Answer: The technique is called "FLASHBACK"
Explanation: A flashback is an interrupting event in a progressive scene, that helps to narrate a point in the progressive scene. Flashback is normally used when an event in a story does not correspond to the progressive outcome of that story, flashback is use to relate the actions in a scene to a cause.
For example, in a movie or novel, where a lady doesn't like associating with men, flashback can be used to relate her actions to a cause. Maybe she has been raped or cheated by men.