Whenever the concept of perception and stimulation by the human mind and senses are being discussed, there are 2 aspects that are often mentioned.
The first is the absolute threshold that focuses on the lowest amount of stimulation that a person can detect half of the time.
The second is the difference threshold that aims at determining the change needed for a difference in something to be detected.
We discuss the difference threshold in depth here to see how it works and understand it better.
What is The Difference Threshold
The difference threshold is the amount of change needed for a person to perceive a difference in something.
This type of threshold is around us almost every time.
When you are watching a movie and you feel the volume is too low for you to hear well, you go ahead and turn up the volume.
Supposing the volume was at 30, you may need to hit 40 or 50 to feel that the volume is now good for you to enjoy the movie.
See, as you were increasing the volume, you went from 30 to 31 and 32, but you didn’t feel like there was any change in the volume, yet there was.
Although it was very little.
It took you increasing the volume all the way to 40or 50 to notice the actual increase in volume in your ears.
That is the difference threshold.
The amount of change in volume you need for you to perceive the increase in volume from what you had to the volume you felt was a bit better is your difference threshold.
Another example is when you are holding up a jug or a big container with little water in it using your hands and someone is adding water to the vessel slowly by slowly. You might not be able to detect the change for the first few drops of water added to the vessel.
However, as the water in the vessels keeps increasing, you will start to feel the container or the jug to be a little heavier than it was when you started out. That is the difference threshold.
The difference threshold applies to all of our areas of perception, including the 5 human senses, sight, smell taste, hearing, and touch.
Anything you can hear, touch, smell, taste, or see has a difference threshold when something is added or taken away from it long enough to notice a difference.
The difference threshold is also referred to as The Just Noticeable Difference (JND), Difference Limen (DL), or the discrimination threshold.
The idea of the difference threshold was first explained by Ernst Heinrich Weber. He was an experimental psychologist and physiologist.
It was later expounded by Gustav Fechner. That is what the Weber-Fechner law, which is also known as Weber’s law, is based on.
Understanding The Difference Threshold Better
On the hearing, the difference threshold may seem quite similar to the absolute threshold, but these are two different concepts.
The absolute threshold is the lowest level of stimulation that a person can discern 50% of the time.
An example of absolute threshold is when a gong is hit from a far distance and a person who is far away from it tells if he can hear the sound from the farthest distance possible.
Suppose he can’t hear as he is too far. He then makes a few steps towards the gong to determine if he can hear the sound.
For a good distance, he may not be able to hear the sound of the gong but as he gets closer, it becomes audible.
As he keeps coming towards the gong, the lowest level of sound he can hear when he is as far as possible is the absolute threshold.
On the other hand, the difference threshold is the amount of change that is required for a person to perceive a difference in a stimulation 50% of the time.
This is where a change is taking place but it is so toned down that you cannot detect it. But as it keeps happening, your senses are able to make a detection of the change at a certain point.
That “certain point” is the difference threshold.
As earlier said, the difference threshold involves all senses. Let’s take a look at an example of the difference threshold with each of the 5 human senses.
The difference threshold in vision
The difference threshold in vision is the amount of change that you require to sense a difference in something, visually.
Say you are looking at a number for workers offloading sand from a truck to a place where some construction is about to take place.
You found them halfway through the job. You see some sand on the site and more in the truck from they are offloading using shovels.
Now if you stare at them throwing the sand down to the site and see them throwing one shovel of sand each, it is hard to see a difference in the amount of sand on the site.
At the back of your mind you know there is an addition of sand but your eyes can’t see the change since it is so small.
However, if you hang around for about 30 minutes you will detect an overall increase in the amount of sand on the site with your eyes.
That is the difference threshold for vision.
The difference threshold for touch
The difference threshold for touch is the change required for you to sense a difference using your sense of touch.
Let’s use the same example of sand, but this time you are holding small amounts of it in your hands.
Your friend comes and starts adding some more sand in your right hand and tells you to say when you start feeling that your right hand is getting a bit heavier from the increase in the sand in that hand.
The tiniest difference in weight that you can make detection of, half of the time, is the difference threshold for touch.
The difference threshold for smell
Imagine you are in a room with two people who are spraying perfume on themselves. You can smell the two perfumes and they are somewhat equally strong on your smelling sense.
One of them decides to spray themselves some more but slowly so that they don’t overdo it.
The percentage of perfume that it will take for you to notice that the strength of the perfume of the person who decided to spray more themselves is now stronger than the other person is what is referred to as the difference threshold for smell.
The difference threshold for taste
You have tea in your mug that has very little sugar in it. You taste it and felt that the amount of sugar in there is just not enough to excite your taste buds.
So you decide to get the sugar from the kitchen and add a couple of spoonfuls. After the first spoonful, you feel like there is no difference in the taste since your mug is big.
So you add some spoonfuls and maybe after the fourth, you feel that the taste is now starting to taste sweeter.
The amount of added sugar that it takes for you to notice the increase in the sweetness of tea is the difference threshold for taste.
The difference threshold for hearing
You are busy listening to the radio at low volume as you chill on your bed. You suddenly hear your favorite music and you want to listen to it in the best possible volume for your ears.
So you reach out for the radio’s remote and start increasing the volume.
It was initially at 20, so you bring it up to 25 but can’t really notice the increase in the sound. You increase it to 35 and start feeling it is getting a bit louder now.
The decibels it took for you to notice the increase in volume is the difference threshold for hearing.
Research on the difference threshold has helped us learn more about our responses to difference threshold through our senses and it has also helped in various aspects of life such business and improvement of products (3)(4)(5)(6)(7)(8)(9)(10)(11).