The effects of smoking on performance on the Garner speeded classification task

The Stroop task has been used by several investigators to examine the effects of nicotine and smoking on human selective attention, but this research has produced inconclusive results. In this article a new task is described, the Garner speeded classification task, that can be used to explore the influences of nicotine on human selective attention in a more detailed fashion than has been reported previously. In a study using this task reported here, 52 smokers performed the Garner task twice. Half the subjects smoked a cigarette between the first and second completion of the task, and the remainder did not smoke. The main findings were that smoking reduced the size of Garner interference for both reaction time and error measures, and that smoking reduced the size of Stroop interference for the error measure but not the reaction time measure. The degree of nicotine deprivation of the subjects at testing did not substantially affect this result. Moreover, there was a suggestion that the effect of smoking on Stroop interference was secondary to the effect on Garner interference, indicating that smoking, and thus presumably nicotine, principally attenuates the disruptive influence of task-irrelevant, but varying, dimensions in selection. (C) 1998 John Wiley & Sons, Ltd.