Bilateral detection thresholds in dextrals and sinistrals reflect the more sensitive side of the nose, which is not lateralized [published erratum appears in Chem Senses 1998 Dec;23(6):761]

Several fundamental questions remain enigmatic concerning human olfactorysensitivity, including (i) whether detection threshold differences existbetween the two sides of the nose (and, if so, whether such differences areinfluenced by handedness) and (ii) whether bilateral (i.e. binasal)stimulation leads to lower thresholds than unilateral stimulation (and, ifso, whether the degree of facilitation is inversely related to generalolfactory ability). In this study, and well-validated single staircaseprocedure was used to establish bilateral and unilateral detectionthresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130right- and 33 left-handed subjects. No differences in sensitivity betweenthe left and right sides of the nose were observed in either group.Bilateral thresholds were lower, on average, than unilateral thresholdswhen the latter were categorized in terms of left and right nares. However,the bilateral thresholds did not differ significantly from those of theside of the nose with the lower threshold. Overall smell ability, asmeasured by the University of Pennsylvania Smell Identification Test, didnot interact with any of the test measures. These data imply that (i) theleft and right sides of the nose do not systematically differ in detectionthreshold sensitivity for either dextrals or sinistrals and (ii) if centralintegration of left:right olfactory threshold sensitivity occurs, itseffects do not exceed the function of the better side of the nose.