Have you ever wondered why you can’t smell your own scent, even though others can? Have you noticed that when you enter someone else’s home, there is always a specific smell? Has it ever occurred to you that your own home also has its own scent that you simply can’t detect? This phenomenon is called sensory adaptation, and today we will take a closer look at it.
Sensory adaptation – the key to understanding smell
Sensory adaptation is a surprisingly common phenomenon that we experience every day, often without even realizing it. It works by desensitizing stimuli that are constantly present in our environment, such as the smell of our home, the pressure of clothes on our skin, or the temperature of the water we are immersed in.
To understand why this happens, we need to consider what it means to perceive the world around us and how we do it. Our brain sits in a quiet, dark, soft interior, trying to make sense of everything happening outside. How do we form an image of the external universe? How does all of it get to our brain? The answer is through our senses.
How do our senses work?
Our body is covered with specialized neurons, each responding to specific types of signals. When sensory information is detected by one of these sensory receptors, we experience a sensation. For example, light entering our eye causes chemical changes in the cells of the retina. These chemical changes trigger a chain reaction of messages in the form of nerve impulses that reach the central nervous system. These are our senses.
The smell that never goes away, it just becomes invisible
If we assume that our homes have a scent, why don’t we smell it? It is related to how our nervous and sensory systems interpret and process information. Just as our eyes constantly adapt to the level of lighting, our sense of smell adapts to the smells that are constantly present. After a while of continuously perceiving a smell, our nervous system stops interpreting it as new information. The smell doesn’t disappear, but we stop consciously perceiving it. This is the action of sensory adaptation.
Other senses that can deceive you
Our ability to control sensory adaptation is largely limited because it is a natural and automatic process of the brain. Sensory adaptation aims to optimize our senses, allowing them to focus on new and important stimuli rather than those that are constantly present and irrelevant. However, certain aspects of sensory adaptation can be controlled. For example, there are training techniques related to sensory adaptation that can help utilize this phenomenon to improve sensory functions. Scientists are also investigating how various factors, such as attentional focus, can influence the process of sensory adaptation.
Another example is that people working in the perfume industry can learn to ignore certain common scents (such as the smell of coffee) to focus on the subtleties of new scents. Such individuals often use different techniques, such as regularly breathing fresh air, to “reset” their sense of smell and prevent excessive adaptation. This shows that although we cannot completely stop the process of sensory adaptation, we have certain tools and strategies that can help us manage this process.
The sense of smell is not the only one that undergoes sensory adaptation. Our sense of touch is another example that experiences the same phenomenon. For example, when we put on clothes, we initially feel their weight. But after a while, when our brain starts treating this weight as constant, we stop feeling it. The same thing happens when we put on a watch or wear glasses. After a while, we forget they are on us until something reminds us of their presence. When we are in a loud environment, such as a concert or a noisy café, our hearing can gradually adapt to the loudness, making the noise less intense.
Learn more:
- Stevenson, Richard J. “Psychological correlates of habitual odor perception.” Chemical Senses 40.6 (2015): 437-447.
- Wysocki, Charles J., et al. “Individual differences in sensitivity to the odor of 4, 16-androstadien-3-one.” Chemical Senses 31.8 (2006): 705-713.
- Zhou, Wen, et al. “Olfaction shapes host-parasite interactions in parasitic nematodes.” Proceedings of the National Academy of Sciences 108.35 (2011): 14589-14594.
- Webster, Ben, et al. “Olfactory perceptual learning is the best predictor of olfactory cognitive ability.” Chemical Senses 45.8 (2020): 687-694.
- Veldhuizen, Maria G., et al. “Identification of human gustatory cortex by activation likelihood estimation.” Human brain mapping 30.12 (2009): 3976-3986.
