The concept is a general term for the body’s recognition of external signals from the environment. Haptic perception refers to the way a person can gain information about his or her surroundings through touch. It involves skin sensors and receptors in other parts of the body such as muscles, which recognize sensations such as pressure. These work together to send signals to the brain, which interprets them to form a representation of the environment for the person to understand.
The kinds of differences in sensation that the body can recognize through touch are primarily mechanical, which is why many of the sensors important in haptic perception are called mechanoreceptors. These register changes in pressure and vibration. In addition to sensing mechanical changes, haptic perception also uses data from thermoreceptors that record changes in temperature.
The skin is an organ that protects the interior of the body from damage and infection, and also provides structure. In addition to these roles, the skin is home to both mechanoreceptors and thermoreceptors, because the outside of a person is the part that most often communicates with the environment. Receptors record sensations and send the data through the nerves to the brain. The brain collects all data from touch experiences, takes into account the prior knowledge of similar objects, and forms a concept for the element being touched.
Haptic perception does not only mean experiences from the skin. Mechanoreceptors are also present inside the body, in places that correspond to the environment. Basically, these are the muscles, joints and tendons, which undergo changes in position when a person touches an object or surface. For example, when a person presses a finger on a cake to see if it is cooked, the position of the muscles, tendons and joints of the finger varies with the suspension of the cake.
Generally, when a person is affected by something else, he or she will mainly concentrate on the resulting sensations on the body and neglect the physical properties of the moving element. In contrast, when a person touches something in the environment, he or she will form a perception of the physical environment. Haptic perception is usually used for the second situation, where the characteristics of the environment are important.
The roughness of a surface, the oiliness of a liquid, or the heaviness of an object, are all measures by which the brain arrives after interpreting signals from the receptors. Sometimes accurate haptic perception requires the person to move his or her skin to the surface, to judge differences in feeling such as roughness. Receptors that are at the bottom of the hair can recognize when a spider is crawling on one hand and in which direction it is scuttled. The size and shape of objects is also recognized through haptic perception. An example of this is a child digging blindly in a Halloween bag of candy to find his or her favorite lollipop, which can be round, flat and large, as opposed to small and spherical.
- Mechanoreceptors are involved in the body’s sense of balance.