As an undergraduate student, I find it hard to understand research papers on any particular subject.
Why don't researchers use simple language for their reports, so that everyone would understand?
Update: I will leave this post as a general discussion on this topic. Feel free to edit question.
In short, because it is difficult to express something concisely, and precisely in language that any undergraduate can understand.
Conciseness is required not just because without it every report would be inconveniently long to write and to read, but because it would be harder to understand. It would be harder to understand because the jargon neatly encapsulates a bundle of concepts (e.g. its definition and related properties) into a single concept. And we can only be thinking about so many concepts at a time.
Consider the statement about the Stone–Weierstrass theorem:
A mathematician might say:
Polynomial functions are dense in C[a,b] ⊂ (ℝ→ℝ)
To expand out the math, so that one does not have to know the notations on gets:
Polynomial functions are dense in the space of continuous real-valued functions defined on a closed interval.
But still perhaps the word dense is beyond the understanding of an undergrad.
So let's expand it to not use that:
For every continuous real-valued function defined an interval; then for any positive real constant one might care to define, a polynomial can be found such that for every point on that interval the absolute difference between the value of that polynomial and the value of the real function at the point is smaller than the constant.
So that is how much most space it took and how many more ideas one has to keep track of for that fairly simple use of jargon. When thinking about such a problem rarely is the mathematician thinking about what is going on with the distance of points in a hypothetical polynomial. They are just thinking "it is dense".
Now imagine expanding all the terms in the generalized version of the above:
Stone–Weierstrass Theorem (real numbers). Suppose X is a compact Hausdorff space and A is a subalgebra of C(X, R) which contains a non-zero constant function. Then A is dense in C(X, R) if and only if it separates points.
(This last is a direct quote from the Wikipedia page on the Stone–Weierstrass theorem, the preceding quotes are not, though are to some extent paraphrases.)
Then to go the other point on preciseness, There is a really high chance someone is going to comment on this answer saying that actually my statement is not quite correct, that I've not fully captured the definitions in my explanation
While, yes, every paper could repeat some introductory information, then that would inconvenience any reader who is looking to find the core idea, since it would be drowned in a sea of background material.
And you might say that "this answer is hard to understand, in the expanded form, you did a poor job at making it understandable to an undergraduate.", and I'ld say "Fair enough; I'm not great at making things easily understandable."
And that statement holds for most other researchers too. Not what most are good at -- it is why there are specialists in scientific communication.
The intended audience of a research paper is not 'everyone'; it is other researchers in the same field.
As a comparison, consider things like car manuals, or legal documents. It would be possible to write these in more accessible language, but that would detract from the primary purpose of the document.
In short, because undergraduate students are not the target audience of research papers' authors.
There are different possible reasons for a paper being "hard to understand".
One of the reasons was already elaborated in the other answers. It basically boils down to the presuppositions and assumptions that are made in technical terms. The writers expect the readers to have some familiarity with the subject. Special jargon or notations are used simply because they allow a certain brevity and precision. When a term has a specific meaning, the meaning is assumed to be known, and in doubt, can be looked up elsewhere. The details of this problem may also depend on the subject: In a mathematical paper, the main hurdle may be understanding certain notations. In a social sciences paper, the main difficulty may be in understanding the precise meaning of certain terms.
But there is another reason. It was also mentioned in the comments, and discussed in other questions. The reason is that the text itself may simply be written in a form that is hard to understand.
Going one level deeper, the obvious next question is: Why is the text written in this form?
I think, broadly speaking, there are two possible answers to this:
Interestingly, English is the only language for which a dedicated Wikipedia version exists, namely the Simple English Wikipedia - although this is only indirectly related to academic writing, it shows that similar problems exist in other areas.
I think there is a false premise to this question. Namely, the idea that researchers could write the same paper using mostly different words just does not make any sense (to me)!
Using different words makes a different piece of writing.
This is not a phenomenon that is unique to reaearch papers. I don't read books by Faulkner* to my toddler, and I would never complain that Faulkner should have written his books so that they would make sense to a 2-year-old.
Research papers are still pieces of writing. I agonize over words and phrases all the time, and when I'm done writing, there are lots of phrases that illustrate ideas and explain concepts exactly as I want. Outside of changes required/requested for journal editorial purposes, I would be quite unhappy to change these words and phrases. And yes, as others have said, this is affected by who my audience is. But all writing has an intended audience. There is no such thing as a piece of writing intended literally for everybody.
So at least from a personal stand point: I don't use different words mostly because they would be different from the ones I wanted to use :)
*William Faulkner is an American author who has a reputation for some of his writing being difficult to understand/interpret (I would say).
Be more precise: are you talking about unnecessarily complex language, or are you confused/irritated by specific terminology?
Some scientists do tend to use overly complex language to differentiate themselves from others "of lesser intellect" as they think. That does happen and is often just a sign of bad style or even bad knowledge as it suggests a level of expertise that might just not be there.
If you have issues with all scientific papers you might need to improve on your language skills. In science you need to be very precise, and stick to certain terminology. And since science papers are intended to be read by other scientists in the same field of research, authors expect readers to be familiar with terminology in that field and will not explain fundamental things. That's up to you.
However, a good paper should at least be easy to follow even though a reader might stumble upon a few expressions he or she is not familiar with.
Researchers generally use complicated language because their research covers complex topics. Thus they use words that will be familiar and precise to people who understand the topics. And precisely because these words are familiar to other experts, there is no point trying to explain them in a paper because someone else (probably several someones) will have already explained them better somewhere else. Thus if you are reading a paper as a non-expert (that is, a non-expert in the topic at hand; this applies equally well to experts in other fields) and come across terminology that you don't understand, this is a useful pointer that you should first go and read about it elsewhere. The real danger for non-experts reading scientific papers is that they might read something without realising they didn't understand it.
