Human-computer interaction

All systems where a human interacts with a machine are concerned. This encompasses software and website interfaces, mobile applications, the interfaces of embedded systems (car, plane, medical equipment), voice commands, gesture interfaces, and so on. HCI covers a broad spectrum, from the most everyday interface to the most specialised.

Affordance refers to the ability of an interface component to signal the way it should be used. If you take the example of a raised button, it indicates that you can press on it. In the same spirit, underlined and coloured text indicates a link. These affordances let the user understand how the interface works while reducing the learning time. It was Don Norman who popularised this concept, originally drawn from the psychology of James Gibson, and who applied it to interface design.

You can use existing frameworks such as Nielsen's 10 heuristics or the criteria of Bastien and Scapin for a technical evaluation. Otherwise, other, more subjective methods such as user tests or standardised questionnaires make it possible to gather users' feedback. Generally, the quality of an HCI is assessed based both on its effectiveness, its efficiency and user satisfaction.