Can you contain a smell

Smell

The nose makes the first impression

The sense of smell is the most immediate of the human senses. When seeing, hearing or feeling, the signals first have to be processed in the cerebral cortex of the brain. Scents, on the other hand, have a direct effect on the limbic system in the brain, where emotions are processed and urges are directed.

When you walk into a room for the first time or meet a stranger, it is usually your sense of smell that gives you the first impression.

In addition, human memory is closely linked to smells and smells. A smell can suddenly transport you back to a long-ago and long-forgotten situation in which you first noticed it.

This "Proust effect" is named after the French author Marcel Proust. In his main work "In search of lost time" he describes a man who dips a piece of pastry into his tea, whereupon he has a wealth of memories of his childhood that were buried deep in his subconscious.

You can train yourself to smell

Every living being and many objects and materials give off scent in the form of molecules. When inhaled, the molecules reach the olfactory mucosa at the top of the nasal cavity.

This five square centimeter organ contains between ten and 30 million nerve cells that renew themselves every four to six weeks and have receptors for around 400 different fragrances.

The nerve cells flow into the olfactory bulb, the transition to the brain. From there, the information is passed on to different areas of the brain, combined and processed. Odors are usually very complex and often consist of several hundred elements.

When it comes to smelling, two nerves come into play. The olfactory nerve controls the actual smelling, while the pain-sensitive trigeminal nerve reacts to acrid smells such as chlorine, ammonia, smoke or even onions. The sense of smell is closely linked to the sense of taste, and only this link provides a differentiated taste experience.

A healthy person can distinguish more than 10,000 different scents. Those who specifically expose themselves to scents and try to categorize them increase their perception and can process and name the odor information better.

Choice of partner: You have to be able to "smell yourself"

The sense of smell is located in the biologically oldest part of the brain. It had an important function, especially in the early days of mankind. It warns of dangers from fire or gases, helps in the search for water and food and is crucial in distinguishing between edible and inedible foods before they are consumed.

Even the sweat of fear of other people can be broken - a decisive advantage in combat or in the event of impending danger.

The choice of partner also depends on the smell - which we are not even aware of in most cases. If "the chemistry is right" between two people, one can literally relate that to the smell of the two. Because the odor molecules that a person secretes contain information about the nature of their genetic make-up.

Research on mice and other mammals shows that these animals prefer partners whose genetic makeup is as different as possible from their own. This ensures that possible offspring are equipped with particularly good genes, for example by making the immune system particularly resistant.

In humans, too, researchers have found that close relatives often "cannot smell each other" in adulthood. It is concluded that this is to avoid incest, which usually leads to genetic defects in children.

Dislikes that one develops over time also influence the sense of smell: there are women who report that they cannot stand the body odor and even the aftershave of their ex-husband or harassing bosses.

Babies rely on their noses

Even in newborns, the sense of smell is fully developed. For example, it helps them to find the mother's breast immediately after the birth. The olfactory memory is mainly formed in the first three years of life. During this time you collect the majority of your olfactory impressions, all of which leave a trace in the brain.

Expectant mothers are extremely sensitive to smells, especially in the first trimester of pregnancy. The sense of smell becomes much more sensitive; many have aversions to food, perfume or smoke, which sometimes lead to nausea and vomiting.

Biologists explain this mechanism as protecting the child from potentially harmful influences from food or the environment. The embryo is very sensitive, especially in the first three months, as vital organs are formed during this time.

When the sense of smell is damaged

The older you get, the weaker your sense of smell becomes. From the age of 40, the ability to recognize and differentiate scents decreases. Smoking and frequent contact with chemicals and dirt or dust also reduce the ability to smell.

People who have lost their sense of smell suffer from what is known as anosmia. The reasons for this can be destroyed olfactory nerves, chronic inflammation, allergies, but also brain tumors or Alzheimer's diseases.

The sense of smell is considered relatively unimportant by many people, but the loss can have serious consequences.

Many sufferers suffer from psychological problems because they are no longer sure whether their own odor is too strong and possibly bothers others. Excessive washing compulsion and withdrawal from social life can be the result.

(First published: 2011. Last update: 16.09.2019)