UX Glossary · H
Human-computer interaction
Also: HCI
The academic field studying how people use computing systems, and the source of most of UX's evidence base.
Human-computer interaction is the research discipline concerned with how people interact with computing systems. It emerged as a named field in the early 1980s, drawing on cognitive psychology, computer science and human factors engineering. The ACM CHI conference, running since 1982, is its main venue.
Why practitioners should care
Most of what UX treats as received wisdom originated as HCI research, and knowing which claims have evidence behind them is the difference between a defensible recommendation and a preference.
Fitts’s Law is measurement, not opinion. Cognitive load theory comes from decades of experimental work. The “five users finds most problems” claim comes from a specific 1993 model by Nielsen and Landauer, with specific assumptions that are frequently ignored when it is quoted.
Equally, some widely repeated design claims have thin support. Knowing which are which is professionally useful, particularly when a stakeholder disagrees.
HCI and human factors
Human factors engineering is the older and broader parent, concerned with human performance in any system including aircraft cockpits and control rooms. HCI is the branch that focused on computing. In safety-critical domains the human factors framing usually dominates, because the failure modes are physical.
In practice
When a design claim is contested, the useful question is what evidence it rests on. Some have decades of it; some have a blog post.