 |
At least in part, the act of perception relates to physical elements - everything from your
eyesight to the condition of the audio system in the rented airplane you are flying. The
five senses of sight, sound, smell, touch, and taste are the conduits for 100 percent of
the external information going to your brain. The filters mentioned above are those
circumstances that block some or all of that information from making the journey from
outside your head to inside your head. Perception (i.e.,
the act of acquiring information) is also affected by limitations of the human brain:
-
Processing in the human brain is limited to about four bits of information per second.
-
Working memory capacity is limited to about seven (plus or minus two) chunks, or pieces,
of information at a time.
However, our experience, education, and intuition give us the ability
to ""fill in" gaps in what we really obtained through the five senses.
For example, you may not have heard exactly every single word of
the ground controller's taxi instructions, but your experience, training, intuition,
and expectation help you fill in the missing words. Internal influences, such as
motivation, attitude, emotion, distraction, and pre-disposition (e.g., expectation)
also play a role in how your brain compensates for missing information. The problem,
of course, is that you might fill in the gaps incorrectly, and that since
the "fill-in" activity is so smooth and automatic, you may not even be aware
that it has occurred.
Pilot Error
Going back to the previous example of the taxi instructions: suppose that you are in
a rented airplane with a scratchy radio. You have several passengers on board who are
chatting among themselves. You are tired, but the airport is your home base, and you
know the normal procedures like the back of your hand. You therefore know exactly what
that taxi clearance from your parking spot to the active runway is likely to be. The bad
radios and the noise from your passengers causes you to miss a few words of the ground
controller's instructions....but because your brain is expecting a certain sequence, it
automatically fills in the missing words. Today, however, the ground controller gave
you different instructions, which you "heard" as the normal taxi clearance.
The problem is clear, and it escalates at each step of the ADM process: because you
perceived incorrectly, you process (evaluate) the taxi clearance and judge it to
be "routine," even though it is not. The mistake becomes greater, and possibly
more dangerous (e.g., runway incursion), when you perform on the basis of the incorrect
information.
The example above begins with a perceptual error, in which you simply do
not see, hear, or notice a particular piece of information. Human beings are also
vulnerable to procedural errors, such as when you correctly perceive
and mentally process the controller's instruction to change to a new radio frequency,
but you enter it incorrectly in the radio itself. Forgetting to lower the landing gear
is another example of a procedural error.
Researchers who study human decision making processes have also identified a third kind of
error: the decisional error. An example of a decisional error is
continuing VFR flight into IMC when you and/or your aircraft are not equipped for this
kind of operation. As you might imagine, decisional errors are complicated, because they
arise from a large number of other factors. As we saw in the taxi clearance example,
errors in how you perceive and process information can lead to decisional errors, which
in turn affect your performance. Other factors that play a part in decisional error
include:
- Framing the alternatives. Any set of alternatives can be articulated,
or "framed," in positive or negative terms. Framing in positive terms can
support a higher risk decision; for example: "I know that the weather at my
destination is marginal, but I can get there so much faster in the airplane than I can in
the car." Framing in the negative, on the other hand, can help bring a much-
needed touch or reality into the ADM process. For example: "If I find that
I cannot land at my destination, I will be stuck at another airport, which would make me
late for this appointment."
- Judgmental Heuristics. This term simply means that human beings
sometimes jump to a conclusion too quickly, without considering all available (or all
relevant) input.
- Bias. There are several types of bias at play in human decision making
processes. One is confirmation bias, which is the human tendency to
look for information to confirm a decision already made. The taxi clearance example
above involves some degree of confirmation bias, since a pilot who expects a certain
clearance might simply "hear" what he or she expected to hear, rather than
what was actually said.
- Expertise, Training, Experience. Everyone sees the world in terms of
individual life experience and training. Two pilots faced with the same situation will
very likely make different decisions, based upon how they filter the information and upon
past experience and training. In the taxi clearance example, a pilot who is new to a
particular airport has no experience with local procedures, and thus has no preconceived
ideas about what the clearance "should" be. That pilot's lack of experience with
the airport can lead to a very different perception of the situation than that of the
pilot whose aircraft is based there.
|
