Human smell has often been characterized as being deficient when compared to the smell abilities of some lower organisms. Summarized below are four myths about human smell that have been contradicted by research.
Myth 1: Human smell is less sensitive than that of other animals.
Research indicates that the individual smell receptor cells in humans will respond to a single odorant molecule. The difference in overall sensitivity appears to be due to the fact that some lower organisms, such as dogs, have more smell receptors.
Myth 2: Humans have a relatively poor ability to detect changes in smell intensity.
Although earlier research indicated that the difference threshold for smell was the largest of all the senses, more recent research, carefully controlling the concentrations of the smell stimuli, indicated that difference thresholds were equal to or lower in size than those for other senses.
Myth 3: Odor identification ability is poor in humans.
Although early research indicated that the ability to recognize previously presented odors was poor, this result may be related to the fact that unfamiliar odors were used as the stimuli. Odor identification accuracy is primarily a function of labeling, not smell. That is, if subjects are given the correct label of an odor when they are first exposed to it, their ability to later identify the odor is significantly improved.
Myth 4: Although many animals use odors to communicate, humans do not.
Several studies have demonstrated that individuals are able to identify correctly about 75 percent of the time whether odors associated with sweat or breath came from a male or female. Menstrual synchrony, a phenomenon in which women who live in close proximity for a period of time begin to have similar starting times for menstruation, has also been found to be related to smell.
