Being good at understanding how others feel has usually been associated with lending a friendly ear. But research from an American neuropsychologist suggests lending a friendly nostril could be far more helpful, writes Caroline Davis.
Marcello Spinella, from Richard Stockton College of New Jersey, has for the first time demonstrated the relationship between empathy and smell.
"The relationship between smell and empathy makes sense when you consider brain anatomy and people with brain injuries. Another study has shown that psychopaths have a poorer sense of smell than others," Dr Spinella said.
He took 28 healthy subjects and asked them to close their eyes and identify different scents, such as lemon, liquorice and cinnamon, using one nostril at a time. They then filled out an empathy questionnaire, rating themselves on items such as "it makes me sad to see a lonely stranger in the group".
High scores in the scent test usually accompanied high scores in the empathy test. Specifically, he found that right nostril smell identification correlated with empathy while the left nostril did not.
"At face value, one would not anticipate the relationship between smell and empathy: they're two totally different mental functions," Dr Spinella said. But he explained that smell and emotional functions are controlled by similar systems in the brain and that anatomical and brain imaging studies have shown three areas in which the functions appear to overlap.
Dr Spinella said he expected left-sided smell to be less associated with empathy since, unlike most of the senses, olfactory nerves connect directly to the same side of the brain. This means smelling through the right nostril is processed by the right hemisphere, believed to be predominant in emotions.
Understanding the relationship between sense and feeling could, Dr Spinella argued, help understand the basis for our emotions and personality. In particular, it could offer valuable insight into the mind of psychopaths.
The research appeared in the International Journal of Neuroscience .