Inattention

Inattention is a situation when someone fails to pay attention to someone or something and as a result some information is missed which later turns out to be significant. Quite often a witness is trying to say something important but is dismissed because the listener is too busy, or distracted, or simply does not regard the speaker as important enough to listen to. At times there is no opportunity to recover what was missed because the witness has been killed or is not longer available.

Inattention as a plot device in the works of Agatha Christie

 * Cat Among the Pigeons - Miss Bulstrode fails to pay attention to what Mrs Upjohn is saying and later has the feeling that she has missed something significant.
 * The Clocks  - Edna Brent tries to tell the police that someone at the inquest must have been lying. She is not listened to and is later killed.
 * A Murder is Announced - Just when Miss Hinchcliffe os about to leave the Boulders, Miss Murgatroyd exclaims: "She wasn't there!". Miss Murgatroyd doesn't pay her any attention and misses Amy's intonation.