Duration and speed of the animation
When elements change their state or position, the duration of the animation should be slow enough to give users the possibility to notice the change, but at the same time quick enough not to cause waiting.
Numerous researches have discovered that optimal speed for interface animation is between 200 and 500 ms. These figures are based on the particular qualities of the human brain. Any animation shorter than 100 ms is instantaneous and won’t be recognized at all. Whereas the animation longer than 1 second would convey a sense of delay and thus be boring for the user.