Other times it is barely noticeable, such as whether a toothbrush has 2,500 or 10,000 bristles.
What is the Just Noticeable Difference?
Just noticeable difference is part of a field of study known as psychophysics.
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Psychophysics examines how physical stimuli in the environment affect and interact with mental processes.
While scientists used to focus on measuring objective data, psychophysics allows them tomeasure subjective experiencesas data.
The just noticeable difference applies toall five senses: touch, taste, smell, hearing, and sight.
Difference Threshold vs. Absolute Threshold
The just noticeable difference is not the same as theabsolute threshold.
The absolute threshold for sound, for example, would be thelowestvolume level that a person could detect.
The just noticeable difference would be the smallestchangein volume that a person could sense.
Importance of JND
Difference thresholds can help researchers understandhow we respond to our environment.
The just noticeable difference also impacts our preferences.
Weber studied the just noticeable difference using weights to see when subjects could detect when the weight was different.
He discovered that we’re better at detecting relative differences.
To measure sensory information and difference thresholds, scientists rely on responses from study participants.
The measurements scientists take depend on the sensory information being received.
For instance, when measuring heat, researchers may use joules.
When measuring sound, they may use decibels instead.
Imagine that you present a sound to a subject and then slowly increase the decibel levels.
You increase the sound level by 7 decibels before the participant notices that the volume is louder.
In this case, the just noticeable difference is 7 decibels.
For example, imagine being in a dark movie theater.
Does Just Noticeable Difference Change?
The just noticeable difference does change throughout the day.
The amount and intensity of otherstimuli experienced beforehandalso affect how we perceive additional stimuli.
The smallest weight difference that can be detected at least half the time is the just noticeable difference.
They then press the button two more times before we can notice an increase in volume.
Taste
Maybe we drink ourcoffee with sugar in it.
Uses for the Just Noticeable Difference
The JND is often studied in product development.
Companies that create food products can also study the JND to understand consumer preferences.
Companies may take advantage of the JND in several ways.
For instance, a company may determine the JND of a price point.
This enables it to increase the price of a product so slightly that consumers likely won’t notice it.
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