About thirty-five years ago when I first got into law enforcement I began to observe that suspects often ventilated themselves during interviews while the innocent did not. This served me well, not in detecting , but rather, in seeing which questions caused the suspects discomfort such as when I asked, "Where were you last night?" I used it to gauge psychological comfort and discomfort - invaluable in determining the thoughts and feelings of others.

At this point you may be saying, "Ventilators, don't we do that when we are hot?" Yes and then there was Rodney Dangerfield when he was getting "no respect." All true, but principally we do it when something is bothering us or there are issues. What is great about ventilating behaviors is that they occur in real time, there is no delay. A young man is worried that he will miss his flight and he will repeatedly lift up his baseball cap and run his fingers through his hair. Once he is on board, as happened the other day, the behavior stops.

So lets set temperature aside. What would cause us to self ventilate? The list is long: insecurity, doubt, , apprehension, a sense of weakness, vulnerability, or - all the things cause psychological discomfort. So it doesn't matter if we are taking a school test or being asked questions during an interview for a job, ventilators may show up, especially if we feel psychologically distressed.

So here are some to look for and whenever you see them ask yourself, "Is it the room temperature or is there some issue here?":

1 - Look for individuals to run their fingers through their hair multiple times in quick succession. Women incidentally are less like to do so.

2 - People who wear hats will lift their hat completely off the head or angle it upward in such a way as to let in air. Sometimes also followed by running fingers through the hair.

3 - Women ventilate slightly differently than men when it comes to hair. If they have hair down to the neck they will lift up the hair at the nape of the neck brushing the hair upward - an effort to allow air to cool the neck.

4 - Look for individuals under to pull on their shirt buttons or the front of their shirt by lifting it away from the skin. This may be repeated by both hands lifting up the shirt simultaneously just above the pectorals. The lifting of the shirt allows air to flow beneath the fabric cooling the skin.

5 - Pulling at the shirt collar is also often missed when it is done slowly and without much fanfare unlike our comedian friend Rodney Dangerfield who would tug at his neck collar dramatically.

6- I have seen individuals take their shirttail out, undo their pants, and put the shirt back in again, also in an effort to ventilate.

7- It may not look like ventilating, but look for men to lift up or tug on the shoulder pad of their jacket. This pulling action seeks to let in air - which may or may not work because of the amount of clothes.

8- One you may never have thought about, and that is that when we yawn, that sudden burst of air through our very vascular mouth, will also serve to ventilate us (cools our blood like a radiator) as well as pacifies us. Incidentally when you see a baby yawning repeatedly check to see if they are flushed or their face is hot, they may just be communicating it's hot - and yes they could be communicating their tired - either way check on them.

So there you are a few behaviors dealing with ventilation you never thought about and yet we have all done them to relieve us from the heat, but more importantly to relieve stress.

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Joe Navarro, M.A. is 25 year veteran of the FBI and is the author of What Every Body is Saying, as well as Louder Than Words. For additional information and a free bibliography please contact him through www.jnforensics.com or follow on twitter: @navarrotells or on Facebook. You can also read other Psychology Today articles here. Copyright (c) 2012, Joe Navarro.