Each individual’s perception of reality is created through information received by sensory receptors in the human body. This information is transferred to the brain through electrical signals, which it receives and interprets as experiences.
Key Takeaways
- The absolute threshold is the minimum level of stimulation required for a person to detect a sensory stimulus. In contrast, the difference threshold is the minimum difference in stimuli required to detect a change.
- The absolute threshold is constant, while the difference threshold varies depending on the magnitude of the stimuli.
- Absolute threshold is useful in understanding the sensitivity of our senses, while difference threshold is useful in understanding the ability to discriminate between different stimuli.
Absolute Threshold vs Difference Threshold
The difference between the absolute threshold and the difference threshold is that the absolute threshold is the minimum amount of stimulation that one can interpret or perceive. In contrast, the difference threshold is the minimum amount of change required in the intensity of a stimulus for someone to be able to interpret a difference.
Psychophysicists often use the term ‘threshold’ while dealing with sense and perception.
Threshold means the limit values in which an individual perceives or interprets something. For example, there is a minimum value at which someone can perceive a certain stimulus. This value is a threshold.
Comparison Table
| Parameters of Comparison | Absolute Threshold | Difference Threshold |
|---|---|---|
| Meaning | The absolute threshold is the minimum amount of stimulation an individual can interpret or perceive. | The difference threshold is the minimum amount of difference in the intensity of a stimulus for someone to be able to interpret a change. |
| Condition of stimulus | There is no change in the intensity of the stimulus while determining the absolute threshold. | There needs to be a change in the intensity of the stimulus while determining the difference threshold. |
| Determined value | The determined value specifies the smallest amount of intensity. | The determined value specifies the smallest amount of change in intensity. |
| Distinctness | The absolute threshold also varies among people and between people and animals. | There is only a slight variation between the different thresholds of different people. |
| Example | The minimum distance at which a person can see a candle burning clearly. | The minimum amount of difference in the distance required for a person to notice the change in position. |
What is the Absolute Threshold?
Initially, according to the studies of neuroscience and psychophysics, absolute threshold referred to the minimum intensity level of a stimulus at which a person’s sense receptors could perceive it.
For example, the lowest volume at which one can hear, the shortest distance till which one can see, the smallest amount of concentration of a fragrance that one can smell, and so on.
However, it was later observed that internal or external factors could influence the absolute threshold of a person. For example, an individual can taste food easily when the level of health is good.
But on catching a slight cold, the intensity of taste while eating the food decreased. This made it difficult to determine the individual’s absolute threshold, as health conditions are prone to change at different times.
To counter this problem, it was decided to change the definition and method of determining one’s absolute threshold. Now, physicists would conduct multiple tests on a person over a certain period.
The value which came out to be true fifty per cent of the time would be referred to as the person’s absolute threshold. Presently, the absolute threshold is the smallest amount of intensity at which an individual can perceive a stimulus fifty per cent of the time.
The idea which influences this modification is known as the single detection theory. It states that there is no absolute threshold because of other influencing factors.
What is the Difference Threshold?
The difference threshold is the minimum amount of difference required in the intensity of a stimulus for an individual to perceive or detect a change. It is also called ‘Just Noticeable Change’ (JND).
Like absolute threshold, a person should be able to detect the same value at least fifty per cent of the time.
Some examples of different thresholds are – the smallest increment in the intensity of sound for one to detect a change in the television’s volume, the minimum amount of distance at which a person can see an object, the minimum amount of heat required for one to feel that the food is hot, and so on.
Weber’s law is a significant law of psychology that quantifies the detection of change regarding a certain stimulus. According to the law, as the intensity of a stimulus increases, it becomes more and more difficult to perceive a change or difference.
For example, if the volume of a television set is already very high, it would be difficult for a person to detect whether or not the volume has been increased further. To have a clear understanding of Weber’s law, imagine a television set which is playing at volume 5.
Now, if it changed to volume 10 (an increase of 100%), the difference in sound would be noticeable. However, the change in sound between volumes 50 and 55 will not be the same value. For a person to be able to notice it, volume 50 will need to be changed to volume 100 (an increase of 100%).
Main Differences Between Absolute Threshold and Difference Threshold
- The absolute threshold is the minimum amount of intensity required for one to be able to detect a stimulus. In contrast, the difference threshold is the minimum amount of difference in intensity required for one to be able to detect a change.
- Unlike the difference threshold, the absolute threshold does not involve any change in the intensity of the stimulus.
- The absolute threshold determines the minimum intensity value, while the difference threshold determines the intensity change value.
- The absolute threshold varies largely from person to person and animal, whereas there is only a slight variation in the different thresholds of different people.
- The absolute threshold is the minimum volume at which a person can detect sound. On the other hand, the difference threshold is the minimum amount of change in the volume for a person to detect it.
References
- https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1750-3841.2011.02589.x
- https://ieeexplore.ieee.org/abstract/document/7476866/
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.
