The human senses are our contact to the environment. The human brain combines the fireworks of neurons for seeing, hearing, smelling, tasting, and touching into a meaningful whole. But we usually don't think about our senses until an organ stops working.
Humans have five senses: the eyes to see, the tongue to taste, the nose to smell, the ears to hear, and the skin to touch. By far the most important organs of sense are our eyes. We perceive up to 80% of all impressions by means of our sight. And if other senses such as taste or smell stop working, it's the eyes that best protect us from danger.
Cold viruses hit on average three or four times a year. When people catch cold, they feel terribly tired and their senses of smell and taste deteriorate. As a result, it is suddenly no longer possible for us to smell rotten food. Smell is a genetically predetermined program. It used to be essential for survival, as the only possible way to distinguish what was edible from what was inedible was through smell. If the sense of smell stops working, the eyes need to take over, both in looking for mold and other traces of spoilage, as well as in reading the small print of the expiry date.
It may sound strange at first, but in addition to the sense of taste, the eyes also play a major role in deciding whether something tastes good or not. In contrast to the other senses, the sense of taste is very weak: while it is possible for us to distinguish between thousands of colors with our eyes, we have the ability to distinguish only five flavors: sweet, sour, salty, bitter and umami – which roughly translates as “meaty” – a natural flavor enhancer which is found especially in tomatoes, cheese, and meat. But as already mentioned, the sense of taste does not only rely on the tongue, but also on the eyes. For example, yellow, orange, and especially red food is considered sweeter than food of other colors. Even professional wine connoisseurs have been fooled in the past. When French researchers offered them white wine dyed with red food coloring, nine out of ten professionals could not distinguish it from ordinary red wine.
The sense of sight plays a decisive role in the magic of a first meeting. Gestures, facial expressions, and body language make up a large part of the overall impression. Within fractions of a second, people decide whether they find someone attractive or not. It is only in getting to know each other better that other senses – in particular the sense of smell – have a role.
Millions of people all over the world face problems with their hearing. Only very few of them make use of the currently existing technical possibilities in order to improve their situation. For these people, a conversation in a large group may become a word salad, and music just a blend of noises. There are also many dangers for these people as they can no longer hear the honk from a car, the wail of police sirens, or the whistle of a kettle. At this point, the eyes must take over – in traffic, and in the household.
Blind people also compensate for their disability with other senses. For example, with intensive training, they can use their sense of hearing to orient themselves in space or their sense of smell to recognize people and places.
People who were previously able to see, but lost their sight because of illness or an accident can remember colors for the rest of their lives. People who have been blind from birth have no proper idea of colors, but they still understand the meaning of light and dark, of bright and dull.