Human beings, although we are members of the same species and alike in many ways, also have great individual differences from one another. Sensory threshold plays a fundamental role in terms of these differences , since they refer to the limits that each person has to tolerate a given stimulus.
What are sensory thresholds?
Sensory thresholds refer to the degree to which a subject reacts to a given stimulus , taking into account the intensity needed to perceive it and become irritating, among other parameters.
This is determined by the magnitude that exists between the so-called limits, which are composed of minimum and maximum limits. The lower a person’s threshold in terms of the specific stimulus, the less tolerance it will present to the person. The opposite occurs when the tolerance threshold is high; In this case, the subject has a lot of tolerance for the stimulus and may even become hyposensitive to it.
It is then understood that the sensory thresholds are basically the margins of our sensations .
your limits
Let’s see what happens when a person’s thresholds fall within one of the thresholds, either the upper threshold (greater stimulus tolerance) or the lower threshold (lower stimulus tolerance).
1. Terminal threshold or upper limit
It refers to the breaking point between tolerance and intolerance. After that point, any increase in stimulation has an unbearable effect on the subject , who will inevitably have to give way in his resistance.
2. Absolute threshold or lower threshold
This consists of the minimum degree of sensation that must exist for the subject to be able to perceive the stimulus . A lower intensity in terms of stimulus level would go unnoticed by the person, as he would not be able to perceive it.
In any of these cases, they interfere with a series of factors that may be biological or even related to social circumstances, the subject’s upbringing and the environment in which he operates on a daily basis.
This means that no person has absolute limits of sensation, that is, they are not permanent, but are subject to change depending on the personal circumstances of each individual .
What is the differential threshold?
The differential threshold is the minimum difference in the intensity of a stimulus that must be given for the subject to notice the difference on one of two occasions, that is, 50% of the time.
On the other hand, the differential threshold is greater the greater the magnitude of the stimulus . For example, adding 15 grams to one of two objects that weigh 50 grams can make you notice the difference in weight between the two, but if we add them to one of two objects that weigh 5 kg, the difference will not be noticed, because the threshold differential is higher in this second case.
Related theories
These are the main theories of sensory thresholds.
1. The psychophysical theory
This theory concentrated most of its research in the field of absolute value, the same known as the minimum limit, leaving aside other relevant aspects of how sensations are perceived by the subject.
2. The modern signal detection theory
Regarding this theory, there is an important variation in relation to the previous one, since the threshold is not taken into account. Emphasis is placed on detecting the signal, regardless of whether or not the subject is aware that they are receiving a stimulus .
This is achieved through sophisticated measuring instruments, specially designed to quantify the intensity of a given signal that the organism received, even if it is imperceptible to the subject’s consciousness.
Methods used for stimulus detection
When researching this area, the following methods are often used.
1. Method of limits
It consists of determining, using rough calculation, the point that may be closest to the absolute limit you want to find .
2. Constant stimuli method
In this case, the subject is subjected to the stimuli at random. That is, they are not used ascending or descending. New stimuli are simply being tested constantly, and the results are recorded.
3. Average error method
In this case, it must be the evaluator or the subject himself who manipulates the intensity of the stimuli he receives, until there is a significant change in sensation.