只是明显的差异（JND）在心理学中万博maxbetx官网登陆

The just noticeable difference (JND), also known as the difference threshold, is the minimum level of stimulation that a person can detect 50 percent of the time. For example, if you were asked to hold two objects of different weights, the just noticeable difference would be the minimum weight difference between the two that you could sense half of the time.

It is important not to confuse the just noticeable difference and theabsolute threshold. While the difference threshold involves the ability to detect differences in stimulation levels, the absolute threshold refers to the smallest detectable level of stimulation.

The absolute threshold for sound, for example, would be thelowest volume level一个人可以检测到。只是明显的差异是最小的change in volumethat a person could sense.

Development of the Concept

The difference threshold was first described by a physiologist andexperimental psychologistnamed Ernst Weber and later expanded upon by psychologist Gustav Fechner. Weber's Law, also sometimes known as the Weber-Fechner Law, suggests that the just noticeable difference is a constant proportion of the original stimulus.

For example, imagine that you presented a sound to a participant and then slowly increased the decibel levels. You had to increase the sound level by 7 decibels before the participant could tell that the volume had increased. In this case, the just noticeable difference would be 7 decibels. Using this information, you could then use Weber's law to predict the just noticeable difference for other sound levels.

实际上，实际上明显的差异可能会在试验中各不相同。这就是为什么JND通常由进行米ultiple trials然后使用参与者可以检测到至少50％的最小级别。

刺激的强度水平也可以在人们注意到更改的情况下发挥作用。如果光线非常暗，人们可能更有可能注意到强度的更小的变化，如果与那些相同的变化是更明亮的光线。

例如，想象一下，你在黑暗的电影院。房子灯慢慢开始打开，您立即注意到光强度的变化非常小。之后，你离开剧院和阳光明亮的地方。如果外面的光强度的相同变化，则可能不太可能注意到它们，因为刺激水平要高得多。

只有明显的差异适用于各种各样的感官，包括触摸，味道，气味，听觉和视线。它可以适用于亮度，甜味，体重，压力和噪音等的东西。

Examples

• 想象一下，你为一个志愿者psychology experimentat your school. The researchers ask you to hold two small amounts of sand in each hand. An experimenter slowly adds tiny amounts of sand to one hand and asks you to say when you notice that one hand feels heavier than the other. The smallest weight difference that you can detect at least half the time is the just noticeable difference.
• 您正在与您的配偶看电视，但音量太低而无法听到。你问你的配偶转动。他按两次卷按钮，但你仍然无法判断卷的差异。在您能够注意到卷的增加之前，您的配偶再次按下按钮两次按钮。
• You are having a party at your apartment and the neighbor comes over and asks you to turn the music down. You and your guests immediately notice that the music is much quieter, but your neighbor does not notice a difference in the volume because the change is below his difference threshold.
• You volunteer for another psychology experiment at your school. This time, the experimenters place small amounts of sugar in a container of water and ask you to drink it. You are asked to say when you notice the sweetness of the water versus the plain water. The smallest level of sweetness you can taste half the time is the difference threshold.