Smoking, processing speed and attention in a choice reaction time task.

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.