What Are Two Types of Sensory Adaptations?

Sensory Adaptation

• When a particular sensory stimuli changes, the results can be jarring: jumping into a swimming pool full of cold water on a hot day, for example. Staying in the water, however, will gradually lead you to become acclimatized to the water temperature. Another example of sensory adaptation occurs when you eat a food that is spicy. At first, the experience may be unpleasant, even painful. As you continue to eat, you become accustomed to the spiciness.

Adaptation to Darkness

• One of the most common types of sensory adaptation is when you leave a lighted area and enter a darkened room, such as walking into a movie after it's already started. The immediate effect is disorientation as your eyes perceive nothing but darkness. Gradually your eyes adjust and you're able to see things around you. This occurs when a chemical called iodopsin in the eyeballs' rods and cones changes in concentration to increase the eye's sensitivity to reduced amounts of light. The cones react in about 10 minutes, while the rods take about half an hour to fully adjust. Sensory adaptation occurs gradually because time is required for the body to produce the additional iodopsin needed by the rods and cones to adapt to the new darkened environment.

Adaptation to Light

• Adaptation to light is the exact opposite reaction to adaptation to darkness, occurring when you leave a darkened environment to enter an area that is brightly lit. An example of light adaptation would be exiting a darkened room and going outside on a sunny day. In this case, the excess amounts of iodopsin cause the eyeballs' rods and cones to become oversensitive to normal light until the eyes readjust by reducing iodopsin concentrations back to normal levels.

Adaptations to Sound, Touch and Smell

• Another example of sensory adaptation is when a loud noise causes a small muscle in the inner ear to contract, a protective mechanism that reduces the transmission of sound vibrations to the inner ear. Another involves the sense of touch, such as the way a heated bath that at first feels almost too to enter eventually fees too cool. Through the sense of smell, we can usually detect very low concentrations of odors in the air, such as perfume, but if the perfume remains in the air, we quickly become acclimatized to the smell and will stop detecting it.