Nineteen subjects performed a choice reaction time task in which two levels of choice (two and four stimuli), and two levels of spatial attention (narrow and wide) were manipulated under each of two smoking conditions: sham smoking (denicotinised cigarette) or regular smoking (0.8 mg nicotine cigarette). All three factors significantly affected reaction time, with the smallest reaction times being recorded to the two-choice narrow grouped stimuli recorded under the high nicotine condition. Nicotine appears to speed decision time for both complex and hard-to-attend tasks, which is compatible with a role for nicotinic receptors in systems jointly mediating attention, memory and processing speed.

Two experiments investigating the effects of nicotine on performance in the inspection time (IT) procedure are reported. Experiment 1 compared ITs in smoking (0.8 mg nicotine cigarette), sham-smoking, and no-smoking conditions. IT was significantly shorter in the smoking condition as compared to both the no-smoking or sham-smoking conditions, suggesting that nicotine enhances early information processing. This result is of particular interest because of the correlation between IT and IQ reported in previous experiments. The nicotine related decrease in IT raises the possibility that nicotine enhances at least a subset of the physiological processes underlying intellectual performance. Experiment 2 examined the persistence of this nicotine related enhancement in IT, and investigated the effects of nicotine across 480 IT trials. Results suggested that ITs derived from the last third of the 480 trials were significantly shorter in the 0.8 mg cigarette condition than in no-smoking condition. The results from these two experiments, taken together with recent work examining the effects of nicotine on the string length measure of AEP waveform complexity and Hick decision time (DT), and studies investigating cognitive functioning and cholinergic system dysfunction in dementia, suggest a role of the cholinergic system in intellectual performance.

The effects of immediate post-learning smoking of low and medium nicotine delivery cigarettes were compared to those of smoking a denicotinised cigarette and a no-smoking control condition in a paired-associate learning task. Thirty-nine male smokers were tested for retention of the memorised material at 1 week post-learning. All subjects received all conditions in a repeated measures design. The low nicotine condition was associated with significantly fewer errors on first trial of recall and fewer total errors to criterion. There were no differences in performance reported between the no-smoking and zero nicotine conditions. The medium nicotine condition produced results part way between the no-smoking and low nicotine conditions. Results are discussed in terms of the effects of nicotine on long-term consolidation mechanisms.

The effects of smoking deprivation and of smoking a single .8 mg, 1.3 mg or 2 mg nicotine yield cigarette, immediately post acquisition on a paired-associate learning task, were studied in 54 male smokers and 15 male nonsmokers. Subjects were retested for retention of the memorized material at intervals of one-half hour, one day, one week, and one month. Nonsmokers showed superior recall to all smokers at one-half-hour retest, and to some of the smoking groups on later re-tests. At one-month retest the low- and middle-nicotine cigarette smokers outperformed high-nicotine cigarette smokers. Low/middle-nicotine smokers achieved superior recall to nonsmokers at one-month retest. Results are discussed in terms of smoker versus nonsmoker differences, in terms of the effects of nicotine on memory consolidation, and in terms of the PAL response measure adopted.

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