Human error – Lecture 1 12/11
Error = the failure of planned actions to achieve their desired goals
without some unforeseen or chance intervention (Reason, 1990).
Error types:
1. Errors of Automation = stuff that you do, that you somewhat trained
in, that you do not pay much of attention to.
a. Slips: attention failure, action related
b. Lapses: memory failure, forget
2. Errors of conscious control = mistakes; we have a plan, can be good
or bad, and doesn’t work out to reach our goal.
a. Mistakes: intention failure
b. Violations? Is it an error when you know you have an violation?
Blaming is something we don’t do.
Rasmussen – human performance
Knowledge level: bounded rationality & “thinking” (problem solving)
Rule level: pattern matching & recognition, if… then…
Skill level: highly automated, very little/no effort
Behaviour moves between these levels. Something that you learn can
become skill level after you do it much. Skill level is very energy efficient,
if we would have to think about everything it would be very difficult.
Skill level: e.g. playing guitar, dancing. A lot of things we do in daily life we
could not do without skill level. Makes us respond quickly.
Rule level: e.g. we think a larger country means more inhabitants, but not
always true.
Knowledge level: problem solving and learning (also with animals)
Generic error-modelling system (GEMS)
Skill slips and lapses
Rule rule based mistakes
Knowledge knowledge-based mistakes
,Skill level errors: inattention/omission
Double-capture slips: distracter captures executive control; stronger
automation takes over.
Omissions following interruptions: attention checks fail after an
external event. Attention was distracted so you forgot to do
something.
Delay reduces control: detached intentions, environmental capture,
multiple sidesteps (walking upstairs and forgetting what you’re
doing)
Perceptual confusions: a pattern matching problem. Can have
serious consequences (e.g. gun and taser with police)
Interference errors: control issue, “blends”, “spoonerisms”. (e.g.
answering the phone at home the same way as you do at work as a
secretary). Freudian slip is where you say one thing but mean your
mother.
Skill level errors: over attention
Omissions
Repetitions
Reversals
o Sometimes it’s best not to think about doing something.
o When you don’t want to do something but still do it.
Rule level errors: misapplication of good rules
First exceptions: the first time an exception is met, leads to the
creation of sub-rules.
Countersigns and nosigns: three kinds of informations
o Signs: all or some of the conditional aspects of the rule met
o Countersigns
o Nosigns
Informational overload: you need to select the information that is
relative.
Rule strengths: the more you use a rule, the stronger it gets,
including partial matches. (thinking stranger is your friend because
of same characteristics)
General rules: are stronger rules. Exceptions are exceptional.
Redundancy: repeated encounters result in ignoring redundant
information, increasing the strength of the remaining cues.
Rigidity: if it isn’t broke don’t fix it. You stick to something that works
in the past.
Rule level errors: application of bad rules
, Encoding deficiencies
Action deficiencies: wrong rules
Error = the failure of planned actions to achieve their desired goals
without some unforeseen or chance intervention (Reason, 1990).
Error types:
1. Errors of Automation = stuff that you do, that you somewhat trained
in, that you do not pay much of attention to.
a. Slips: attention failure, action related
b. Lapses: memory failure, forget
2. Errors of conscious control = mistakes; we have a plan, can be good
or bad, and doesn’t work out to reach our goal.
a. Mistakes: intention failure
b. Violations? Is it an error when you know you have an violation?
Blaming is something we don’t do.
Rasmussen – human performance
Knowledge level: bounded rationality & “thinking” (problem solving)
Rule level: pattern matching & recognition, if… then…
Skill level: highly automated, very little/no effort
Behaviour moves between these levels. Something that you learn can
become skill level after you do it much. Skill level is very energy efficient,
if we would have to think about everything it would be very difficult.
Skill level: e.g. playing guitar, dancing. A lot of things we do in daily life we
could not do without skill level. Makes us respond quickly.
Rule level: e.g. we think a larger country means more inhabitants, but not
always true.
Knowledge level: problem solving and learning (also with animals)
Generic error-modelling system (GEMS)
Skill slips and lapses
Rule rule based mistakes
Knowledge knowledge-based mistakes
,Skill level errors: inattention/omission
Double-capture slips: distracter captures executive control; stronger
automation takes over.
Omissions following interruptions: attention checks fail after an
external event. Attention was distracted so you forgot to do
something.
Delay reduces control: detached intentions, environmental capture,
multiple sidesteps (walking upstairs and forgetting what you’re
doing)
Perceptual confusions: a pattern matching problem. Can have
serious consequences (e.g. gun and taser with police)
Interference errors: control issue, “blends”, “spoonerisms”. (e.g.
answering the phone at home the same way as you do at work as a
secretary). Freudian slip is where you say one thing but mean your
mother.
Skill level errors: over attention
Omissions
Repetitions
Reversals
o Sometimes it’s best not to think about doing something.
o When you don’t want to do something but still do it.
Rule level errors: misapplication of good rules
First exceptions: the first time an exception is met, leads to the
creation of sub-rules.
Countersigns and nosigns: three kinds of informations
o Signs: all or some of the conditional aspects of the rule met
o Countersigns
o Nosigns
Informational overload: you need to select the information that is
relative.
Rule strengths: the more you use a rule, the stronger it gets,
including partial matches. (thinking stranger is your friend because
of same characteristics)
General rules: are stronger rules. Exceptions are exceptional.
Redundancy: repeated encounters result in ignoring redundant
information, increasing the strength of the remaining cues.
Rigidity: if it isn’t broke don’t fix it. You stick to something that works
in the past.
Rule level errors: application of bad rules
, Encoding deficiencies
Action deficiencies: wrong rules
