^caffeine has been found to enhance both working memory and
  short-term storage memory. A study published in the August 2007
  issue of "Neurology" showed that elderly women who drank three
  cups of coffee or more a day had less decline in both working
  and storage memory compared to controls. A more recent, study
  published in the July 2009 issue of "Journal of Alzheimer's
  Disease," showed that caffeine can reverse the symptoms of
  Alzheimer's disease in aging mice. The researchers found that
  when the mice were given caffeine that corresponded to about
  five cups of coffee a day, the initial signs of cognitive
  impairment were reversed.

  Read more:
  http://www.livestrong.com/article/383334-the-effects-of-caffeine-on-short-term-memory/#ixzz2TbdfvVQW^