I don't know about you but I cough when theres a tickle in my throat and thats it. However we've all heard the "Just Making You Aware That I'm Here" voluntary attention cough; some of us may even do it. Yes, even you! I'm here to expose it because its annoying as fuck and it happens just about everyday.
The "I'm Here" cough normally comes from a person who thinks you haven't noticed that they've entered your immediate vicinity. These people are unaware of something called peripheral vision and being generally aware of your surroundings and not just the view from the tip of your nose.
The primal "I'm Here" cough announces your existence to other creatures in the wild and attracts attention; its the large print way of warning someone that they are not alone; it's pathetic really.
I've heard the "I'm Here" cough in bathroom stalls as if to say "Just letting you know I'm in the toilet five stalls down from you so don't do anything weird thinking you're alone in here".
Sometimes the "I'm Here" cough is fired off as a warning to possible intruders letting them know they aren't alone and that someone is in the house. For instance maybe you'll even fire off a "Just Making You Aware That I'm Here" cough to alert your roommate when he walks in with his girl late at night.
"Coughing is not always involuntary, and can be used in social situations. Coughing can be used to attract attention, release internal psychological tension, or become a maladaptive displacement behavior. "A few friends of mine employ the nervous cough/yawn thing and I think they actually picked it up from each other. Instead of an awkward silence during a conversation they'll oft fill the void with a yawn to signal a subject change or maybe that they're bored and winding down and getting ready to move on; it's really quite weird. Human beings are so fucking peculiar.
"Social coughs can at times also become ambiguously provocative--this is due to (as with all other forms of human behavior) not being able to discern the motivation behind the behavior or cough - whether or not the cough was truly involuntary. Either way, an unexpected, loud, sharp cough may catch an unsuspecting listener by surprise and jolt the listener, and/or distract and break the listener's concentration. This can be a source of great annoyance (or a source of great joy for the perpetrator) in an otherwise quiet environment (e.g. work environment, library, classroom, computer lab, ...etc).
It is believed that the frequency of such "attack coughs" increases in environments vulnerable to psychological tension and social conflict. In such environments, coughing may become one of many displacement behaviors and/or defence mechanisms. "
So the next time someone coughs behind you, stop and turn around and tell them: "Yes. I am aware you are now here. You are not sick. There was no need for the fake cough to alert me. Thank you."