Design AtlasOne of six persuasion principles psychologist Robert Cialdini laid out in "Influence: The Psychology of Persuasion" (1984). When people are unsure what the right action is, they look at what others are doing — a 4.8-star rating, "1,204 people joined this week," or review photos all work the same way.
Experiments repeatedly show that adding a number or avatar stack next to a signup button lifts conversion on its own. It's genuinely useful when the numbers are real; faked reviews or inflated counts turn it into a dark pattern.
The demo shows a cursor moving faster and more confidently toward the button with an avatar stack and count (B) than the plain one (A).
When to use
Use this near a signup or purchase button — but first verify the number or reviews you display are real and current.