Attention, memory and perception
Picture superiority effect
People remember pictures better than words, especially after some time has passed.
Images are stored both as a picture and as a description, which gives memory two ways back to them. Words alone get one.
Pair key ideas with a clear image: an illustration for an empty state, a diagram for a process, a screenshot in a help article.
In practice
An onboarding screen that shows what the dashboard will look like with data in it is remembered better than a paragraph describing it.
Common mistake
Decorative images that carry no meaning. They take attention without helping memory, and can make real content look like an advert.
Where it comes from
Roger Shepard showed in 1967 how well people recognise pictures they've seen, and Allan Paivio's dual coding theory (1971) explained why. Douglas Nelson and colleagues named the effect in 1976.