In some ways, science fiction can be seen as a prediction of what literature will be like in the future. The focus of the best science fiction remains on character and emotion, much as the heralded works of literature do so.
The difference, then, is that science fiction projects these characters and emotions into a future world. In this sense, the effect of modern science fiction on the modern reader can be thought of as being akin to that of a reader in the Middle Ages stumbling upon a copy of modern literary fiction--the situations and emotions would ring true for the reader, once he or she got past the strange and unimaginable technology.
An example of this is the work of William Gibson, best-selling author and progenitor of the "cyberpunk" genre of stylish, cyberspace-heavy science fiction (he is, in fact, credited with coining the term "cyberspace"). His early work is an exercise in imagination applied to the rising technology of computer networks, in which "cowboys" roam streams of data and break through code in a near-perfect prediction of the hackers which emerged as soon as there were systems to hack.
His most recent novel, Pattern Recognition, seems to be more of the same: dark, technological intrigue, high-tech computer hacking and clashing cultures--only the novel is set in present day and includes only present technology. While Pattern Recognition would have been indistinguishable from his other novels if it were read 10 years ago, it now shows how thin the line can be in literature between science fact and science fiction.