Hughes writes that the typical blink rate is nine times per minute, but then he writes that the average blink rate for most of us is twelve per minute. So, which is it...nine or twelve? In any case, when we are calm, focused, interested or relaxed, the blink rate can drop to as low as three times per minute, he says. An increase is a sign of stress, under which conditions, it can supposedly reach upwards of 70 times in a minute! Since it is normally unconscious (making it extremely hard to control) it has the potential to be a very reliable indicator of stress, discomfort, disagreement, interest, focus, etc. But, rather than try to count how often someone is blinking, Chase offers that one can simply observe at the beginning of a conversation whether the other person's blink rate is fast, average or slow; and then notice if and when there is a shift, along with what was going on when the change in rate occurred. He writes, "your immediate goal is to identify what caused the change and act on it."
According to Hughes, a lot of popular knowledge about gestural hemispheric tendency (GHT), especially as promulgated by crime scene investigation (CSI) television shows, is inaccurate. More specifically, Chase writes that observing if someone is looking a specific way as a means of telling if the person is accessing certain types of memories, fabricated memories or outright deceptions is NOT reliable. And yet, he turns right around and says that experts agree there are certain habits regarding eye-movements that are reliable. I take it that what he is saying is that the direction where someone looks for various classes of memories will vary from one person to another, but that it will remain the same for each individual. In other words, the direction in which a particular person will look to access positive memories will be different from the direction in which they look to access negative memories; and this difference will be consistent for that specific guy or gal. He writes that all of us move our eyes to send our mental "file clerk" into the brain to retrieve data (as Chase puts it). However, everyone is different in terms of where they have "organized" those files. EYE HOME So then, accessing our memories and thoughts causes us to look in a certain direction. The "eye home" is where we typically look to access memories and recall information. To establish a "baseline" for each individual, note how that person behaves under normal conditions and circumstances. Once this is done, you will be able to spot critical deviations from it. For example, once you know where someone generally looks for information, you well be able to discern those moments when they are supposedly accessing information, but are actually doing something else. Or if their eye home is at ten o’clock, but they look in another direction when you ask a question that calls on them to access a visual memory, you'll want to note that difference, etc. ONE NOTE OF CAUTION Hughes says that something he has seen across ALL cultures is that if you are speaking with someone about an emotional event or asking them to recall emotional memories, you will regularly see downward eye movement. Strong emotional memories cause us to move our eyes down.
SHUTTER SPEED As with other animals (supposedly), if humans experience fear about something, their eyelids will behave in the same way—they will involuntarily speed up (close and open more quickly) just like a chihuahua. (When it comes to behavior, speed of any kind almost always equals fear.) So then, in a conversation, if you see a change in shutter speed, it can indicate either the presence of or a reduction of fear.