Rationale: It is now well established from electrophysiological and behavio
ural evidence that nicotine has effects on information processing. The resu
lts are usually explained either by a primary effect of nicotine or by a re
versal effect of a nicotine-induced, abstinence deficit. In addition, there
is dispute about the cognitive processes underlying the changes in perform
ance. Methods: This study has approached the first question by using the ni
cotine patch, in order to administer nicotine chronically. In addition, we
examined the effects of nicotine on attention with a selection of tests whi
ch assessed the intensity and selectivity features of attention, using the
Random Letter Generation test, the Flexibility of Attention test and the St
roop test. Results: Nicotine enhanced the speed of number generation and th
e speed of processing in both the control and interference conditions of th
e Stroop test. There were no effects on attentional switching of the Flexib
ility of Attention lest. Conclusion: The results are consistent with the hy
pothesis that nicotine mainly improves the intensity feature of attention,
rather than the selectivity feature.