Smell senses Do humans have a true super-nose?

Human sense of smell significantly better than expected
So far, the human sense of smell compared to dogs and other animals was rather lagging behind. However, the journal "Science" has now published an interview with a renowned neuroscientist, according to which our sense of smell is much better than many believe. John McGann of Rutgers University, New Brunswick, New Jersey, explains in the interview how he felt that he could misjudge the human sense of smell.

Most people have heard before that their sense of smell can not be convincing compared to dogs and other animals. Scientifically, this consideration was originally based on the relatively small size of the so-called olfactory system in relation to the size of our brain as a whole. For example, this takes up relatively much more space in mice or dogs. But according to John McGann, humans can smell much better than previously thought.

The human sense of smell has long been considered particularly bad, but this is an incorrect prejudice. (Image: ruigsantos / fotolia.de)

Origins of misjudgment of the sense of smell
According to the expert, the assumption that our sense of smell is rather bad goes back to the 19th century, when French anatomist and anthropologist Paul Broca compared the brains of different animals to the human brain. The so-called olfactory bulb (olfactory bulb) of humans was very small in comparison to the size of the whole brain. In contrast, in a mouse or a rat, the olfactory bulb seemed much more pronounced in relation to total brain size, reports McGann.

Free will beats sense of smell
Also, Broca felt that an important part of free will is not affected by odors, which distinguishes us humans from animals, following animalistic instincts towards certain behaviors such as mating behavior, explains McGann. People are able to decide freely how they react to odors. An idea that, according to McGann, was also supported by the ideas of Sigmund Freud, who equated the smell with an animal thing that had to be left behind when we humans became rational beings.

People as a snooping track seeker
Over the centuries, psychology, philosophy and anthropology have led in various ways to the assumption that people do not have a good sense of smell, explains the expert. But recent studies come to a different conclusion, according to McGann. For example, a few years ago a study showed that we can distinguish one billion different odors. In another study from the University of California, scientists had set a scent trail on a field that was supposed to follow blindfolded people on all fours. The participating students were well able to follow the path laid out in the field, reports McGann.

Different strengths in odor discrimination
Although the study did not compare the sense of smell of humans and dogs and McGann suspects that the dogs - depending on the smell - would win. But it becomes clear that the limits of the search for traces by means of the human sense of smell have not been really investigated. "When you look at common odors that may even be very similar to each other, you will find that people are most sensitive to one and dogs are the most sensitive to one another," the expert continues.

Blood scent we took was particularly intense
According to McGann, the human sense of smell, for example, is particularly sensitive to a component of human blood odor. Smells are processed not only in the olfactory center but also in brain regions such as the amygdala and the hippocampus, explains the expert. For example, smells are associated with emotions and memories. In a recent study, scientists from the universities of Bern, Cologne and Bochum also found that fragrance hedione has an impact on human behavior and cooperation.

Sense of smell often neglected
According to the expert, the human sense of smell deserves much more attention. Many people lose their sense of smell and then feel the impairments, says McGann. "Losing your sense of smell affects your overall psychological well-being," says the neuroscientist. For example, associations with depression and impairments in social interaction have been proven in the case of a loss of the sense of smell. (Fp)