"Smells can even help us carry out tasks, according to an experiment by Martin's colleague Alison Gould. In one experiment, subjects completed a tedious "visual vigilance task" in the presence of either no odor, an alerting (peppermint) smell, or a relaxing (bergamot) one. They did better with the peppermint. Another study showed that subjects performed an unchallenging task better when stimulated by an unpleasant smell --in this case, sour milk. A pleasant smell, that of an air freshener, helped them perform complex tasks better."