Have any studies been done on the psychology of reading email?  What
makes a person read/skim/ignore an email they receive, which at some
level they know they should read, but they're too busy/don't care/will
read later/other mental excuses.  (I'm not a spammer, just trying to
get project team members to read my necessarily long, detailed emails
rather than repeatedly asking me for the same information later).  I'm
wondering if perhaps structuring the messages differently might help.

For example:
- single long email vs several short emails, perhaps sent spread over some time
- good ways of breaking up an email (i.e. ascii bullet points, or
headings, etc.), vs. one long section (with resulting slightly smaller
total length)
- short paragraphs (looks more manageable) vs long (and resulting smaller total)

I'm asking specifically about email correspondence, not writing in
general.  Finally, I'm looking for any actual studies/research done on
this (whether academic or amatuer), not just general advice about
editing->brevity->good.

Thanks.