Effects of Essential Oils on Human Cognition

The use of essential oils to control arousal and cognitive performance has a long tradition in mankind. In our time, the demand for remedies promising fast but safe recovery from mental stress is ever growing. Thus, today a plethora of popular aromatherapy guidebooks exists, offering advice on the use of essential oils for a multitude of health complaints. With some delay, scientists have started to substantiate the claims raised in the popular literature and verify the effects of essential oils on cognitive functioning and performance. This chapter aims to give an overview about the available scientific literature dealing with the influence of essential oils and fragrances on arousal and cognitive performance. The topics covered in this chapter will range from brain potentials related to arousal over alertness and attention to learning and memory. In addition, it will be discussed whether olfactory versus non-olfactory administration influences the effects of essential oils on cognitive functions and how psychological phenomena, such as hedonic preferences, semantic associations, and individual expectations may shape these effects.