First reported by the Nielsen Norman Group from 2006 eye-tracking research. People don't read every word — they scan the headline and first line widely, then narrower lines, then drift down the left edge only. Plotted as a heatmap, it traces an F (or E) shape.
The practical rule: **put the important words at the start of each line/paragraph, and left-align scannable headings and bullets.** This pattern shows up strongly on dense text pages (news, blogs, search results) and weakens on card- or image-heavy layouts.
The red dot below retraces that heatmap path — wide across the top, narrowing, then dropping straight down the left edge.
When to use
Use this when ordering information on text-dense pages like news, blogs, or search results. Front-load the key words in every line.