Cognitive fluency describes our preference for information that is easier to process over that which is more difficult to understand.
In UX design Cognitive fluency (sometimes called Processing Fluency) is influenced by the mental effort we need to invest in understanding a concept. This mental effort can be the sum of any number of factors including:
- Past experiences/familiarity – Skeuomorphism used as an aid to imply an element’s function
- Current context – the amount of effort we invest in retrieving information would be greater on a cluttered UI, than on a clean UI, and greater on a difficult-to-read font than easy-to-read.
Cognitive fluency can be cultural, or influenced by experience however – for example a phone dialler UI which uses the metaphor of a rotary dialler to imply its function wouldn’t necessarily be helpful to a user who has no knowledge or experience of rotary phones, or is not already familiar with that metaphor.
In summary, the less effort it requires, and the more familiar it is, the more likely we are to have a preference for it, trust it, engage in it, and use it.