Trust
If operators do not trust their
sensors and displays, expert advisory system, or automatic control system, they
will not use it or will avoid using it if possible. On the other hand, if
operators come to place too much trust in such systems they will let down their
guard, become complacent, and, when it fails, not be prepared. The question of
operator trust in the automation is an important current issue in humanmachine interface
design. It is desirable that operators trust their systems, but it is also
desirable that they maintain alertness, situation awareness, and readiness to
take over.
Alienation
There is a set of broader social
effects that the new human-machine interaction can have, which can be discussed under the rubric of alienation.
1. People worry that computers can
do some tasks much better than they themselves can, such as memory and
calculation. Surely, people should not try to compete in this arena.
2. Supervisory control tends to
make people remote from the ultimate operations they are supposed to be
overseeing — remote in space, desynchronized in time, and interacting with a
computer instead of the end product or service itself.
3. People lose the
perceptual-motor skills which in many cases gave them their identity. They
become "deskilled", and, if ever called upon to use their previous
well-honed skills, they could not.
4. Increasingly, people who use
computers in supervisory control or in other ways, whether intentionally or
not, are denied access to the knowledge to understand what is going on inside
the computer.
5. Partly as a result of factor 4,
the computer becomes mysterious, and the untutored user comes to attribute to
the computer more capability, wisdom, or blame than is appropriate.
6. Because computer-based systems
are growing more complex, and people are being “elevated” to roles of
supervising larger and larger aggregates of hardware and software, the stakes
naturally become higher. Where a human error before might have gone unnoticed
and been easily corrected, now such an error could precipitate a disaster.
7. The last factor in alienation
is similar to the first, but all-encompassing, namely, the fear that a “race”
of machines is becoming more powerful than the human race.
These seven factors, and the fears
they engender, whether justified or not, must be reckoned with.
Computers must be made to be not
only “human friendly” but also not alienating with respect to these broader
factors. Operators and users must become computer literate at whatever level of
sophistication they can deal with.
How Far to Go with Automation
There is no question but that the
trend toward supervisory control is changing the role of the human operator,
posing fewer requirements on continuous sensory-motor skill and more on
planning, monitoring, and supervising the computer. As computers take over more
and more of the sensory-motor skill functions, new questions are being raised
regarding how the interface should be designed to provide the best cooperation
between human and machine. Among these questions are: To what degree should the
system be automated? How much “help” from the computer is desirable? What are
the points of diminishing returns?
Table lists ten levels of
automation, from 0 to 100% computer control. Obviously, there are few tasks
which have achieved 100% computer control, but new technology pushes
relentlessly in that direction. It is instructive to consider the various
intermediate levels of Table 6.1.1 in terms not only of how capable and
reliable is the technology but what is desirable in terms of safety and
satisfaction of the human operators and the general public.
Scale of Degrees
of Automation
1. The computer offers no
assistance; the human must do it all.
2. The computer offers a complete
set of action alternatives, and
3. Narrows the selection down to a
few, or
4. Suggests one alternative, and
5. Executes that suggestion if the
human approves, or
6. Allows the human a restricted
time to veto before automatic execution, or
7. Executes automatically, then
necessarily informs the human, or
8. Informs the human only if
asked, or
9. Informs the human only if it,
the computer, decides to
10. The computer decides
everything and acts autonomously, ignoring the human.
The current controversy about how
much to automate large commercial transport aircraft is often couched in these
terms
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