What is Human-Computer Interaction (HCI)?

Human-Computer Interaction (HCI) is the discipline that studies how people use computing systems and designs those systems so they fit human bodies, minds and situations. It sits between computer science, cognitive psychology, design and the social sciences, and it produces three kinds of output: knowledge about how people perceive, think and act with technology; methods for observing and evaluating use; and new interaction techniques and devices. When a gesture feels natural on a headset, when a menu is found without thought, or when a public installation is understood by a child in two seconds, HCI research is usually behind it.

The field matters to a studio like VeleStudio because XR and spatial interfaces have no established conventions to lean on. Every project must answer, with evidence rather than taste, how a person should point, select, move, read and rest in a space that is partly real and partly rendered.

A short history

HCI grew up with interactive computing itself.

• 1960s: Ivan Sutherland's Sketchpad (1963) showed direct manipulation of graphics with a light pen, and Douglas Engelbart's 1968 demonstration introduced the mouse, windows and hypertext to a public audience.
• 1970s: Xerox PARC developed the graphical user interface, the desktop metaphor and WYSIWYG editing that shipped in the Xerox Star and, later, the Macintosh.
• 1980s: HCI became a named field. The first CHI conference was held in 1982, and Card, Moran and Newell's The Psychology of Human-Computer Interaction (1983) brought cognitive models such as GOMS to interface design. Don Norman's work on affordances and mental models reached a wide audience later in the decade.
• 1990s: Jakob Nielsen's usability heuristics gave practitioners a cheap evaluation method. Mark Weiser's vision of ubiquitous computing (1991) and Hiroshi Ishii's tangible bits (1997) pushed the field beyond the desktop and into rooms and objects.
• 2000s onward: Paul Dourish's Where the Action Is (2001) framed embodied interaction. Touch, mobile, voice and now spatial interfaces each reopened basic questions about input and attention.

HCI vs UX vs interaction design

The terms overlap but are not the same thing.

• HCI is a research discipline. It asks general questions (how fast can people select targets of a given size, how does latency affect the sense of presence) and answers them with experiments and field studies. Its outputs are models, principles and techniques.
• User experience (UX) is a professional practice concerned with the overall quality of a person's encounter with a product or service. UX borrows HCI methods and findings and adds business and content concerns.
• Interaction design is the craft of shaping the moment-to-moment behaviour of a system: what happens when you press, drag, look, speak or step. It is the part of UX that HCI research informs most directly, and the craft we apply to spatial and physical systems.

A rough analogy: HCI is to interaction design what materials science is to architecture.

Core methods

HCI's lasting contribution to practice is a set of methods for finding out what people actually do, rather than what they say or designers assume.

Contextual inquiry

Observing and interviewing people where the activity happens: in the workshop, on the gallery floor, in the street. For spatial projects this is irreplaceable, because the environment is part of the interface.

Prototyping at several fidelities

Paper, cardboard, bodystorming (acting out an interaction in the real space with props), video prototypes, Wizard of Oz studies where a human simulates the system, and finally working software on the target device. Each level answers different questions at a different cost. We describe our approach in how to prototype an XR experience.

Usability studies

Structured sessions in which representative people attempt realistic tasks while observed, measuring task completion, time, errors and self-reported effort. Five to eight participants per round find most serious problems; several small rounds beat one large one.

Heuristic evaluation

Experts review a system against established principles (visibility of system status, match with the real world, error prevention, recognition over recall) to find problems cheaply before testing with people. For XR we add comfort, safety and spatial-attention heuristics that desktop lists lack.

Quantitative and physiological measures

Fitts's law for pointing, reaction and completion times, head and gaze tracking, and questionnaires for presence, workload and simulator sickness. These make comparisons between design alternatives defensible.

Photo: Zuko.io Images · CC BY 2.0

Why HCI matters more for XR and spatial interfaces

Desktop and mobile interfaces have decades of conventions. Spatial interfaces do not, and they add difficulties that make research non-optional.

Embodiment

In XR, the body is the input device. Reach, height, handedness, the weight of a headset, the fatigue of holding a phone up and the social awkwardness of gesturing in public all shape what people can and will do. HCI research on embodied interaction, proxemics and gesture gives a vocabulary and findings to design from.

Input without conventions

Should selection be a pinch, a dwell of the gaze, a voice command, a controller button or a tap on a phone? Each has measured strengths: gaze is fast but imprecise and tiring to hold; pinch is reliable but needs hands visible to cameras; voice is powerful but fails in noisy galleries and embarrasses people in quiet ones. Choosing without evidence is guessing.

Comfort and safety

Latency, frame rate, vergence-accommodation conflict, field of view and locomotion technique all affect whether people feel sick or strained, and HCI and human-factors research has measured these effects for thirty years. An interface that ignores them is not merely unpleasant; it can make a person fall or walk into traffic.

Attention in an unbounded display

There is no screen edge. HCI work on peripheral awareness, notification and spatial audio tells us how to draw attention without startling or overloading. This is the heart of what we call spatial UX.

How a studio applies HCI research in commercial projects

HCI is sometimes seen as academic and slow. Applied well, it prevents the expensive mistake of building the wrong thing. At VeleStudio we fold it into projects in four ways.

1. Research framing. Each project starts with the question the experience must answer for people, and a short review of what is already known; published findings on comfort, input or wayfinding often settle debates in an afternoon.
2. Early field observation. A day on site watching how people move, pause, look and hold their phones, before any concept is fixed.
3. Prototype-and-measure loops. Low-fidelity prototypes in the real place, then device prototypes, each tested with a handful of people and a few agreed measures. Our human-computer interaction service describes this cycle.
4. Self-initiated R&D. We run studio prototypes to study questions clients cannot afford to explore on their timelines. The presence field installation prototype investigates how people respond when a space reacts to their position and movement; the spatial conversational guide explores how a voice assistant should behave when it can see what the person sees. Both feed directly into client work.

The result is not a report but a set of design decisions with evidence behind them: where content sits, which gesture selects it, how long a session should run and what happens when things fail.

If you are planning an interface that lives in a physical space and want it grounded in how people actually behave, talk to us.