Human Error in Safety Science

Introduction to Human Error

• Human error as a factor in accidents across industries.
• Became a focus of scientific study after the Three Mile Island nuclear meltdown in 1979.
• Emergence of two schools of thought: Cognitive Psychological School and Joint Cognitive Systems School.

Cognitive Psychological School

• Best represented by Professor James Reason.
• Focus on everyday errors leading to theories of absent-minded slips.
• Developed a taxonomy for high-risk operations errors:
  • Slips: Failures of attention.
  • Lapses: Failures of memory.
  • Mistakes: Rule-based or knowledge-based.
  • Violations: Breaching rules or procedures.
• Error seen as a societal fact and categorizing errors helps explain accidents.

Joint Cognitive Systems School

• Developed by Jens Rasmussen, Erik Holnagel, and David Woods at Rysø, Denmark.
• Focus on real-world, high-risk work rather than a psychological construct.
• Studies error as interactions in complex systems.
• Human error seen as a symptom, not a cause.
• Holnagel's assertion: human error is an analytical dead end.

Implications of Different Views

• Cognitive Psychological School:
  • Targets brain-level system interventions.
  • Focuses on motivation, proceduralization, and task allocation between humans and technology.
• Joint Cognitive Systems School:
  • Analyzes broader system interactions and configurations.
  • Considers the gap between idealized work and actual work.
  • Advocates for understanding complex relationships for system improvements.

Conclusion

• No definitive right or wrong view of human error.
• Importance of narrative in understanding accidents and safety.
• Different stakeholders (e.g., safety managers, journalists) may tell different stories based on their perspectives.