EMOTION
The personality of a character is conveyed through emotion and emotion is the best indicator as to how fast an action should be. A character would not do a particular action the same way in two different emotional states. When a character is happy, the timing of his movements will be faster. Conversely, when sadness is upon the character, the movements will be slower. An example of this, in Luxo Jr., is the action of Jr. hopping. When he is chasing the ball, he is very excited and happy with all his thoughts on the ball. His head is up looking at the ball, the timing of his hops are fast as there is very little time spent on the ground between hops because he can’t wait to get to the ball.
After he pops the ball, however, his hop changes drastically, reflecting his sadness that the object of all his thoughts and energy just a moment ago is now dead. As he hops off, his head is down, the timing of each hop is slower, with much more time on the ground between hops. Before, he had a direction and a purpose to his hop. Now he is just hopping off to nowhere. 1
To make a character’s personality seem real to an audience, he must be different than the other characters on the screen. A simple way to distinguish the personalities of your characters is through contrast of movement. No two characters would do the same action in the same way. For example, in Luxo Jr., both Dad and Jr. bat the ball with their heads. Yet Dad, who is larger and older, leans over the ball and uses only his shade to bat it. Jr., however, is smaller, younger, and full of energy, he whacks the ball with his whole shade, putting his whole body into it.