basic psychophysical law is connected with the name of Gustav Theodor Fechner (1801-1887 gg.) - German physicist, psychologist and philosopher, founder of psychophysics.In his work "Elements of psychophysics" (1860), he puts forward the idea that science needs a new area of knowledge that studies the relation of physical and mental phenomena.This idea subsequently had a great influence on the development of experimental psychology.Research is carried out in the field of sensations, Fechner allowed to justify his famous psychophysical law of Weber - Fechner.
Fundamentals same law associated with the experiments of Ernst Heinrich Weber (1795-1878) - German anatomist, physiologist, the founder of scientific psychology, along with scholars such as Wundt, Ebbinghaus G. et al. Weber's idea of measurement in psychological science.
first studies
beginning, defined by the law of Weber - Fechner, E. Weber began research in the field of visual and auditory sensations, as well as in the field of skin sensitivity (touch).In particular, Weber belong to experiments with temperature sensitivity of the body.
example, discovered the effect of so-called thermal adaptation.When one hand is first placed in cold water, and the other - in hot, then after that the warm water for the first hand will seem warmer than the second, not adapted.
types of skin sensations Weber
In 1834, Weber formulated his ideas on the skin sensations ("On the sense of touch").Scientist identifies three types of data sensations:
- feeling of pressure (touch);
- sense of temperature;
- sense of localization (spatial location of the stimulus).
owned development esthesiometry Weber (Weber's compasses).With this device you can evaluate a sufficient distance to distinguish two simultaneous touches the surface of the skin test.Researchers have found that the magnitude of this distance is not the same, its importance for the various parts of the skin is different.Thus, the so-called Weber determines circles sensations.The idea that human skin has different sensitivity, also had an impact on the law of Weber - Fechner.
wording
frameworks, determine the psychophysical law of Weber served as research in the field of relations of sensations and stimuli (1834).It was found that for the new stimulus was perceived as different from the previous one, he must be opposed to the original stimulus by a certain amount.This value is a constant proportion of the original stimulus.Thus, the following formula was derived:
DJ / J = K,
where J is the original stimulus, DJ - the difference between the new and the original stimulus, and K - is a constant depending on the type of the impacted receptor.For example, to distinguish between light stimuli required proportion of 1/100 to sound stimuli - 1/10, and to distinguish between weight - 1/30.
Subsequently, based on the experimental data G. Fechner defines the basic formula psychophysical law: the magnitude of change is proportional to the logarithm of the sensation of the stimulus.Thus, the relationship between the intensity of feeling and the strength of the stimulus to which the law is directed Weber - Fechner, expressed as follows: the value of the intensity of the sensation varies in arithmetical progression, while the value of the intensity of the corresponding stimuli changes in geometric progression.
Limitation Act
despite objective research, psychophysical law of Weber - Fechner has a certain convention.It was found that subtle sense of constant values are not.For example, you can not argue that barely discernible difference in the sensations when exposed to loads of 100 g and 110 g similarly barely noticeable sensation when exposed to loads of 1000 g and 1100 Accordingly, the law of Weber - Fechner is characterized by a relative value, especially forthe average intensity of the stimuli.In turn, the data within the law is of great practical importance.