I don't think anyone can answer this for sure, but here's a personal guess.
Researchers don't actively attempt to write in an arcane manner. Making one's research accessible is a good thing! However, a genuine concern when writing is that one might be making too many "obvious" statements. Nobody wants to be making obvious statements since it both makes the author look junior + makes the work done seem simple (c.f. imposter syndrome). This gets more drastic the more experienced a researcher is, since more statements appear obvious to them. Of course what's obvious to an experienced researcher is probably not obvious to undergraduates, who are the unfortunate casualties of this.
I also get the feeling that authors want to make it seem like they have processed what was previously written (or simply want to avoid plagiarism), so when they write a paper using an equation in a previous paper, they commonly write the same equation in slightly different notation, e.g. by using different but equivalent expressions for the same factor. Again, experienced researchers have no trouble but undergraduates are unfortunate casualties.
Here are a couple more articles about this: an article in The Atlantic and another in Nature. Googling for "why are academic papers so hard to read" finds a lot more results.
If you find this ridiculous, then when you write papers in the future, try to make it accessible to a wide audience!
There is another pair of reasons that many articles are not easily understood but undergrads.
I once heard a prominent scholar joke "The language of Physics is broken English". This funny thought stems from the fact that while most articles are published in English, the scholars who write them generally know English as second language.
As a native English speaker, and a graduate student, I have found it difficult to write a paper. Why? Because I had to learn the language as it is used in my field of research. For most papers[1], the primary audience is for other scholars within the same field. Thus the language of the research field becomes a sort of dialect that others must conform too.
A good sentence in an article should have one, and only one, interpretation. If a sentence has more than one meaning, it does not properly convey the ideas to the reader. This is critical for a big reason. Each sentence makes a claim, and each claim should be provable by research.
Making sentences with only one meaning is sorta hard; it tends to make them technical, long, and ugly.
In contrast, fiction and journalism tend to give you room to imaging things as you want. Much easier to create beautiful flowing sentences if they can be ambiguous.
So from what I've seen, most first drafts are written by a grad student who don't write very well (me). It then gets emailed around, and everyone makes changes here and there, and the text of the document becomes incoherent. Then the grad student edits it some more, and is told to submit it. Imagine eating a dinner cooked in this manner!
[1] The exceptions are review papers, which are longer and use much more general language. Easier to read, too
In addition to the comment of Jessica B, there are even some "method" articles which don't even have a general introduction and directly report technical knowledge. The target audience of paper is crucial. However, after reading 10-20 papers you will start to see general outline so you will not find that difficult.
It is difficult to write scientific papers so that everyone can understand. The reasons have been nicely covered in other answers.
I want to point out that the authors would normally include their emails or addresses in their papers so that anyone can write to them and ask questions about their reports.
If you need to do research and read papers from other fields, you can always contact the authors about their papers. If you indicate your purpose and background, they can usually help. Just don't expect them to teach you the whole subject. I would say using the same etiquette for asking questions on stackexchange.
A lot of research papers are arguably written in a deliberately convoluted style to enhance the prestige of the authors: see https://www.plainenglish.co.uk/news/1212-unreadable-academic-writing.html
I rather like this quote: “In academia, it seems that when we have nothing much to say we attempt to distract attention from that sad fact by saying it as pretentiously and at as much length as possible.”
My research supervisor, Maurice Wilkes, had a disarming way of writing that made complex ideas seem very simple, and I have always tried to follow his example. The danger if you do that is that people might not appreciate the value of what you are saying, and many academics don't want to take this risk.
In reviewing papers for conferences I have generally found that when you take time to cut through the jargon, the ideas in difficult-to-read papers are no more profound or precise than the ideas expressed in papers that are much easier to read.
Research papers are not generally intended to teach; rather, they are designed to inform. However, that does not mean that an undergraduate cannot use them as a resource. Take the following example sentence from a research paper:
"Theory predicts, and some evidence demonstrates that in lakes, the depth of the thermocline can have a large structural influence on the spatial distribution, and strongly influences the composition of plankton communities."
This one sentence could take an entire chapter of an undergraduate limnology textbook to fully explain. However, there are dictionaries, encyclopedias, and, oh yeah, this thing called Google, that can make short work of gleaning its meaning. Terms like "thermocline" and "spatial distribution" and "plankton communities" can all be Googled and within a few minutes the meaning of the sentence will become clear, even to the most uninitiated.
In summary, if one simply accepts that most high-level research papers simply do not stand alone but in general contain terminology that requires additional research to properly understand, they can become very valuable sources of information.
Quite a lot of answers here being quite defensive of writing in papers. While it is true that jargon is not necessarily bad, that papers aren't aimed at undergraduates and some concepts are just difficult to get across, many papers are more difficult to read than is necessary.
There are several things in the culture of science writing that tend to lead to complex sentence structures and difficult to read prose. This becomes worst when students read academic texts and immitate the style in their own writing because they believe that is the way we must write.
The use of the passive voice. This is where the author removes themselves from the text: "The liquid was added to the flask" rather than "We/I added the liquid to the flask". There is no reason for this other than tradition. In my view it almost always makes things harder to read and should be stamped out.
Space requirements in journals. Some journals even have character limits. This leads authors to try and find "clever" ways to try and word things in as few characters as possible.
Use of unneccesarily formal sounding words "utilized" rather than "used" for example.
In addition to the good answers above: One additional reason is that the intersection of extraordinary science, literary talent and the will to exercise both is extremely small; the number is probably in the single digits. They all are famous. Russell, Feynman, Hawking, Dawkins come to mind. More?
