The process of human perception is a complex multisensory mechanism in which multiple sensory organs interact, shaping our sensations of taste, movement, and the surrounding world. This is reported by Barry Smith, a researcher at the University of London.
Neuroscientists increasingly perceive sensory perception as a distributed system where various sensory channels constantly interact, creating a unified awareness of the external world and our own bodies. A change in one of the input signals, whether it be sound, smell, or movement, can subtly alter our sensations.
Long periods spent in front of screens can lead us to ignore sensations beyond sight and hearing, even though they are always active. When we begin to pay attention, we can feel the contrast between rough and smooth surfaces, how tense our shoulders are, or how soft a piece of bread is in our hands.
Our everyday sensations are full of such quiet signals. In the morning, we feel a tingling from toothpaste, hear the rush of water in the shower, and smell shampoo, and later enjoy the aroma of freshly brewed coffee.
Although Aristotle identified five senses, he also believed that the world consists of five elements—a notion that modern science no longer supports. Scientific research shows that human perception is based on a greater number of senses than just five.
Our senses work in unison.
Most of our experiences are based on multisensory perception. Vision, hearing, smell, and touch do not act in isolation—they are interconnected and create a unified picture of our perception of the world and our own bodies.
What we feel influences our visual perceptions, and what we see can alter our auditory sensations. For example, different scents of shampoo can affect the perception of hair texture: the smell of rose can make hair feel silkier.
Smells in low-fat yogurts can create the impression of a richer and thicker taste, even without the addition of emulsifiers. The perception of smells rising from the mouth to the nose changes depending on the viscosity of the drinks.
Human senses are much more diverse than they seem.
Professor Charles Spence from the Crossmodal Laboratory at Oxford claims that neuroscientists believe there are between 22 and 33 different sensory organs.
These include proprioception, which allows us to be aware of the position of our limbs without visual control. The vestibular system, vision, and proprioception together provide our balance.
Interoception is another example, allowing us to feel changes in the body, such as a racing heartbeat or hunger. People who have had a stroke may not feel their limbs and may even think that someone else is controlling their movements.
This creates a sense of ownership: patients may feel that, for example, their hand does not belong to them, even if it retains sensations.
Taste and olfactory sensations are interconnected.
Some traditional sensory organs are a combination of several sensations. For example, touch includes pain, heat, itch, and tactile sensations. When we taste something, we are actually using a combination of touch, smell, and taste, creating flavor sensations from food and drinks.
Taste sensations arise from receptors on the tongue that allow us to distinguish salty, sweet, sour, bitter, and umami. But what about the flavors of fruits like raspberries or mango?
There are no receptors on the tongue for perceiving the taste of raspberries, and its flavor is not a simple combination of sweet, sour, and bitter. There is no arithmetic model for fruity flavors.
We perceive them through the synergy of the tongue and nose. Smell plays a key role in shaping what we consider to be taste.
However, it is not just about inhaling smells from the environment. Aromatic molecules are released during chewing or drinking and travel from the mouth to the nose through the pharynx.
Touch also matters, linking tastes and smells, determining our preferences, for example, regarding the texture of eggs or chocolate.
The vestibular system also affects vision. When you are on a plane and look down, you may notice that the front of the cabin seems higher when the plane is ascending, even though visually everything remains in place. This occurs due to the interaction of sight and sound, which informs you of your position.
Research shows how senses shape our behavior.
The senses are an important area for research, and philosophers, neuroscientists, and psychologists are working together at the Center for Sensory Studies at the University of London.
In 2013, the "Rethinking the Senses" project was launched under the late Professor Sir Colin Blakemore. We studied how changing the sound of one's own footsteps can affect the perception of body weight.
We also found that audio guides in the Tate Britain art museum, communicating with visitors as if speaking to a model in a portrait, help to better remember details of paintings. We discovered that the noise of airplanes affects our perception of taste and why tomato juice should be consumed on board.
While the perception of saltiness, sweetness, and acidity decreases in white noise conditions, the taste of umami remains unchanged, and tomatoes and tomato juice are rich in this flavor, highlighting their zestiness in a noisy airplane environment.
Everyday illusions reveal the complex nature of sensory perception.
At our interactive exhibition "Senses Unwrapped" in the King's Cross area of London, visitors can learn how their senses work and why they do not function as we expect.
For example, the illusion of size and weight can be demonstrated with a set of curling stones of different sizes, where the smallest stone seems the heaviest, even though they weigh the same on scales.
There are always many examples around that demonstrate the complexity of your sensory system if you take the time to be aware of them. So the next time you are walking or enjoying a meal, think about how your senses work together to create a shared perception.
Adapted from an article originally published in The Conversation
Note: Barry Smith received funding from the Arts and Humanities Research Council for his research on multisensory experience, which formed the basis for this exhibition dedicated to the senses.
