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Copyright Catherine M. Burns
1
Situation Awareness
Copyright Catherine M. Burns 2
What is Situation Awareness (SA)? Awareness of the meaning of dynamic changes
in the environment “Perception of elements in the environment
within a volume of time and space, the comprehension of their meaning and the projection of their status in the near future” (Endsley, 1995)
Copyright Catherine M. Burns 3
Stages of SA
Perception Understanding Prediction
Copyright Catherine M. Burns 4
Power Grid Failure
“Lack of Situation Awareness” as a root cause
Copyright Catherine M. Burns 5
Measuring SA
SAGAT (Situation Awareness Global Assessment Technique Operator performs a complex task Periodic interruptions Asked SA questions
Location of other peopleLocation of hazards
Copyright Catherine M. Burns 6
Decision Making
Perception Understanding PredictionDECISIONMAKING
Wickens Ch7
Copyright Catherine M. Burns 7
Decision-Making Tasks
A decision making task is a task where a person selects one choice from a number of
choices there is some information available on the
choices the time frame is relatively long (1 sec) there is some uncertainty
Copyright Catherine M. Burns 8
Tasks
medical diagnosis flight judgements process control fault diagnosis safety-related behaviour
Copyright Catherine M. Burns 9
Normative vs Descriptive Models
Normative specify what people should ideally do, utility
Descriptive describe what people actually do descriptions of what can influence decision
making
Copyright Catherine M. Burns 10
Normative Methods
Multi-attribute utility theory Expected value theory Subjective expected value theory
Copyright Catherine M. Burns 11
Multi-Attribute Utility Theory
U(v)=i=1
n
a(i)u(i)
The sum over all attributes of the magnitude of each attribute multiplied by its utility
A way of comparing alternatives that have many different dimensions
Copyright Catherine M. Burns 12
Car Example in Text
You’ve weighted the various car attributes as follows: Engine performance 8 Brake performance 5 Styling 4 Seat comfort 2 Floor mats 1
Copyright Catherine M. Burns 13
Car example
You are considering the following cars 2004 Mazda 3 2002 Honda Civic 2003 Ford Focus 2004 Honda Civic
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The cars rate as follows:
Styling Brakes Seats Mats Engine Score
Utility 4 5 2 1 8
M3 3 3 9 3 1 56
H2 3 3 3 3 3 60
FF 9 1 3 1 9 120
H4 1 3 9 9 9 118
Copyright Catherine M. Burns 15
Expected Value Theory
determines the value of various outcomes under uncertainty
assumes people should pick the highest value outcome
probabilistic “gambling” type questions p=0.2 of winning $50 E=0.2x$50=$10 p=0.6 of winning $20 E=0.6x$20=$12 People should pick option two
Copyright Catherine M. Burns 16
Problem with Expected Value Theory
People don’t actually make the “optimal” choice
Values on outcomes can be subjective, different for different people
Subjective Expected Utility Theory
Copyright Catherine M. Burns 17
SEUT
Assigns a subjective utility value, instead of the objective value used in EVT
Basic idea is still probability (p) x utility (u) highest expected utility is the best decision
Copyright Catherine M. Burns 18
Descriptive Models
Mostly isolate effects that can influence decision making
Understand why human decision making doesn’t follow normative models
Copyright Catherine M. Burns 19
Descriptive Models
Satisficing: People look for the first solution that meets the criteria, not the optimal solution Used when there are a large number of potential
alternatives, limited time Simplifications, heuristics and biases
People create easier ways of thinking about things
Copyright Catherine M. Burns 20
Heuristics and Biases
Three stages: 1. Getting information input (cues) 2. Generating hypotheses 3. Plan generation and action choice
Copyright Catherine M. Burns 21
1. Cue Perception and integration
Input or Cue Biases : People pay attention to a limited number of cues, Early information is more influential (cue
primacy), Late information is underweighted, Very visible cues are given more weight, Overweighting of unreliable information.
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2. Hypothesis Generation and Selection
Biases: People only generate a small number of hypotheses Most frequently seen hypotheses are preferred
(availability heuristic) Minimal information gathering if there is a strong cue
match (representativeness) Overconfidence. Tend to think they are more correct
than they really are. Cognitive Tunneling: Reluctance to change from a
hypothesis Confirmation bias: Tendency to only look for confirming
information.
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Biases in Action Choice: Retrieving a small number of actions Retrieving the most frequent or recently used
actions Evaluation or estimation of the likely outcomes
of actions Framing bias: presentation of problem affects the
decision
3. Action Choice
Copyright Catherine M. Burns 24
Special Case of Framing Bias
“Sunk Cost Bias” Investors who resist selling losing stocks even
when the long term better choice is to sell
Copyright Catherine M. Burns 25
The SRK Framework
Suggests people have to make three categories of “decisions” 1. automated or skill based decisions 2. procedural or rule based decisions 3. knowledge based decisions
Depends on familiarity of the situation and experience of the person
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Decision Support
Often aim to reduce decision making biases make relevant cues more salient suggest alternative courses of action provide additional information, especially
disconfirming information show realistic simulations of decisions Simulation, expert systems and displays
