I am talking in terms of values. Is there any difference between these two when it comes to the weight they add to a CV? Is a paper presentation better than a poster presentation?
I'm distant from your area... but, in math, in the U.S., a "poster presentation" is sort of a nice thing for undergrads or beginning grad students to do, but rarely is of any consequence.
Presentations, either of papers or free-standing, are much more substantive, to begin with... and are much higher status, CV-padding-wise, as well. You'll have an actual audience, to begin with!!!
This probably depends on the field, but in CS, at least, a paper presentation is much more valued than a poster. Moreover, conferences are thought of as more valuable than journal publications due to the sorter time scale between submission and the conference vs submission and final publication.
A paper presentation almost certainly gets more review than a poster, even with short time scales. Posters may be most valuable to students looking to get a start on making their, not quite ready, work visible and getting some feedback from conference attendees.
Moreover, it may be (or not) that the papers are published in the proceedings or an associated journal that doesn't include posters.
For some purposes one can do both, actually, even at the same conferences. The paper is expected to be more refined and complete, however.
You asked another question concerning literature. That field might be quite different. If you are a student then a professor in your field can probably give a tailored answer.
I think that a lot of the effect of poster and paper presentations, in terms of their later (general) reputational value, depends on two main things.
- The number of people of importance and influence who would come to your paper presentation versus a poster viewing.
- The way in which posters versus papers are reported in any subsequent summary of proceedings.
Some post-conference publications include author-edited versions of the papers that were presented; when that happens, the posters are often not mentioned at all. The consequence is that when you cite your paper, people can read what it was about; but when it comes to citing your poster, the best that you can rely on is a line in the pre-conference agenda!
However, if there is no post-conference publication of papers, then it seems to me that there is little potential difference between a paper and a poster. You are really relying a lot on the conference attendees themselves to be the diseminators of your ideas (see point 1).
The Computer Science field is very good at publishing conference papers. I have no idea about the English Literature area.
In terms of CV weighting, my experience in the area of experimental psychology is that posters and conference papers tend to be treated much the same ... low!