One of the most important parts of psychology is Functional analysis between physical stimuli and effector or open (internal) responses, which has given rise to the establishment of laws psychophysics. The study of publicly observable stimuli and responses has allowed us to understand the conditioning sensorimotor. But one may also be interested in knowing how external stimuli produce internal responses, which would be subjective experiences only accessible through introspective processes, this is the case of sensations.
Constants and Weber’s law
Psychophysical laws are based on one of the few constants found in psychology. Ernst Heinrich Weber, German physiologist, founder of psychophysics, discovered that, in sensoryity, we perceive relative, not absolute, changes in the intensity of stimuli. What he did was relate the increase in the stimulus when a precisely perceptible sensory difference occurs.
So, if we call the physical value corresponding to the differential threshold or djp ΔE (increase in stimulus intensity) Relative sensory discrimination must be defined as ΔE / E = Weber Fraction and expresses the relationship of the increase in intensity that said stimulus had before a djp could be perceived. Weber’s Law Weber discovered that this fraction was equal to a constant, for different values of stimulus intensity k = Weber’s constant, giving rise to the so-called Weber’s Law.
Weber’s Law = Every stimulus needs to be increased in a constant proportion of its magnitude, for a change in sensation to be perceived. But such a fraction is not really constant since as the stimulus values approach the absolute and terminal thresholds, the fraction changes and the law is not fulfilled (it is fulfilled for moderate or intermediate values) since the increase in the stimulus grows in a greater proportion. than the stimulus, and the fraction is not constant but consequently increases.
To correct this defect, a corrective factor was added to its law consisting of the value “to” which is a small constant quantity that is related to the value of the stimulus, leaving Weber’s law K = ΔE / (E + a). When the stimulus value is very small, then “to” It has enough weight to produce a significant modification in the value of the fraction but not at medium stimulus intensities. This modification is by GA Miller. Problems arise around its interpretation. The final conclusion is that Weber’s law states two things:
- That relativity is the principle of sensory intensity. The differential threshold increases when the stimulus value increases, that is, ΔE increases when E increases.
- That Weber constant It differs markedly from one sensory modality to another. Weber’s constant is used to determine the acuity or subtlety of the different sensory modalities.
The magnitudes that are related are always measured on the physical continuum, therefore, many authors do not consider this law a psychophysical law in the strict sense, but rather a law that relates the physical with the physical. This is not entirely correct since the increase in the stimulus is determined by the justly perceptible differences (djp), which are already subjective experiences.