See also #usable.

Definitions:

Capability of a user interface to enable pleasing and satisfying interaction for the user

Derived from ISO-25010-2011

Perceptions of web site aesthetics consist of two main dimensions: classical aesthetics — an orderly and clear design (clean, well organized, symmetrical) — and expressive aesthetics — the designers’ creativity and originality, the ability to break design conventions.

Derived from Lavie & Tractinsky 2004

Lineage in the ISO quality models

The term has been renamed twice. ISO 9126 called it attractiveness; ISO 25010:2011 called it user interface aesthetics; ISO 25010:2023 replaced it with user engagement. Each rename shifted the focus a little further from the means (how the interface looks) towards the objective (whether people keep using it).

Not the same as user engagement

This site keeps aesthetics and engagement as separate qualities, because they sit at different points of a cause-and-effect chain:

  • Aesthetics is a perceptual property: how the interface looks and feels at the moment a user sees it. It is judged before any sustained interaction takes place, and it is measured by looking — with aesthetics scales, expert review, or comparisons of visual variants.
  • Engagement is a behavioural outcome: whether users keep interacting, return, and recommend the product. It is measured over time — with session length, return rate, or questionnaires such as the User Engagement Scale.

The research literature treats aesthetic appeal as one contributor to engagement, alongside focused attention, novelty, felt involvement and perceived usability (O’Brien & Toms 2008). A part cannot be a synonym for the whole. The two can also exist without each other: a beautiful dashboard that nobody opens twice is aesthetic but not engaging; a plain command-line tool that people use daily is engaging but not aesthetic.

Aesthetics also influences how usable a product appears to be: users rate attractive interfaces as easier to use even when they are not — the aesthetic-usability effect first shown by Kurosu & Kashimura in 1995.