I have known single mothers with little formal education who lived in the projects, worked menial jobs and somehow managed to raise children with class and integrity. Similarly, I have little faith in academic experts with no track record. You cannot learn this sort of thing in a classroom. Do not misunderstand - studies have taught us a lot and there are experts with valuable insight to offer. If you interview a subject and he breaks eye contact and rolls his eyes up, down, left or right, he may be accessing some area of his brain indicative of deception - or he may be tired, nervous, hungry, scared or prone to do that sort of thing when he simply doesn't know what to say.
Statement analysis involves more than a single aspect of the statement.
You must listen to what the subject says and listen for the things he does not say. For example, interview a person who has spent twenty years in prison. Naturally, they grow to avoid it. Also, in your situation, he may be keying off you. Perhaps you look at him a little more intently when you ask the probative question in an effort to assess his physiological response.