Nostril Dominance

People are either right-handed or left-handed. But are people also left-nostriled and right-nostriled? Yes, they are — as reported in an article published in the journal Laterality (Mar 2005). From the study:

we sought to determine which nostril has the greater airflow most of the time. In line with the notion of a biological preparedness for sidedness consistency, it was hypothesised that left-handers have their left nostril as the dominant one (defined as the nostril with the greater airflow) significantly more often than their right nostril. For right-handers the opposite was predicted: the right nostril would most often experience the greater airflow...

Result: The present data support these predictions: for both left-handers and right-handers the nostril that had the significantly greater airflow was ipsilateral to the preferred hand almost 60% of the time.

The researchers also discovered that people are pretty much useless at self-determining their own nostril dominance. (i.e. It's very hard to tell which nostril you're breathing more air through.) So they used a gadget that measured airflow into each nostril to get an accurate measure of nostril dominance.