Absolute Threshold Vs. Difference Thresholds

Examples of Absolute and Difference Thresholds can be said that as it is related to Hearing, Smell, Touch, taste, and many more. For instance, in the case of hearing the ticking of a watch in a quiet environment, in the case of smell, one drop of perfume in a room is very valuable as it will change every factor of dependence on the type and variety of substance that the people within the room are smelling. In the case of touch, the slightest distance will surely matter, depending on or varying on the particular part or portion of the body involved. In the case of taste, for example, it depends on a slight drop of alcohol on the surface of water or any other liquid like, for instance, milk. These are some examples of Absolute Thresholds.

What is Absolute Threshold?

An absolute Threshold is the minimum amount of energy required or necessary to stimulate the sensory receptors of an individual. Different sensory systems can be tested using a similar methodology to determine the absolute threshold. As a result, the tester can briefly exhibit light, sound, or any other sort of stimulus at various low intensities until the observer cannot discern the stimulus's presence. The subject may go through thousands of trials in such a task before the researcher can establish the threshold. Although the absolute threshold is a valuable idea, it does not exist, implying that a person could occasionally be unable to notice a particular weak light.

What is Difference Threshold?

The smallest difference between two stimuli that must exist for a subject to observe change 50% of the time is known as a difference threshold. The phrase "just observable difference" also refers to the difference threshold and more accurately explains the idea. Some of the particular examples of Difference Thresholds in our daily life are: When we hear the slightest shift in sound, we notice a volume change on the radio. The smallest weight variation would allow us to notice a difference between two sand piles. The smallest change in light intensity allows humans to distinguish between two light bulbs. We only need to alter the amount of salt in a soup by a tiny amount to notice a difference in flavor. The smallest difference in scent concentration at which we can detect a difference in the smell of something.

Importance of Thresholds

Utilizing two thresholds enhances the chances of treating problems early, preventing performance decline and possibly downtime, and raising awareness of the system state.

Difference Between Absolute Threshold and Difference Thresholds

The lowest level of intensity of a specific stimulus that a person may perceive with their senses is known as an absolute threshold. The smallest or smallest difference between stimuli a person can detect is known as a difference threshold. The lowest intensity a person notices 50% of the time is recorded as the absolute threshold value. The difference threshold is calculated by taking the average of two measurements—an upper and a lower threshold.

The absolute threshold is not a number dependent on how much a subject notices and records a stimulus change, and the difference threshold is based on detecting the smallest change and a change in the stimuli.

The mean value is not used when measuring the absolute threshold, and the mean value is used when measuring the distance threshold. The minimum intensity noted is the absolute threshold, and the smallest difference in intensities recorded is called the distance threshold.

Factors Affecting Absolute Threshold and Difference Thresholds

It is often observed that the absolute threshold can be influenced by several factors, such as the subject's motivations and expectations, cognitive processes, and whether the subject is adapted to the stimulus. In the other case scenario, it has also been observed that certain factors affect Difference Thresholds. Nevertheless, in this case, the main factor affecting the Difference Thresholds is the total amount of change and evolution in a stimulus that is very much needed to form or produce a difference that other people easily notice. It could be of any form, whether a living or non-living organism. The state for Difference Thresholds should be timed with the sensation, in case it is a living organism.

Just Noticeable Difference

The smallest change that can be consistently noticed between two stimuli. The external world is presented to us in the form of ever-changing experiences. We are continually called upon to respond to little alterations in noises, colors, forms, and sizes. We could not appreciate a brilliant picture, drive securely, play a terrific game of tennis, or perform any precise task if we could not make fine distinctions. It is also critical to determine how sensitive we are to differences—that is, what is the smallest variation in length, loudness, or brightness that we can detect? This was most likely the first empirically solved question in the history of psychology.

Ernst Weber, a German scientist, established a technique for measuring the JND, or differential threshold, for distinct senses early in the nineteenth century. For example, to determine the IND for weight, he would have a subject repeatedly hoist an unmarked weight of, say, 300 grams and then heft different weights until he found one that was just significantly heavier than the given weight on 75% of the trials. The result was then expressed as a percent: if the new weight were 306 grams, the "Weber fraction," later dubbed, would be 0%.

He repeated the experiment with other weights and discovered that if the base weight was 600, the JND weight was 612, and if the base weight was 200, the JND weight was 204. When he calculated the proportion in each case, he made the shocking revelation that it was precisely the same in every situation—that is, Weber ran experiments on different senses and discovered a constant fraction for each of them. He discovered, for example, that if he started with 60 lighted candles, it only required one more candle to make a notable impact, and it needed two candles if he started with 120, and so on. In each example, the percentage was 0%. This discovery led to Weber's Law, initially presented in 1834, which stated that the lowest discernible increase in perceived intensity is a constant percent of the original stimulus. Weber's Law has been proven true for all senses, with some fluctuation, but only in the middle range of intensity.


From the above study in the research project, it can be concluded that both the absolute and difference threshold can be used to assess a person's sensory abilities. The lowest stimulus intensity that a person can consistently perceive is the basis for an absolute threshold. A difference threshold is based on the smallest change in stimulus intensities that a person can detect. This is why understanding the idea of Absolute and Difference Thresholds is very important to understanding and analyzing the behavior of any human. At the same time, understanding the merely perceptible difference in comparison to the absolute threshold is crucial. The absolute threshold is the lowest level of stimulation that can be detected, as opposed to the difference threshold, which is the merely perceptible difference between two stimuli. Although certain factors are responsible for affecting both the Absolute and Difference Thresholds, it is highly recommended to keep track of the change in the situation to determine the consequences of any action.

Updated on: 09-Dec-2022

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