week 8 - human factors

Question 1

what are the origins of HF

Answer 1

Humans have been designing tools overcome their physical

limitations for a very long time…

Question 2

what have humans chnaged to overcome physical limitations

Answer 2

• Strength: Levers and pulleys to move heavy objects
  • Size: Adapting stones to fit hands
  • Reach: Adding handles to form axes
  • Speed: Horses as transport

Question 3

what are cognitive limitations people have overcome

Answer 3

• Writing: To convey meaning, store/share information
  • Numerical systems: To reduce demands of
  mathematics

Question 4

what are perceptial limitations people have overcome

Answer 4

Telescopes: To see over distances
• Glasses: To reduce eyestrain, increase acuity
• Sunglasses: To limit light exposure

Question 5

What occured in early human factors studies ? (1900’s)

Answer 5

• Time: How fast could each task (and sub-task) be
  performed?
• Motion: What were the fewest motions required for each task (and sub-task)?

Question 6

what was the bricklaying motion study

Answer 6

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

Question 7

define human factors

Answer 7

To design (or engineer) systems while taking
psychological and physical factors into account

Question 8

what are three purposes for desinging a system

Answer 8

• Design has a purpose
  • Design considers a user
  • Design to reduce error

Question 9

what are three goals when designing human systems interaction

Answer 9

1. Enhance performance (productivity)
2. Increase user satisfaction (usability, comfort)
3. Increase safety (error reduction)

Question 10

what is a socio-technical system

Answer 10

• System that includes both social and technical
elements:
• Social: Includes individual and team factors
• Technological: Includes equipment, machines, tools
and technology

Question 11

what are the human elements that psychology can bring to human factors

Answer 11

Sensation and Perception
Attention
Cognition
Decision-making
Stress
Fatigue

Question 12

what are the domains that benefit from psychology

Answer 12

• human capabilities and limitations
• human machine interaction
• team work
• designing tools/technology
• environmental factors
• work and organisational design

Question 13

what are three ways we understand human nature

Answer 13

• error is in our nature
• errors may cause accidents
• errors can be prevented

Question 14

define an accident

Answer 14

A short, sudden, and unexpected event or occurrence that results in an unwanted or undesirable outcome”

Question 15

define human error

Answer 15

“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

Question 16

define erroneous action

Answer 16

“An action which fails to produce the expected result and which therefore leads to an unwanted consequence

Question 17

why do errors occur

Answer 17

1- we dont like to expend too much effort on a task
2- human fallibility
3- limited resources

Question 18

what are the three types of information processing

Answer 18

1- skill based
2- rule based
3- knowledge based

Question 19

what is skill based behaviour

Answer 19

• 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

Question 20

what is rule based behaviour

Answer 20

• 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

Question 21

what is knowledge based behaviour

Answer 21

• 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

Question 22

what are the three types of errors

Answer 22

1- mistakes (errors of perception and interpretation)
2- lapses (failure of storage)
3- slips (incorrect execution)

Question 23

define mistakes

Answer 23

Occur mostly during assessing and planning of
tasks (an unsafe outcome resulting from an unsuitable
plan of action):

Question 24

define lapse

Answer 24

Occur mostly during storage (an internal event

such as a failure of memory):

Question 25

define slips

Answer 25

Occur mostly during task execution (an observable
action, commonly associated with attentional or
perceptual failures)

Question 26

Rule based errors

Answer 26

apply either good or bad rules to come to the incorrect outcome

Question 27

Knowledge based errors

Answer 27

occur in the absence of rules and lead to incorrect outcome

Question 28

what are the three compnents for understanding human error

Answer 28

1- human fallibility
2- context
3- barriers

Question 29

what are contextual factors that might contribute to error

Answer 29

1- work environment
2- equipment/interface deisgn (workspace layout)
3- organisational/social factors

Question 30

define barriers

Answer 30

• 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)

Question 31

how does barriers interact to prevent human error

Answer 31

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)

Question 32

what are some tricky bits of human error

Answer 32

1- Working out whether something was actually an error is not always straightforward
2. Sometimes making errors is good