Being Human
Related Articles
Can humans feel wetness? The sensation of wetness is a fundamental aspect of our daily lives, yet it is a concept that we rarely stop to question.
We instinctively assume that when we come into contact with water or any other liquid, we can feel its wetness. However, recent scientific research is challenging this commonly held belief.
It suggests that humans might not perceive wetness directly but through a complex interplay of sensory information and cognitive processes.
If your curiosity has led you here, good for you! We’ll be looking at the science behind our perception of wetness to help us understand how our brain interprets the world around us. But before we go any further, let’s first answer the question,
Can Humans Feel Wetness?
According to research conducted by UK scientists, our skin does not have receptors that specifically sense wetness.
Instead, the sensation of wetness is more of a “perceptual illusion” created by our brain based on previous experiences with stimuli that we have learned are wet.
Other cues like temperature, touch, and tactile sensations, such as pressure, influence this wetness perception.
The Perception of Wetness: How Does It Work?
Our skin contains numerous nerve endings that react to various stimuli. These include receptors for touch, vibration, heat, cold, and pain.
Surprisingly, there are no specific receptors for wetness. It’s likely because water is a fundamental component of all living cells, and it would be impractical for nerve cells to fire in response to their composition constantly.
Take a moment and imagine how it would have been if our skin had receptors for wetness, yet water makes up 60% of our bodies.
Instead, our nervous system recognizes wetness through cold sensation, pressure, and texture.
A study conducted at Loughborough University in 2014 discovered that hairy skin is more sensitive to wetness than smooth skin. And this is because hairy skin possesses more temperature-sensitive nerve endings.
Interestingly, newborns do not have an innate sense of being wet or dry; they perceive sensations as cold or warm.
As we grow older and gain experiences, we start associating the feeling of cold fabric sticking to our skin with the presence of moisture from sitting on a damp park bench and so on.
Sensory Mechanisms And Skin Receptors
The sensory mechanisms and skin receptors are important in our ability to perceive and interact with the world.
Our skin has specialized receptors that detect sensory inputs such as touch, temperature, pain, itch, and pressure.
These receptors are distributed throughout the skin and serve as our body’s first defense against potential harm or danger.
Several types of skin receptors are responsible for different sensations. Meissner’s corpuscles, for instance, are located superficially within the dermal papillae and are responsible for detecting light touch and vibration.
On the other hand, Merkel cells are found on the top layer of the skin and are involved in the perception of touch. Another type of receptor, known as Pacinian corpuscles, responds to deep pressure and vibrations.
The process by which these receptors work involves the conversion of physical stimuli into electrical signals that the brain can interpret.
When a stimulus, such as pressure or temperature, is applied to the skin, it activates the corresponding receptor, which triggers a series of electrochemical events that generate nerve impulses.
These impulses then travel along sensory nerve fibres to the spinal cord and eventually reach the brain, where they are processed and interpreted as a specific sensation.
Thermo-receptors are responsible for detecting temperature changes, allowing us to perceive sensations of heat or cold. Nociceptors, on the other hand, are responsible for detecting pain.
They are particularly sensitive to potentially harmful stimuli such as extreme temperatures, intense pressure, or tissue damage.
Dry Damp And Wet Sensations
Let’s compare wetness to other related sensations, such as dryness and dampness, to better understand wetness. Dryness is often associated with the absence of moisture or the evaporation of liquid from a surface.
When your skin lacks moisture, it can feel dry and rough. On the other hand, dampness refers to a slight presence of moisture that has not yet reached the level of full wetness. Dampness can create a sensation of stickiness or clamminess on the skin.
Differentiating between these sensations is important because they can influence your perception of wetness.
For example, if you are accustomed to feeling dryness, even a slight increase in moisture may be interpreted as wetness. Similarly, if you are used to feeling dampness, your perception of wetness may require a higher moisture level.
The Role Of Temperature In Perception Of Wetness
The perception of wetness on the skin is influenced by many sensory cues, one of which is temperature.
Our skin has thermoreceptors, sensory receptors sensitive to temperature changes. These receptors are closely intertwined with our perception of wetness.
When a wet substance touches our skin, it often feels cooler than our body temperature due to the process of evaporation.
This cooling effect is particularly noticeable when the liquid is at a lower temperature than our skin. The thermoreceptors detect this temperature difference and send signals to our brains.
For instance, if you touch a room-temperature wet surface, the cooling effect might be subtle, and your perception of wetness might primarily arise from the tactile sensation of the liquid on your skin.
However, if you touch a cold or icy liquid, the temperature contrast becomes more pronounced, intensifying the feeling of wetness.
Conversely, when you touch a liquid warmer than your skin temperature, such as a warm shower, the initial sensation might be less focused on wetness and more on comforting warmth.
In such cases, the temperature of the liquid can influence how you perceive wetness – you can experience it as less intense due to the higher temperature providing a sense of comfort.
The Role Of Pressure In The Perception Of Wetness
When we touch a wet object or surface, our skin receptors detect both the presence of moisture and the pressure exerted by the liquid.
The receptors responsible are mechanoreceptors sensitive to various tactile sensations, including pressure.
The sensation of wetness results from our brain processing the signals from these mechanoreceptors in conjunction with other sensory inputs.
For instance, imagine placing your hand on a wet sponge. The liquid in the sponge comes into contact with your skin, causing slight deformation of the skin’s surface.
This deformation activates the mechanoreceptors, which then send signals to your brain. These signals, combined with other sensory information like temperature, create the perception of being wet.
Studies have shown that varying pressure levels can influence how we perceive wetness. When applied more intensely, pressure leads to a stronger perception of wetness and vice versa.
Why Does Your Skin Feel Wet, When It’s Not?
The sensation of wetness on the skin, even when not wet, can result from a combination of various physical stimuli.
Our skin has numerous sensory receptors that respond to stimuli like temperature, pressure, and texture.
When triggered in a specific way, they can create the illusion of moisture on the skin. This phenomenon is known as phantom wetness.
Phantom wetness is not a normal sensation and is often associated with a neurological disorder called dysesthesia.
Abnormal sensations or heightened sensitivity to stimuli characterizes dysesthesia. It can manifest in various forms, including the perception of wetness on the skin without any actual moisture present.
The exact cause of dysesthesia is not well understood, but there’s reason to believe it’s related to dysfunction in the nervous system.
Why Does Wetness Feel Different On Various Parts Of The Body, Such As The Hands Versus The Back?
The variation in wetness perception across different body parts differs because of the density of sensory receptors and the skin’s thickness.
Areas with more receptors, like hands, are highly sensitive to wetness due to a concentrated response to moisture.
Thicker skin, as on the back, might offer a less acute perception. Moreover, nerve distribution and receptor types influence how we feel wetness.
Conclusion
Can humans feel wetness? While our skin is equipped with receptors sensitive to temperature, pressure, and pain, no specific receptor is dedicated to detecting wetness.
However, by combining these sensory inputs, our brain can interpret the sensation of being wet. The texture, temperature, and previous experiences with wetness influence this interpretation.
