Impulsive UX: A world of plane crashes and radiation overdoses

Many things can go wrong in high-risk systems. To prevent these errors, it’s crucial to apply our understanding of human behaviour to the systems people utilise. In this discussion, we’ll look into two significant case studies: Therac-25, a computer-controlled radiation therapy machine, and Air Inter Flight 148, a scheduled passenger flight. These distinct events underscore the significance of integrating human behaviour knowledge into system design.

Usability Heuristics

If you are a UX designer then you will probably be familiar with Nielsen's (1994) list of usability heuristics for interaction design.

Let’s talk about a few of these:

• Visibility of System Status: Users should always be informed about what is happening through appropriate feedback within a reasonable amount of time.
• Match Between System and the Real World: The system’s language and concepts should match the user’s mental model and real-world experiences.
• Error Prevention: The design should aim to prevent errors by making it difficult for users to make mistakes or choose incorrect options.

User testing and feedback are essential to guarantee practical usability in real-world situations. However, the true importance of these heuristics becomes strikingly apparent when the consequences of their absence come to light.

Dual Process Theory

As usability heuristics highlight the importance of matching users’ mental models, we will look further at one of these models.

The dual process theory has been developed and expanded upon by various psychologists, including Keith Stanovich, Richard West, and Jonathan Evans. This model divides thinking into two main processes: “System 1” and “System 2”. These terms are used to describe two distinct modes of cognitive processing that our brain engages in.

Let’s talk about these terms:

• System 1 (Immediate/Routine Thinking): This thinking is fast, automatic, and operates largely…