Estimate

you’ll see them for 2.5 seconds. how many?

flash-count a dot cloud, then see how far people typically undercount

A glance is not enough time to count a scattered group, only to guess, and most guesses land under the true number, a common bias in how people size up scattered quantities quickly. The comparison spread shown afterward is a modeled curve built around that tendency, not a record of other people's actual answers.

Concepts: probability, perception.

An interactive you play with one thumb, on Wundr.