Fluency
n. With ease and gracefulness in unfolding time.
Experiencing fluency puts the user in a positive mood and instills a sense of familiarity and effortlessness – even when an experience does contain difficult or unfamiliar elements. For instance, Clear and crisp fonts are easy on the brain, while graceful swirly typography is not. Short words and paragraphs stimulate fluency as well, while sturdy walls of text do not. It’s all about the psychology of text.
Fluency also is the users feeling of mastery with an interface or set of circumstances. The student fluent in university systems can effortlessly process a course add/drop, or knows where to go to get resources. A driver might slowly acquire fluency as they get used to a new set of automobile controls. Being able to skip the currently playing song without looking while driving, or instinctively moving their hand to the turn signal or gearshift.