character more or less closer?

Are you talking about just the face or the whole body? If just the face there is a Head Scale Strength property of the face behavior. As you lean forward/backward it adjusts the scale of the head.

if you are talking about the whole body, then you can use the Transform behavior to change the scale, but that is not driven by the webcam.  Project Wookie, Episode 9: Moving Puppets Linearly - YouTube

If If you want the whole body to resize, there are tricks you can do. Basically you turn off all of the Face behavior settings of the root Face behavior except head scale strength, then mark the root of the puppet as the head. So the face behavior thinks the whole puppet is a head. Then on the real nested head, add a second face behavior to do all the normal face stuff. Hacks, but should work...