It's a true of every election cycle. The party nominee, including Donald Trump for the Republicans and Hillary Clinton for the Democrats, always meets with U.S. intelligence officers to find out about any pressing issues.

While we don't know the nature of the conversation, it's pretty easy to make a wild guess. The nominee is updated about possible threats to national security, informed about clandestine operations, and updated about any ongoing global crises.

Donald Trump claims he was able to read the body language of the people in the room and determine that the officers were not that happy with President Obama and that he didn't follow their advice. In his own words: "[The President] did not follow what our experts said to do," Trump said this week on NBC. "And I was very, very surprised. I'm pretty good with body language--I could tell they were not happy."

Apart from the politics involved (and whether intelligence officers would even have an opinion like that), Trump revealed a common misunderstanding about how body language works. In any meeting, body language is a sign of engagement, not viewpoint. When someone slumps in a chair and doesn't seem to be interested in the topic, it means that is a person who wants to be somewhere else or is not that tuned in. Like a radio signal, they are tuned to an unknown frequency. They're out of range.

What you can read from someone in a meeting is their signal strength. When people lean forward, put their hand under their chin, and look you in the eye, it means they are fixed on the discussion. When they fold their arms, lean back, look at the door constantly, or keep their head tilted awkwardly to the side, it usually means you have lost them, that they are "somewhere else" in time and space.

It's important to understand what you shouldn't read from body language. Engagement or disengagement do not correlate directly with agreement or disagreement, with acceptance or denial. You just don't know. Maybe the person doesn't like the topic, maybe he or she has a pressing deadline, maybe the person doesn't like you or the meeting or the color of the table (or all three).

Our job in any meeting is to judge engagement and attempt to draw people into the discussion. At that point, you have a chance of persuading them or hearing their view. Body language is a tool, it's an aid. You can only ask--using your words, and listening to what they say--about whether there is some common ground.

Can you tell if someone disagrees with you if they slump or sit frozen in a chair, if the constantly glance at a watch or stand up and pace? Not really. Think of the person who puts his feet outstretched in a chair and leans back, folding his arms back in a repose. Is that agreement or disagreement? You can read if that person is interested. The only way to find out an actual opinion is to ask.

As I've mentioned before, I view this act of "reading body language" as overrated. It's a signpost on the way to speaking and listening. It augments and reflects. You can't determine a viewpoint based on a raised fist. You only know that someone is adamant. You can't determine a viewpoint based on slumping. You can only determine that there is some cause for the disinterest.

Anything more than that isn't body language. It's conjecture.