Sensory adaptation is a phenomenon that occurs when the sensory receptors become exposed to stimuli for a prolonged period. Depending on the stimulus, receptors may increase or decrease their ability to respond, and will develop an enhanced or diminished sensitivity to the stimulus. This can occur with all of our basic five senses: sight, hearing, smell, touch and taste.
TL;DR (Too Long; Didn't Read)
Sensory adaptation happens when the body’s sensory receptors are exposed to particular stimuli such as loud noise, high temperatures or strong scents for long enough that the receptors decrease their sensitivity to the stimuli, make them less noticeable. This happens when a tobacco smoker stops noticing the smell on their clothes and hair, or when a hot bath feels cool after being in the water for several minutes. Sensory adaptation also happens when certain stimuli are decreased and the receptors increase their sensitivity, such as when someone walks into a dark building and their pupils dilate to take in as much light as possible.
Our body’s visual system is able to adjust automatically to the intensity level of light in the environment. This adaptation happens when you enter a dark building after exposure to the sunlight. Your pupils dilate in order for the retina to gain access to additional light. The cones of your eyes increase in sensitivity as a reaction to the darkness; however, they adapt within approximately five minutes. The rods in your eyes have chemicals that increase with limited light and assist in the adaptation as well.
Individuals adapt to the noise within their environment. For those who live in an area with continuous traffic, their ears adapt to the constant sound until they no longer hear the noise of the traffic. With louder sounds, such as a rock band playing while entering a nightclub, the muscle attached to the inner ear bone contracts, reducing the sound vibration transmission. This decreases the vibrations to the inner ear, thereby adjusting to the noise level.
Those who smoke tobacco do not notice the smell of cigarettes. Nonsmokers can usually smell the cigarette odor intensely and, if in the presence of a smoker, can smell it not only in the smoker's presence but will continue to smell the odor on their clothes, hair and other items long after the two have parted. This same adaptation happens when wearing perfume or cologne: Within an hour of applying the fragrance, the wearer no longer smells the scent.
The feeling of hot and cold is an adaptation to the sensation of touch. A primary example is how quickly our bodies adjust to the water temperature when taking a bath. The bathwater may feel extremely hot when entering the tub; however, within minutes the water may feel cool to the touch. The water temperature has not changed significantly; our bodies have adapted to the temperature.
The taste buds in our mouth play a critical role during eating. Our tongues have approximately 2,000 to 8,000 taste buds divided into four basic tastes: sour, sweet, bitter and salty. When eating a specific food, the initial taste is very distinct and identified by the tongue's sensory neurons. As you continue eating the food, the taste is not as strong and does not have the same impact, which is due to sensory adaptation.