Human factors lecture 3pp


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Human factors lecture 3pp

  1. 1. 1 INTRODUCTION TO HUMAN FACTORS Dr Nathan Perry 101183 Behavioural Science What is Human Factors?  Understand human interactions with a system  Factors that influence human performance What is Human Factors? Human Characteristics Task Characteristics Environment Attention capacity Workload Illumination Working memory capacity Level of training Noise Expertise Display design Vibration Communication skills Organisational Culture Climate Personality Technological reliability Altitude
  2. 2. 2 Human Error Shooter A Shooter B Variable Error Constant Error Reason (1990) Information Processing Information Processing Wickens & Carswell (2006) Information Processing Errors  Slips  Not Deliberate  Failure of attention  Lapses  Not Deliberate  Failure of memory  Mistakes  Deliberate  Wrong course of action Reason (1990)
  3. 3. 3 Perception Question You are designing a new phone book. Which of the following formats would you choose? (a) Nathan Perry 97726139 (b) Nathan Perry 97726139 Cognitive Factors Perception Definition: Extraction of meaning from information Processes 1. Bottom-up processing 2. Top-down processing Cognitive Factors Perception Bottom-up processing  Analysis and integration of features  Characteristics  Slow  Effortful  Does not require experience Cognitive Factors
  4. 4. 4 Perception Top-down processing  Perception shaped by previous experience  Recognition of the whole  Characteristics  Fast  Relatively automatic  Requires previous experience Cognitive Factors Perception: Human Factors Implications  Feature degradation reduces ability for bottom-up perception Top-down processing still possible with degraded features Cognitive Factors Perception: Human Factors Implications  Display of information  In context: words perceived top-down  Random numbers: perceived bottom-up  If display provides both text and numbers  display numbers in larger font to aid bottom-up Wickens et al. (2004) Cognitive Factors
  5. 5. 5 Perception Question You are designing a new phone book. Which of the following formats would you choose? (a) Nathan Perry 97726139 (b) Nathan Perry 97726139 Wickens et al. (2004) Cognitive Factors Perception Cognitive Factors Cognitive Factors Perception
  6. 6. 6 Cognitive Factors Perception Cognitive Factors Memory Working Memory: Short-term memory store which enables the manipulation of information Long-Term Memory:prolonged storage of information for later retrieval Cognitive Factors Memory: Human Factors Implications  Working Memory: Processing requirements exceed working memory capacity  performance decline  Long-term memory: Inability to retrieve information
  7. 7. 7 Cognitive Factors Working Memory Rail Control Example Cognitive Factors Decision-Making Definition: Choice between alternative options or courses of action Theorised to involve: (a) Information acquisition (b) Information interpretation (c) Planning and selecting choices Cognitive Factors Decision-Making  Use a range of different decision strategies Simple Complex
  8. 8. 8 Cognitive Factors Decision-Making Situation Simple or Complex Requires Accuracy Complex Little Time Available Simple Vast amount of information Simple Little Task Experience Complex Cognitive Factors Decision-Making: Expertise  Interviews with expert Fire Ground Commanders  Don’t compare and contrast decision options  Recognise the situation  Use cues present in the environment to recall similar situations from memory  Use strategy taken in previous situation Klein (1989) Cognitive Factors Decision-Making: Human Factors Implications  Tendency to limit info. analysis  Effortful & time-consuming  Reduced potential for accuracy  Implement systems to reduce effort associated with info. analysis Perry et al. (2012)
  9. 9. 9 Cognitive Factors Decision-Making: Human Factors Implications  Display critical information  Advises on a course of action  Determines and executes course of action Traffic Collision Avoidance System (TCAS) Climb! Climb! Descend! Descend! Cognitive Factors Attention  Information processes require attention  Limited attention capacity  Cannot attend to everything  Without attention  information unlikely to be processed Cognitive Factors Attention: Human Factors Implications  Attention required for info processing  Ensure that operators attend to crucial information  Design systems to ensure attention is given to crucial information
  10. 10. 10 Design Lever underneath seat in van Q: What will happen if the lever is pulled? A: Seat detaches from floor Design A: Mop sink Design
  11. 11. 11 Design System Design  Airbus A320 accident in Strasbourg 1992  Pilot engaged behaviour that was inappropriate for current mode  Appropriate for different mode  Preparing to land – autopilot  Needed change flight angle to 3.3 degrees  Flight management system set in the vertical speed mode  Pilot dialled 3.3 into flight control unit  In this mode this meant a speed of 3300 feet per minute!  Instead of 800 feet per minute Overreliance on Automation  Role of human operator with automated system is often to monitor  Humans have a tendency to put a lot of trust in automated systems  Out-of-the-loop performance problem  Automation Induced Complacency  Automation Bias  Skill Loss
  12. 12. 12 Automation-Induced Complacency System Monitoring Tracking Fuel Management  Parasuraman et al. (1993) Task  Computer-based flight simulation  Participants task to detect automation failures  Reliability of automation manipulated  Constant vs. Variable 0 0.2 0.4 0.6 0.8 1 1 2 3 4 5 6 7 8 9 10 11 12 Constant Variable Total Automation Failure 0 Probabilityofdetecting systemmalfunction Trial Block Modified from Parasuraman et al. (1993) Automation-Induced Complacency Reliability Automation-Induced Complacency Automation: Human Factors Implications 1. Keep the operator informed 2. Keep the operator trained 3. Keep the operator in the loop 4. Select appropriate levels of automation Wickens et al. (2004)
  13. 13. 13 Accident Causation Reason (2000) Summary  Human factors issues are complex  Role of human factors specialist  Facilitate the fit between humans and the system  Role of psychologist  Consider the psychological issues to ensure fit between humans and system