People laugh because they are genuinely happy or they laugh to try to make light of their extreme discomfort. The latter may be an attempt to convince themselves or others that what happened wasn't such a big deal after all, or to try to smooth things over and distract when there is a tense situation, or it could be a way of trying to say that they don't really care how stupid they feel even if they do. For some types, they have found that if they can laugh about something, it helps them move on from those negative feelings much faster, and in that sense it can be healthy.
My grandmother used to laugh just to fill in the blanks in conversation:
G: Well, how have you been? Ha ha ha ha
Me: Things are going really well Grandma. I just got back from Edmonton.
G: You did? Ha ha ha ha
Me: Yeah, I was staying at Leroy and Shirley's. They had the kids out for a visit too.
G: Well then. Ha ha ha ha
I think it was her discomfort, but the laughter itself gave you the impression that she wasn't really listening to anything you said, or that you could tell her your mother died and she would still laugh.
I think sometimes in the sense that hommefatale is talking about, it is used as a way of suggesting something and not really committing to it in case the other person thinks it's stupid. The kids I teach will ask for something or suggest something and then always add on "Just jokes" or "Kiiiiding", but they really aren't. As people become more comfortable with themselves, the need for a qualifier like that is less necessary and it seems to fade away on its own. When people do that all the time, it is important for the people around them to show that it is okay to say how you think or feel without having to back away from it and people will be supportive rather than squashing them.
Bullshit... i smile when i am entertained or when i sense that i have the upper hand in a clash.
I enjoyed reading all the posts but this was my favorite, he said bullshit and then proceeded to prove my point LOL! ironically, (and I was really laughing) I was so entertained by that, I laughed and I experienced his point that we do laugh when entertained. But yes we have far more reasons for laughing, I guess you could say we laugh in many different ways.
I use "lol" as more of an expression. If something isn't too serious or if it's just generally light hearted, I'll respond sometimes with an "lol" to show that I'm interested and/or amused by what they are doing, that is assuming that I have nothing to say. I use "lmao" or "rofl" or "LOL" when something REALLY gets me and I start to actually laugh.
I think the original intend of laughter was to release tension and to show to others that they're safe with you, much like cats purr to show to their kittens that they're safe with the mother.
Laughter is, in fact, exhaling abruptly all the air you keep in your lungs, and then inhale a good quantity of fresh air. Sometimes it stops there, sometimes you repeat the process.
As for the making people feel safe part, I'm a bit confused about this, because once I read that dogs interpret smiling as baring your teeth, thus as aggressiveness. But I think the human perception is different. When you laugh, despite the fact your face muscles are tense, you appear less attentive to your environment, less observative and less in tune with the word around you. So you show to others that there's nothing to be afraid of and that they're in no danger when they are with you, cause you're not being very attentive at the moment.
Furthermore, we use to perceive as fake laughter the kind of smile that does not touch the eyes. This could be a sign that the person that is faking laughter is, in fact, still attentive to what's going on around them, so the no danger message they're trying to convey is just a distraction.
On a more on topic note, I laugh when something is funny and/or exciting.
I laugh out of sheer joy as I have not a shred of hesitance in communicating and I certainly do not have a lack of confidence.
My laughter is LOUD, it is boisterous, and can be heard far, far away.
Some friends of mine went out to a night club years ago, not knowing I was there. Then out of nowhere I started cracking up and shortly after, my friend Jeff walked up behind me, sjaking his head with a smile on his face, and said "Alex, your laugh is so loud and so distinct, there is no doubt who is coming from." I was kind of embarrassed actually, and said so, but my friend replied "No, don't take that the wrong way! It's like a beacon. It makes it very easy to find you even in a crowded place like this."
I truly am a happy and confident person, and I guess my laughter is reflective of that.