Studies examining facilitation of human memory by the administration of nicotine have given equivocal results and it has been argued that the positive findings on memory may have resulted indirectly from an effect on attention, rather than from a direct effect on memory storage. This study compared the "attentional" and the "mnemonic" hypotheses directly, by using both immediate and delayed recall tasks in a verbal free recall study, in which volunteers smoked on a fixed regime during presentation of a 32 word list (namely, one puff after each of eight 4-word blocks). The serial position curve for immediate recall demonstrated a significant improvement on the later blocks of the list (an attentional effect) when volunteers smoked a nicotine-containing cigarette. However, improved performance was found for items at the beginning of the list on the delayed recall measure and this improvement was significant on the first block of 4 words. Since nicotine input had been taken after presentation of this information, the results demonstrate post-learning facilitation of memory by nicotine.