Human beings, although we are members of the same species and resemble each other in many ways, also have great individual differences from one another. Sensory thresholds play a key role in resolving these differences, Since these are the limits that each person must tolerate a given stimulus.
In this article, we’ll go over this concept and break down the most relevant aspects of it.
What are the sensory thresholds?
Sensory thresholds refer to the degree to which a subject responds to a given stimulus, Given the intensity required to notice it and make it boring, among other parameters.
This is determined by the magnitude between the so-called thresholds, which are composed of minimum thresholds and maximum thresholds. The lower a person’s threshold for a specific stimulus, the lower the level of tolerance they will present to it. The opposite occurs when the tolerance threshold is high; in this case, the subject is very tolerant to the stimulus, and may even become hyposensitive to it.
We then understand that the sensory thresholds these are basically the margins of our sensations.
Let’s see what happens when a person’s thresholds are at one of the limits, whether it is the upper limit (higher stimulus tolerance) or the lower limit (lower stimulus tolerance).
1. Limit threshold or upper limit
It refers to the breaking point between tolerance and intolerance. After this point, any increase in stimulation has an unbearable effect on the subject., Which will inevitably have to give in in its resistance.
2. Absolute threshold or lower limit
This consists of the minimum degree of sensation that must exist for the subject to perceive the stimulus. A lower intensity in terms of the level of the stimulus would go unnoticed by the person because they would not be able to perceive it.
In each of these cases, a number of interfering factors that may be biological or even related to social circumstances, the education of the subject and the environment in which he develops on a daily basis.
This means that no person has absolute sensation thresholds, that is, they are not permanent, but they are subject to change depending on the personal situation of each individual.
What is the differential threshold?
The differential threshold is the minimum difference in intensity of a stimulus that must be given because the subject is aware of the difference on one of the two occasions, or 50% of the time.
On the other hand, the differential threshold the greater the magnitude of the stimulus. For example, adding 15 grams to one of the two objects weighing 50 grams may make you notice the difference in weight between the two, but if you add them to one of the two objects weighing 5 kilograms, you will not notice the difference. , since the threshold differential is higher in this second case.
These are the main theories of sensory thresholds.
1. Psychophysical theory
This theory has focused most of its research in the area of absolute value, the same as the minimum threshold, leaving out other relevant aspects of how sensations are perceived by the subject.
2. The modern theory of signal detection
Regarding this theory, there is a significant variation compared to the previous one, because the threshold is not taken into account. The emphasis is on signal detection whether or not the subject notices that he is receiving a stimulus.
This is achieved using sophisticated measuring instruments, specially designed to quantify the intensity of a given signal received by the body, even if it is imperceptible to the subject’s consciousness.
Methods used to detect the stimulus
The following methods are generally used when researching in this area.
1. Limits method
It consists in determining, using approximate calculation, to the point that it may be closer to the absolute threshold you want to find.
2. Method of constant stimuli
In this case, the subject is subjected to random stimuli. In other words, they are not used in ascending or descending order. They are just constantly testing new stimuli and recording the results.
3. Mean error method
In that case it must be the assessor or the assessed subject himself who manipulates the intensity of the stimuli it receives, until a significant change in sensation occurs.
- Bialek, W. (2012). Biophysics: a search for principles. Princeton University Press. p. 40.
- Levine, M. (2000). Fundamentals of sensation and perception. London: Oxford University Press.