Civil Engineering Reference
In-Depth Information
FIGURE 18.5
James Reason's error
model (1990).
RULE-BASED MISTAKES
These mistakes are different in nature. They don't require deep thinking, as with a
knowledge-based situation. In this case the operator uses a set of rules which can be
formulated as if-then conditions. If A, then do X; if B, then do Y; if C, then do Z. If
dialing to the U.S., use country code 1; for Sweden, use 46; for Singapore, use 65.
Sometimes I mix them up and I have no idea that I made a mistake.
Another example comes from driving in wintertime. If the road turns to the right, I
steer to the right. If the road turns to the right and there is ice on the road and I skid, then
I first steer to the left. This will compensate for the skid and the car will be appropriately
repositioned on the road. Then I steer to the right to take the curve.
Rule-based mistakes tend to be done with much confidence: “strong but wrong.” A
person can mention all the decision rules he uses, and he may say that it is inconceivable
that he could have made a mistake. In fact, he just simply forgot what he did. Rule-based
decisions are more or less automatic, so people don't attend to their own behavior—
hence it is easy to forget what one just did.
SLIPS
Slips are different from mistakes. In this case the person has the right intention, but the
task is carried out incorrectly. A common class of slips is called capture errors. These
may happen when
• The intended action is almost the same as the routine action
• The action sequence is relatively automatic
For example, as you sit at the breakfast table reading a newspaper you pour yourself a
glass of orange juice. Then you pick up the glass to drink, but it is not orange juice; it's
