After all, lies will lead to guilty conscience. When exposed by certain language, the fox's tail will eventually show. Take a look at the following methods to catch lies:

1. Use open-ended questions. This forces the liar to make up more lies until he can no longer justify them.

2. Use some assault methods. Investigators should increase the liar's "cognitive load" by suddenly asking him some unintelligible questions or asking him to tell stories in flashback, which are all methods that can make it difficult for him to maintain his composure.

3. Pay attention to some small but verifiable details. If a person says he is at Oxford University, ask him what it was like on the way there. If you do find an inconsistency with the truth, it's better not to expose it right away. It's better to let the liar tell more lies as their confidence grows, rather than correcting them immediately.

4. Observe changes in their confidence. Watch closely the changes in a potential liar's confidence when they are challenged: A liar may ramble on when they think they have the situation under control, but there are limits to this. They may talk when they feel they are losing control of the situation. Gradually became silent.

A small talk, not a tit-for-tat interrogation. In this relaxed atmosphere, the liar may gradually contradict himself or become visibly uneasy and frightened. What we need to realize is that there is no one-size-fits-all method for this process. What we have to do is to find the most appropriate method at each stage of the conversation, and then summarize all the clues together to form a macro judgment.

A friend said that this is like turning conversation into an art, but the effect is good or bad. The research team arranged for multiple fake passengers, all with real tickets and border crossing documents, and spent a week to concoct a travel story. They were then lined up with real passengers, and screeners trained in the method invented by Ormerod and Dando were able to identify 20 times as many fake passengers in only 70 seconds.