People fail to see an unexpected object in plain view while attention is engaged elsewhere.
Simons and Chabris's 1999 gorilla study: half of viewers counting basketball passes missed a person in a gorilla suit walking through the middle. Radiologists in a later replication missed a gorilla inserted into lung scans.
In practice
- An auditor checking one control walks past the unlocked server room.
- A driver checking mirrors for cars does not register the cyclist, and reports afterwards that the cyclist appeared from nowhere.
- Further reading
- Wikipedia
- Subject
- Psychology & Behavior
- Essay
- A century and a half of measuring the mind