Effects of nicotine on pupil size and performance during multiple-object tracking in non-nicotine users.

Nicotine has been commonly used in pyschopharmacological studies, showing its benefits as a pharmacological stimulant on cognitive performance. In the current study, we investigated the effects of 2 mg (Experiment 1) and 4 mg (Experiment 2) of nicotine on performance on a multiple-object-tracking task. Participants were young non-smoking adults with no pre-existing attentional deficits. Nicotine and placebo were administered through nicotine and nicotine-free taste-matched chewing gum, respectively. Additionally, we compared pupil size between nicotine and placebo conditions in both experiments. Although we found that pupil size was considerably smaller in the nicotine conditions, nicotine administration did not appear to facilitate behavioural performance. We speculate that nicotine might enhance performance only for certain cognitive functions, and only for specific populations, such as nicotine-deprived smokers.