Olfaction is different than our other senses because connections between the sensory receptors and the brain are ipsilateral. Our olfactory nerve tracks do not cross over each other at the base of the brain as they do with, for instance, the optic chiasm, as shown in Activity 2.1. The reason this is interesting is because the cerebral hemispheres are known to be specialized to some degree for different functions (lateralization of function). For example, it has been well established that for almost all right-handed individuals, language is lateralized to the left hemisphere of the brain. In contrast, neurological evidence suggests that our experience and processing of emotions is lateralized to the right hemisphere.
Interestingly, olfaction also appears to be preferentially lateralized to the right hemisphere. The fact that both olfaction and emotion are processed in the right hemisphere while language is processed in the left has some important consequences. When you sniff an odor (e.g., coconut extract), you will evaluate it as more pleasant (more emotionally positive), if you sniff it through your right nostril than if you sniff it through your left nostril. However, you will be more likely to correctly name the odor as being “coconut” if you sniff it through your left nostril rather than your right. In other words, our emotional responses to odors are heightened by smelling with our right hemisphere where emotion is more dominant, and our verbal labeling abilities with odors are improved by smelling with the left hemisphere where language is more dominant.
You may put this information to practical benefit next time you are comparison shopping for fragrances products. In this situation you might want to restrict your sniffs to your right nostril, so that you can most fully assess how pleasurable the scents are to you. By contrast, if you are a student in wine tasting class being asked to name the various odor components of a Cabernet Sauvignon, you would be advised to focus your sniffs to your left nostril.