Uploaded by Faris Harun


Human Factors
Indicators of Human Factors
• Accidents where “human error” is a cause
• Occupational health reports of mental or physical
• High absenteeism or sickness rates
• High staff turnover levels
• Low level of compliance with h&s rules
• Behaviour issues identified in risk assessments
• Complaints from staff about working conditions
or job-design
Common Human Failures in
• Job Factors:
Illogical design of equipment & instruments
Constant disturbances or interruptions
Missing or unclear instructions
Poorly maintained equipment
High workload
Noisy & unpleasant working conditions
Common Human Failures in
• Individual Factors:
Low skill & competence levels
Tired staff
Bored or disheartened staff
Individual medical problems
Common Human Failures in
• Organisation & Management Factors:
Poor work planning, leading to high work pressure
Lack of safety systems and barriers
Inadequate responses to previous incidents
Management based on one-way communication
Deficient co-ordination and responsibilities
Poor management of health & safety
Poor health & safety culture
Human Failures
• Errors (not intended)
– Slips
– Lapses
– Mistakes
• Violations (deliberate)
– Routine
– Situational
– Exceptional
• “Actions-not-as-planned”
• Examples:
– Performing an action too soon in a procedure
– Carrying out an action with too much or too
little strength (e.g. over-torquing a bolt)
– Switching the wrong switch
– Moving switch up rather than down
– Carrying out the wrong check on the right item
Forgetting to carry out an action
Lose our place in a task
Can be due to interruptions or distractions
– Forgetting to fill switchgear with oil?
• Doing the wrong thing, believing it to be
• Consist of:
– Rule-based
– Knowledge-based
Routine Violations
• Breaking the rule has become a normal way
of working within the work group. This can be
due to:
Desire to cut corners to save time & energy
Perception that rules are too restrictive
Belief that rules no longer apply
Lack of enforcement of the rule
New workers starting a job where routine
violations are the norm and not realising that
this is not the correct way of working
Situational Violations
• Breaking rule is due to pressures from the
job such as:
being under time pressure
insufficient staff for the workload
right equipment not being available
extreme weather conditions
Exceptional Violations
• Rarely happen and only then when
something has gone wrong
• To solve a new problem you feel you need
to break a rule even though you are aware
that you will be taking a risk
Influences on behaviour at Work
• The study of what makes each of us a
distinct person
• Some characteristics are shared by all
human beings
• Each person is different in some respects
• A person’s point of view, or their way of
looking at something
• Influences the way a person reacts in a
certain situation
• Both good and bad attitudes are
Attitude Formation
• Attitudes are primarily dependant on:
Early childhood
Progress (or the reverse)
• A person’s talent for doing something
• Education should give knowledge and help
to form correct attitudes, while training and
practice are necessary for aptitude
• That which makes an individual act as they
do - their reason for doing something
• A drive can be either:
– Appetitive - towards something we want
– Aversive - avoiding something unpleasant
• An event that is followed with reward is
likely to recur (positive reinforcement)
• An event that is followed with punishment
is likely to desist (negative reinforcement)
• With increasing experience we expect more
competence and an increase in ability to
cope with situations
• However, there is a tendency to cut corners,
as shown in the graph:
• There needs to be enough mental
stimulation, but not too much
• A person with low intelligence may find
even a routine, mundane job very taxing
• If a person of high intelligence is set a
mundane task, he will probably employ
himself in finding new and less arduous,
but not necessarily safer, ways of
completing a task
Sensory Defects & Screening
• Sensory defects increase with age and
failing health
• We screen out things we are not interested
in or consider not worth listening to
• We can go into “auto-pilot” mode, which
saves effort and allows us to concentrate
on other things, or think ahead. This is
useful, but causes many accidents
Perception of Danger
• Factors involved in perception:
– Signals from sensory receptors
– Expected information from memory
• Signals from sensory receptors and
memory can be misleading, particularly if
we are affected by stress, alcohol, drugs,
fatigue or just familiarity
Perceptual Set
• Also called a “mind set”
• When we have a problem, immediately we
perceive not only the problem, but the
• Further evidence may become available
which sows our original perception to be
faulty, but we are so busy congratulating
ourselves on our intelligent solution that
we fail to see alternative causes &
Perceptual Distortion
• Perceptions get distorted
• Things which are to our advantage always
tend to be more right than those which are
to our disadvantage
Errors in Perception Caused by
Physical Stressors
• Consider effects of:
stress from work and home
• Shift work is a major factor
• Our bodies operate best when we have a
regular routine
Perception and the Assessment
of Risk
• In assessing a risk, there is safety in
• One persons faulty perception of a risk
could be corrected by another persons
clearer perception
• Perception also depends upon knowledge
& experience - a group will have more to