Based on a person’s job, geographical location, age, etc., investigators should have a basic idea of the breadth and depth of information that such a person should know.
When answers show that someone does not have the expected level of information (too much or too little or different information than expected), this may be an indicator of deceit.
In an extreme case, if someone is interrupted in the middle of a statement on a given topic, they will have to start again at the beginning in order to “get the story straight.”
Often if someone plans on lying about a topic, they will memorize or practice exactly what they are going to say.
If they always relate an incident using exactly the same wording, or answer ‘repeat’ questions identically (word for word) to the original question, it may be an indicator of deceit.