week 8 - human factors Flashcards
what are the origins of HF
Humans have been designing tools overcome their physical
limitations for a very long time…
what have humans chnaged to overcome physical limitations
- Strength: Levers and pulleys to move heavy objects
• Size: Adapting stones to fit hands
• Reach: Adding handles to form axes
• Speed: Horses as transport
what are cognitive limitations people have overcome
- Writing: To convey meaning, store/share information
• Numerical systems: To reduce demands of
mathematics
what are perceptial limitations people have overcome
Telescopes: To see over distances
• Glasses: To reduce eyestrain, increase acuity
• Sunglasses: To limit light exposure
What occured in early human factors studies ? (1900’s)
- Time: How fast could each task (and sub-task) be
performed? - Motion: What were the fewest motions required for each task (and sub-task)?
what was the bricklaying motion study
The Gilbreth’s studied how bricks were placed with the aim being to eliminate ‘wasteful’ motions
- reduced number of movements from 18 down to 5
define human factors
To design (or engineer) systems while taking psychological and physical factors into account
what are three purposes for desinging a system
- Design has a purpose
• Design considers a user
• Design to reduce error
what are three goals when designing human systems interaction
- Enhance performance (productivity)
- Increase user satisfaction (usability, comfort)
- Increase safety (error reduction)
what is a socio-technical system
• System that includes both social and technical
elements:
• Social: Includes individual and team factors
• Technological: Includes equipment, machines, tools
and technology
what are the human elements that psychology can bring to human factors
Sensation and Perception Attention Cognition Decision-making Stress Fatigue
what are the domains that benefit from psychology
- human capabilities and limitations
- human machine interaction
- team work
- designing tools/technology
- environmental factors
- work and organisational design
what are three ways we understand human nature
- error is in our nature
- errors may cause accidents
- errors can be prevented
define an accident
A short, sudden, and unexpected event or occurrence that results in an unwanted or undesirable outcome”
define human error
“A generic term to encompass all those occasions in
which a sequence of mental or physical activities fails to
achieve its intended outcome, and when these failures
cannot be attributed to the intervention of some chance
agency
define erroneous action
“An action which fails to produce the expected result and which therefore leads to an unwanted consequence
why do errors occur
1- we dont like to expend too much effort on a task
2- human fallibility
3- limited resources
what are the three types of information processing
1- skill based
2- rule based
3- knowledge based
what is skill based behaviour
- Lowest level of cognitive processing hierarchy
• Little to no conscious attention (bottom-up processing)
• Relatively automatic, routine behaviours - Often ‘automatic’ responses to some environmental cue
eg riding a bike
what is rule based behaviour
• Middle level of cognitive processing hierarchy
• Mix of automatic/conscious processing
• Used to solve ‘trained for’ problems with ‘if-then’ type
associations
- Rules are stored in long-term memory (often based on
past experience)
eg mathematics
what is knowledge based behaviour
- Highest level of cognitive processing hierarchy
• Conscious, only used if skill and rule behaviour
inadequate
• Effortful processing
• We apply this to novel situations - high demand on resources
eg things that you havent encounted before
what are the three types of errors
1- mistakes (errors of perception and interpretation)
2- lapses (failure of storage)
3- slips (incorrect execution)
define mistakes
Occur mostly during assessing and planning of
tasks (an unsafe outcome resulting from an unsuitable
plan of action):
define lapse
Occur mostly during storage (an internal event
such as a failure of memory):
define slips
Occur mostly during task execution (an observable
action, commonly associated with attentional or
perceptual failures)
Rule based errors
apply either good or bad rules to come to the incorrect outcome
Knowledge based errors
occur in the absence of rules and lead to incorrect outcome
what are the three compnents for understanding human error
1- human fallibility
2- context
3- barriers
what are contextual factors that might contribute to error
1- work environment
2- equipment/interface deisgn (workspace layout)
3- organisational/social factors
define barriers
- Barriers are designed to prevent errors or hazardous
events from occurring:
• Different purposes of barriers (e.g. Prevention,
Control, Minimising consequences)
• Different types of barriers (e.g. Physical, Equipment
design, Warning devices, Procedures, Supervision)
how does barriers interact to prevent human error
A barrier might prevent an error
• A barrier might fail entirely
• A barrier partially work (e.g. might reduce the consequence, turning an accident into a near miss)
• Some barriers can be modified by humans (e.g. turning off an alarm)
• How people perceived the barrier is a factor (e.g.
presence of a barrier might encourage negligence)
what are some tricky bits of human error
1- Working out whether something was actually an error is not always straightforward
2. Sometimes making errors is good
