The authors of your text present evidence that suggest that witnesses who can identify a suspect in a lineup in under are probably more likely to correctly identify the suspect.

The answer is under "ten seconds".

A police lineup is a procedure by which a victim of a crime or witness' accepted recognizable proof of a suspect is affirmed to a level that can be considered as proof at trial. This procedure more often than not includes having the suspect and four or five other individuals line up against a fence.