jnd

Don Normans web site is called jnd.org and if you look close enough on the home page there is a reference that says What does “jnd” mean?. jnd refers to Just Noticeable Difference. Don explains it as “In the field of psychophysics, that branch of experimental psychology that studies sensation and perception, a jnd is the amount that something must be changed for the difference to be noticeable, defined to mean that the change is detectable half the time. My goal is to make a noticeable difference — many jnds worth — in human-centered technology.”

What jnds are you going to make today?