One of the most famous—and least understood—aspects of Neuro-Linguistic Programming. When a person first thinks about something, their eyes will instantly dart to the left or right and either high, low, or to the middle. This can indicate whether the memory is visual or aural and whether they are actually remembering it or creating it in their minds. This has been called a type of lie detection, but that is inaccurate. For example, merely because someone is creating a visual thought doesn't mean that they are creating a lie. It could simply mean that they need to recreate the thoughts they were having when they saw something in order to remember it. So just looking at a person's eye accessing cues won't tell you if they are lying.
So what good are they? First, you ask a person several questions to see how they naturally respond. This procedure is called calibration. Then, when asking questions about the issue where the person is seeking change or clarity, you can determine their mode of thinking and how to be more effective in your work with that person.