What is Absolute Threshold?
An absolute threshold is the smallest amount of stimulation required to detect 50% of stimuli. This is true for all our senses:
- Lightest intensity we can see
- The faintest sound we can hear
- The slightest touch
- But what does “50% of the time” mean in the definition? Why not always?
For example, background noise, expectation, motivation, and physical condition can all affect our absolute threshold. In perfect health, expecting a sound in a quiet room, is easier than being tired, unaware, and in a noisy street.
Signal detection theory states that there is no single absolute threshold. Because our perception responses vary, researchers run multiple tests until they find the amount that is perceived 50% of the time. Sensory adaptation is another factor that influences the absolute threshold. Sensory adaptation occurs when our bodies stop recognizing a stimulus after a long period.
Imagine entering a room with a loud air conditioner. The sound of the air conditioner may bother you at first, but after a while, you won’t notice it. Even if you weren’t previously aware of the air conditioner’s sounds, turning it off immediately makes a difference. This is a perfectly rational biological response because if a stimulus is perceived for a long time and nothing bad happens, it is not dangerous and can be ignored. That’s somatosensory.
What is Difference Threshold?
A difference threshold is basically defined as the minimum possible difference between two different stimuli demanded by a person to take note of any change half of the time. The concept is also known as the just noticeable difference threshold. Here are a few illustrations of thresholds:
- The lowest possible substitute in sound is to notice a substitute in the volume of radio.
- The lowest possible difference of weight between two sand piles that we can detect.
- The difference in light intensity between two light bulbs that we can perceive
- The minimum perfume quantity that is supposed to detect a change in smell
- The psycho-physicist Ernst Weber developed the Weber’s Law to appraise difference threshold. Weber’s Law states that in order to perceive any two stimuli as different, there ought to be a uniform percentage commute. In other words, the more intense a stimulus is, the more it must change to be noticed.
Assume that the manufacturers designed a poor system of volume where increase in each volume means a constant hike in the absolute (not percentage though) value. One can easily tell the change occurred between volume 1 and volume 3 but not between forty and forty-three. From the perspective of Weber’s Law, in order to discern the change in volumes 40 and 43 as one did in volumes 1 & 3 (a 300 percent hike), volume 40 has to be 120. (the exact hike of three hundred percent).
Difference Between Absolute Threshold vs Difference Threshold
- A stimulus’s absolute threshold is the lowest intensity that a person can detect with their senses. A difference threshold is a smallest or smallest difference that a person can detect between stimuli.
- The absolute threshold is calculated by recording the lowest intensity that a person notices for half of the period. Whereas, the difference threshold is calculated by measuring a higher and lower threshold and taking the average of the two readings.
- The absolute threshold is not a value determined by a person’s ability to detect and record a change in stimuli. The difference threshold is calculated by comparing the time it takes to notice a change in the stimulus to the time it takes to notice the smallest change.
- When determining the absolute threshold, the mean value is ignored. When determining the distance criterion, the mean value is applied.
- The absolute threshold is the lowest observed intensity. The distance threshold is the smallest variation between the observed intensities.
Comparison Between Absolute Threshold and Difference Threshold
| Parameters of Comparison | Absolute Threshold | Difference Threshold |
| Definition | It is the minimum range of stimulus that can be detected at least during half the time. The phrase is most used in neuroscience as well as experimental research to explain any kind of sensory input, including sound, touch, taste, sight, and smell. | The difference threshold is the smallest change that is required for someone to notice it 50% of the time. It includes all five senses. It is the minimum light difference that is needed to notice. |
| Illustration | In a particular sound detention experiment, scientists may play a sound at different volumes. The absolute threshold is the smallest level an individual can hear. | A difference threshold is the ability to differentiate between two different hearing tones. |
| How it is measured | An individual is exposed to a signal at different levels and then asked to tell whether or not they can acknowledge it. The absolute threshold value is the lowest or minimum intensity that an individual can intercept 50% of the time. | The upper value is the difference among the intensity and 3/4 of all trials, while the lower value is the difference among the intensity and 3/4 of all trials. |
| Stimulus’ condition | The stimulus intensity remains the same while defining the absolute threshold. | The stimulus intensity changes in order to figure out the difference threshold. |
| Application | The absolute threshold can lead to food development. | Marketers might use the difference threshold to figure out the most cost-effective way to further improve their strategies. |