successfully, I’d
like to hear your story! Send an e-mail to Linda Rising,
risingl@acm.org.
For more information on influence see:
Conversations with Industry Innovators, Dr. Robert Cialdini Interview,
September 1999,
http://www.lotus.com/solutions/manager.nsf/all/7EBBCB0D88D09AC785256801005A7064
Robert B. Cialdini, Influence: Science and Practice, 4th
ed., Allyn and Bacon, 2001.
Harry Mills, Artful Persuasion, Amacom, 2000.
About the Author
http://www.lindarising.org
risingl@acm.org
Linda Rising has a Ph.D. from Arizona State
University in the area of object-based design metrics. Her background
includes university teaching as well as work in industry in
telecommunications, avionics, and strategic weapons systems. She is the
author of numerous articles and has published three books: Design
Patterns in Communications, The Pattern Almanac 2000, and A Patterns
Handbook. She is currently writing a book with Mary Lynn Manns:
Introducing Patterns (or any Innovation) into Organizations, to appear
in 2003.
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