Nicotine taken by ad lib smoking or other routes of administration has been
reported to shorten reaction time (RT) in many cognitive tasks. Most of th
ese tasks have used visually presented stimuli and require a simple motor r
esponse such as a button press. The reliance on this type of RT task makes
it difficult to determine the specific stage(s) affected by smoking/nicotin
e. Event-related potential studies indicate that visual perceptual processi
ng is faster after smoking/nicotine. However, recent studies indicated that
the magnitude of this enhancement is not sufficient to explain the total i
mprovement in RT performance due to smoking/nicotine. These studies suggest
that a significant performance-enhancement effect may occur after the deci
sion or classification of stimuli is completed. The next logical step in th
e information processing chain is response selection. We examined the effec
t of smoking/nicotine on response selection in a stimulus-response compatib
ility task. In this double-blind study, easy response-selection RTs were fa
cilitated by smoking/nicotine but difficult response-selection RTs were not
. Copyright (C) 1999 John Wiley & Sons, Ltd.