Tactile Discrimination

Tactile discrimination, as the name would imply, is the ability to discriminate between sensations by touch. In other words, tactile discrimination is the ability of your mind to process information gained through the sense of touch.

Significance

• Tactile discrimination involves a few key abilities of the mind to discriminate between sensations felt on the skin. These key abilities are two-point discrimination, sharpness, dullness, stereognosis and a special ability known as graphesthesia. Many diseases of the higher centers of the brain can be diagnosed by the specific loss of abilities of tactile discrimination.

Two-point Discriminations, Sharpness and Dullness

• A key feature of tactile discrimination is the ability of your mind to perceive two separate stimuli on different points of the skin when they are applied simultaneously. More specifically, the skin on your leg can normally differentiate between the touch of two pencil tips that are more than a few centimeters apart when they are placed on the leg simultaneously, but if they are placed closer, your mind will not be able to discriminate between them and will feel them as a single point. The ability to differentiate between sharp and dull objects is another key aspect of tactile discrimination.

Stereognosis and Other Special Abilities

• Stereognosis refers to the ability of the skin, typically the hand, to ascertain the shape of an object through touch alone. Stereognosis is demonstrated by handing a blindfolded person a cube and asking him what shape he is holding. A more specialized aspect of tactile discrimination is the ability to discern letters drawn on the skin with a blunt object. This ability is known as graphesthesia.