Invisible Gorilla

Simons and Chabris's video in which about half of viewers counting passes missed a gorilla-suited person walking through.

Specifications & Metrics

Observers counting basketball passes by one team often failed to see a person in a gorilla suit stop and thump its chest.
Miss rates rose in the harder attentional condition, tying the blindness to task load rather than stimulus salience.
The 1999 Perception paper became a flagship demonstration of inattentional blindness in and beyond psychology.