Human Error Dr. Earl E. Hansen, CIE

mattednearAI and Robotics

Dec 1, 2013 (3 years and 8 months ago)

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Human Error

D
r
. Earl E. Hansen, CIE


Human Error
-
Difficult to Discuss/Analyze



Relatively new field



Still trying to:



define its boundaries



define its terminology



define its taxonomy


Errors Happen



Seems trivial on the surface



No matter how good a system or
design is, people will make mistakes



some subscribe to the concept of “Normal Errors”
-
errors that are inevitable in
complex systems


Systems Can Encourage Errors



Errors are often attributed to the action of an individual
-
there are often a set of
external
forces & preceding events that lead up to the error.



These forces & events are difficult to anticipate.



Reaction is to punish individual and not to examine the system


Studying Human Error



Reinforces existing guidelines for good design.



Is the analysis o
f human performance.



Expects humans to make errors



Focus on error tolerance



Focus on error recovery



Focus on error prevention



New technologies will succeed or fail based on our ability to minimize the
incompatibilities between



the characteristics of peopl
e and



the characteristics of the things we create


Cognitive Science (Engineering)


A mix of different disciplines (psychology, philosophy, neuroscience, & artificial
intelligence


Ergonomics/Human Factors

Reviews specifics of human performance & how it

can be improved.



Ergonomics
-

Physical and Physiological.



Human Factors
-

Cybernetics/Mental


What Is Human Error?



“Human error: an inappropriate action, or intention to act, given a goal and the
context in which one is trying to reach that goal.” Ramon
, 1995

A Theory of Cognition

Accidents typically occur due to mental error.



James Reason
-

There are three basic kinds of mechanisms of thought
--



Skill
-
Based



Rules
-
Based



Knowledge
-
Based


Skill
-
Based

The ability to carry out a task; skill
-
based

cognitive pr
ocessing and performance refers

to
actions that are automatic and easy to due

to an acquired skill. Example: getting out bed.

Putting on a T
-
shirt, or opening a door
-

all of

which are unconscious actions one doe not

need to explicitly “think about” to

acc
omplish. Automatic which arm in what

hole.


Rule
-
Based

Matching the context & problem currently

facing the actor. These rules are typically of

the “if X then Y” form, can be based on past

experience, explicit instructions, etc.

Example
-
in leaving a room,
one normally

pushes the door to exit (automatic skill). If the

door does not open one start down a list of

reasons. Locked, pull, etc.


Knowledge
-
Based

If rule
-
based processing does not solve the problem,

we fall back on knowledge
-
based
processing (tend to

prefer rule
-
based solutions since they require less

cognitive effort on
our part). Occurs when faced

with novel or unfamiliar situations, or where low

level rules
are not appropriate (e.g. making strategic

decisions, diagnosis, etc.) Involves processing
o
f

symbolic information (suits in card deck) reduces

cognitive effort. Cognitive
mechanisms are Slips &

mistakes.


Slips: Errors of Action

Slip
-
Action not in accord with ones intentions: a good plan but poor execution. i.e.
fumble on a good play. They are p
art automatic, unconscious actions, slips are
unintended acts due to a break in the routine.


Slip Error Mechanisms



Capture slips
-
doing something automatically one did not intend to do. Fell into a
pattern one performs frequently.



Description slips
-
failed
to tell self correctly what one wants to do. Occurs when
intended action is similar to other actions done often.



Associative activation slips
-
occur when the brain makes a faulty connection or
mental association between tow ideas, often when one is an exter
nal stimulus that
typically provokes a certain action. e.g. answering phone when hearing the
doorbell.



Loss of Activation slips
-
occur when one loses track of what they are doing or
trying to do (the activation of the process). Essentially a temporary memor
y loss,
often due to interruption, asked a question, handed something. e.g. “now why did
I get up to come into this room in the first place?”


Mistakes:

Errors of Intention



Mistake
-

Stem from cognitive breakdowns; often influenced by external system
factor
s. A planning failure, when actions go as planned
--
but the plan was bad.
These are errors of judgement, influence, etc., that result in an incorrect intention,
incorrect choice of criterion, or incorrect value judgement. Mistakes are the real
challenges i
n the analysis of human error. Slips can be prevented through checks
built into tools/equipment.


Rule
-
Based Errors



Occur when:




the wrong rule chosen due to misperception of the situation



misapplication of rule


Knowledge
-
Based Errors



The most complex of

errors



Occurs from a lack of or misapplication of knowledge