RATIONALE:

Several studies provide evidence that nicotine alleviates the detrimental effects of distracting sensory stimuli. It is been suggested that nicotine may either act as a stimulus filter that prevents irrelevant stimuli entering awareness or by enhancing the attentional focus to relevant stimuli via a boost in processing capacity.

OBJECTIVES:

To differentiate between these two accounts, we administered nicotine to healthy non-smokers and investigated distractor interference in a visual search task with low and high perceptual load to tax processing capacity.

METHODS:

Thirty healthy non-smokers received either 7 mg transdermal nicotine or a matched placebo in a double blind within subject design 1 h prior to performing the visual search task with different fixation distractors.

RESULTS:

Nicotine reduced interference of incongruent distractors, but only under low-load conditions, where distractor effects were large. No effects of nicotine were observed under high-load conditions. Highly distractible subjects showed the largest effects of nicotine.

CONCLUSIONS:

The findings suggest that nicotine acts primarily as a stimulus filter that prevents irrelevant stimuli from entering awareness in situations of high distractor interference.