Understanding the role of the human factor in safety critical

systems

Dr Lisa Hinkley

Department of Psychology

Oxford Brookes University

Human Factors Psychology• The study of those variables that influence the

efficiency with which the human performer can interact with the inanimate components of a system to accomplish the system goals– (Proctor & van Zandt, 1994, p.2)

• Human factors works to apply principles of psychology to designing products and creating work environments that boost productivity while minimizing safety issues.

Important Topics in Human Factors Psychology

• Cognitive:– Perception – Attention span– Memory span

• But also:– Social psychological issues– Physical limitations

Human Factors Psychology• Applied to:

– Military technology– Nuclear power plants– Aviation– Automobiles– Medicine

• Safety critical, consequences of error???– Consumer products

• e.g. labelling of produce

– Human-computer interaction• Not necessarily be life threatening – but frustrating!

How?• Use what we know about human information

processing to aid system design:• Examine how users perform task – aid design• Consider every potential user, not just young, tech-

savvy people with perfect vision• Anticipate common mistakes the user might make

and prevent those mistakes• Nothing the user does should result in a

catastrophic error.………Ever• Goal – improve human/machine interaction

• Most of the time, if you make a mistake using a product, it’s a design flaw, not a human flaw

Human Factors & Misperceptions

• Understanding human

factors enables us to

design equipment to

prevent disasters.

• 80% airline crashes

caused by human error

– errors of perception?

Previous Projects• Human Factors in Aviation Security

– DERA & Department of Transport• X-ray screeners – how do they make decision

– re: baggage & passengers• Safety critical – September 11 attacks

– Cognitive factors:• Perceptions, attention, decision making

– Social factors:• Peer pressure, airport bosses etc.

• MR-tutor– provide a computer-based training tool for

neuroradiology trainees.– provide statistical support for the classification

/diagnosis of MR-images of the brain

Bad Icon Design

http://www.baddesigns.com

Remote control

How do you turn down the volume?

The Infamous Ballot

Some human factors issues to consider:1. The side-by-side presentation is confusing.2. No consideration of even minimal visual impairment.3. No consideration of even minimal motor impairment.4. Why is it possible to punch two if you can only vote for

one?5. It presents extraneous information (e.g., the numbers).

Safety Critical???Safety Critical???