Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)




Caffeine is a central nervous system stimulant which is considered part of the normal diet. One approach to understanding whether ingestion of caffeine influences human cognition is to examine the effects of caffeine on memory.

This study examined the effects of caffeine ingested both before and after a prose learning task. Two hundred-forty-five subjects (121 males, 124 females) were divided into two groups. One group received 0, 2, or 4 mg/kg of caffeine before hearing three narrative prose passages. The second group received 0, 2, or 4 mg/kg of caffeine after hearing the prose passages. All subjects returned 24 hours later and wrote their recalls. Caffeine, ingested either before or after the presentation of prose passages, enhanced recall of these passages in females. In males, ingestion of caffeine after presentation of prose passages was detrimental to recall. The present results provided no clear evidence as to the reason for the observed gender differences. Speculation as to possible explanations for gender differences is included in the discussion.