Olfactory Stimulation Eliminates Sex Differences on the Iowa Gambling Task

Abstract

The Iowa Gambling Task (IGT) is a widely used measure of decision making on which men typically perform better than women. During IGT performance men have increased activation in lateral orbital prefrontal cortex and right dorsolateral prefrontal cortex, whereas women have increased activation in left medial orbital prefrontal cortex. Because medial orbitofrontal cortex receives input from olfactory cortex, this study investigated the effect of olfactory stimulation on IGT performance. Subjects smelled an aroma through either the left or right nostril before every 10 trials of the IGT. There was no significant difference in task performance, measured by the number of advantageous cards selected, between men and women while smelling aromas. The performance of men was decreased to that of women under normal conditions. In other words, sex differences were eliminated by having men smell aromas during the task. There was no change in women’s performance when aromas were smelled.