Tactile and visual sensations are able to adequately provide information on a variety of objects and phenomena of the surrounding environment, but they have different ways of perceiving.
Visual perception is based on a holistic vision of the subject, no matter how great and big it was, and the sense of touch when a person can perceive only parts of the subject.Due to the fact that the tactile perception is accomplished at a slower rate compared with the visual, tactile object image formed slowly.
Zone tactile inspection negligible.For the tactile perception of objects there are a number of obstacles, such as object size, its shape, humidity, temperature, etc.Even when using specialized hardware tactile examination is complete.All this affects the interaction between the blind and the environment.
However, the sense of touch is for the blind crucial because it is directly involved in the reflection o
Touch for the blind - the main method of objective knowledge of its living environment.It includes two groups of sensations: skin and movement.
to skin sensations include temperature, pain and tactile.
tactile sensations related to the contact, they appear when you touch anything, there is pressure on the skin of the subject in multiple undertaken an effort of tactile sensations.Receptors tactile sensations on the skin is uneven and therefore the threshold of sensitivity to each different area of skin.
Tactile sensitivity depends on the mass of different factors: reduced from bumps, cuts and other mechanical influences, changes depending on the temperature of the environment or the subject, the nature of the surface of a tangible object (eg, a convex object on a flat surface feels better than the thing with huge or smalldepressions).
Tactile sensitivity also depends on the strength and frequency of press, of human sentiments: when positive emotions sensitivity level above.
There are passive and active tactile sensitivity.Passive tactile sensitivity is carried out without moving your fingers or hands in the facility survey, and the active hands move.
temperature sensation of the skin associated with the sensation of heat or cold.Cold receptors in the skin more than the heat, so the skin is more sensitive to cold than to heat.Temperature
skin sensations may be contact and distant.The greater the temperature difference between the object and the skin, the greater the distance arise sensation of heat and cold.
Skin can feel not only the temperature of the object at a distance, but also to determine its position in space.For example, a blind person can determine the location of heating or lighting devices, the location of the sun in the sky, etc.The greater portion of the skin-sensing, the lower the temperature difference needed to distinguish objects.Temperature sensation
tend to adapt, and the larger surface of the skin, the degree of adaptation to the temperature regime above.For this reason, touch the subject must have a short duration, they are only informative.
speed and accuracy of this type of sensation depends on human experience in determining the water and air temperature.
Pain result from exposure of the skin mechanical, chemical, thermal stimuli.They inform the system that the site of action in the skin breaks or close to it.Painful sensations are the basis of self-preservation of the organism.
When the spatial orientation of the pain is not being used.
cutaneous sensations are blind to the huge flow of information about the objects of the world.With systematic training blind people can learn to recognize objects with ease.
Only one tactile sensitivity does not provide complete perception of objects.For complete information on object sizes must enable motor analyzer.Motor and tactile analyzers will complement each other.
Motor sensations are a significant body of information on the size and spatial arrangement.Engine Analyzer performs traffic management functions, its accuracy, speed and strength.Man feels the movement of the body and can control it.
Motor sensation in most cases, non-contact, contact motor sensations are possible only at low speed.Otherwise, such an effect may lead to injury.
movement sensations performs the function of measuring items and may allow to evaluate the size of objects, regardless of their size.
Thus, the whole system of skin-sensations motor at full or partial vision loss is becoming a major source of information about the environment.It contributes to better orientation in space, and its safety - a higher degree of mastery of the skills of orientation in the terrain.
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