The Shape of the System - Engineering for Bounded Cognition
a day ago
- #human-factors
- #software-engineering
- #cognition
- The human mind can only hold about four separate things in working memory at once, not the commonly cited seven.
- Software systems consist of millions of lines of code, creating a vast gap between the mind's limited capacity and the complexity it must manage.
- Attention is narrow, akin to a torch beam, leading to inattentional blindness (e.g., missing a gorilla in a video) and change blindness (e.g., not noticing a person swap).
- Information in working memory decays quickly without rehearsal, within about 20 seconds.
- Incidents often blamed on 'human error' are usually failures of system design, not individual carelessness, as systems are built for an idealized, infallible operator.
- Large language models exhibit similar bounded cognition, with limited context windows and uneven attention, performing worse when key information is in the middle of long inputs.
- Engineering solutions address this gap by externalizing knowledge: using precise names, boundaries, tests, and undo functions to move information out of fragile minds.
- Designing for constrained users (e.g., arthritis-friendly tools) often results in better products for everyone, analogous to building software for tired or distracted engineers.
- Effective engineering is a habitual mindset that treats attention as scarce and unreliable, focusing on how small minds can safely change large systems.