Cognitive load

Cognitive load describes the effort someone has to spend decoding an image or a sentence before they understand what is on offer. Thumbnails live or die on it. A viewer scrolling a feed gives each one a fraction of a second, and a design with one clear focal subject reads in that window while a crowded one does not. Loading a thumbnail with three faces, four objects, a logo and six words of text does not add information; it hides the information already there. Titles have the same budget, and one that needs a second reading has already spent it.