Hi kilobug, skepticism makes for the best investigation and good discussion.
In this case, any old error doesn't cause laughter, but it has to be one that violates your assumptions of what you or someone else is capable of. The example is of course anecdotal so I don't have a ton of information, but I would suggest that most of us, especially people trained in computers, don't expect the a person, or don't find it acceptable, for them to not be able to plug in a cord, or not to check, so that would definitely be the type of thing that would illicit laughter from us...though the more it happens, we likely would laugh less and less and start to just become annoyed. It can also be a matter of "I know you screwed up in some absurd way, but I'll be surprised by finding out what exactly you did this time."
Something would have to violate what you were taking for granted or already assuming to find it funny. This is similar to the "Accounting Errors" example from page 13 of the second paper. For an example, you may not have expected the cake to be totally perfect, to where some missed seasoning or so on wouldn't be outside of your assumptions. But you probably did, in fact, expect the person to know the basics of what would taste good. Let's say that you bit into the cake, it tasted bizarre, then you found out that the person had tried to bake it with pickles. THAT'S the kind of error that would violate your expectations and cause you to laugh. Especially if they were right there and they genuinely looked like they thought it was a good idea.
This is probably a great example of "first person" laughter, where we're actually laughing at our own expectations being sharply wrong. Like how we might laugh if we're looking for our hat and find out it was on our head. The quality-gap in this case is in YOUR ability to estimate what was going on...laughing at yourself and not the person who exceeded expectations, since you didn't expect that your friend could or would do that. As you can see the difference between first-person (at the self), second-person (such as at someone telling you a bad joke), and a known or unknown third person (the usual targets of jokes and humor) create a lot of the confusion.
Anxiety makes us less likely to laugh, but a good enough joke can overcome some anxiety, and the pleasure we feel from laughing certainly can make us feel better. Another cool thing about it is that laughter triggers from recognition in the brain of the person laughing, so a good joke can be stronger than simply telling someone that their problem is no big deal. I have a lot of this under the explanation for the saying "laughter is the best medicine" on page 18 of paper 2.
Humor certainly expresses itself in many complicated ways, but I think the underlying mechanism is pretty simple. It's similar to how evolution expresses itself in thousands of ways in how it creates life and programs our instincts, but the underlying mechanism of variation and selection is fairly easy to understand and can be explained in a short form.
I hope some of these explanations for the examples help to demonstrate that. Regardless, friendly skepticism and disagreement is invaluable.
Alrighty, with the mass downvoters gone, I can make the leap to posting some ideas. Here's the Humor Theory I've been developing over the last few months and have discussed at Meet-Ups, and have written two SSRN papers about, in one page. I've taken the document I posted on the Facebook group and retyped and formatted it here.
I strongly suspect that it's the correct solution to this unsolved problem. There was even a new neurology study released in the last few days that confirms one of the predictions I drew from this theory about the evolution of human intelligence.
Note that I tried to fit as much info as I could on the page, but obviously it's not enough space to cover everything, and the other papers are devoted to that. Any constructive questions, discussion etc are welcome.
A "Holy Grail" Humor Theory in One Page.
Plato, Aristotle, Kant, Freud, and hundreds of other philosophers have tried to understand humor. No one has ever found a single idea that explains it in all its forms, or shows what's sufficient to create it. Thus, it's been called a "Holy Grail" of social science. Consider this...
In small groups without language, where we evolved, social orders were needed for efficiency. But fighting for leadership would hurt them. So a peaceful, nonverbal method was extremely beneficial. Thus, the "gasp" we make when seeing someone fall evolved into a rapid-fire version at seeing certain failures, which allowed us to signal others to see what happened, and know who not to follow. The reaction, naturally, would feel good and make us smile, to lower our aggression and show no threat. This reaction is called laughter. The instinct that controls it is called humor. It's triggered by the brain weighing things it observes in the proportion:
Humor = ((Qualityexpected - Qualitydisplayed) * Noticeability * Validity) / Anxiety
Or H=((Qe-Qd)NV)/A. When the results of this ratio are greater than 0, we find the thing funny and will laugh, in the smallest amounts with slight smiles, small feelings of pleasure or small diaphragm spasms. The numerator terms simply state that something has to be significantly lower in quality than what we assumed, and we must notice it and feel it's real, and the denominator states that anxiety lowers the reaction. This is because laughter is a noisy reflex that threatens someone else's status, so if there is a chance of violence from the person, a danger to threatening a loved one's status, or a predator or other threat from making noise, the reflex will be mitigated. The common feeling amongst those situations, anxiety, has come to cause this.
This may appear to be an ad hoc hypothesis, but unlike those, this can clearly unite and explain everything we've observed about humor, including our cultural sayings and the scientific observations of the previous incomplete theories. Some noticed that it involves surprise, some noticed that it involves things being incorrect, all noticed the pleasure without seeing the reason. This covers all of it, naturally, and with a core concept simple enough to explain to a child. Our sayings, like "it's too soon" for a joke after a tragedy, can all be covered as well ("too soon" indicates that we still have anxiety associated with the event).
The previous confusion about humor came from a few things. For one, there are at least 4 types of laughter: At ourselves, at others we know, at others we don't know (who have an average expectation), and directly at the person with whom we're speaking. We often laugh for one reason instead of the other, like "bad jokes" making us laugh at the teller. In addition, besides physical failure, like slipping, we also have a basic laugh instinct for mental failure, through misplacement. We sense attempts to order things that have gone wrong. Puns and similar references trigger this. Furthermore, we laugh loudest when we notice multiple errors (quality-gaps) at once, like a person dressed foolishly (such as a court jester), exposing errors by others.
We call this the "Status Loss Theory," and we've written two papers on it. The first is 6 pages, offers a chart of old theories and explains this more, with 7 examples. The second is 27 pages and goes through 40 more examples, applying this concept to sayings, comedians, shows, memes, and other comedy types, and even drawing predictions from the theory that have been verified by very recent neurology studies, to hopefully exhaustively demonstrate the idea's explanatory power. If it's not complete, it should still make enough progress to greatly advance humor study. If it is, it should redefine the field. Thanks for your time.