He and his friends are a merry bunch. They have also known eachother for quite some time. So, much so that when they raise their voices, their heads follow. The reasons for this have been evaluated by our best scholars, who have presented the following two expalanations for this.
One reason might be that upon singing they all began to search their surroundings for something; perhaps a corner, a picture, maybe a nail, or a squirrel; which might be a suitable resting place for their eyes during this joyous interlude. Yet all they find are wide stretches of snow covered plain. But wait.... Up above...Yes...The Stars. Therefore they gaze into the heavens. And what better place is there.
The other reason, which is disputed among some circles, is that because Charles and his friends have been doing this so long they have began to choreograph their movements, beginning with the head.
This strange behavior is not limited to the Peanuts gang only. Julie Andrews at the beginning of her career was timid, afraid to let her eyes sing with the notes.
But she quickly overcame these fears.
Others have found it hard to break the pressure by themselves. Stevie struggled for so long that he resorted to other means.
But in the end, it is up to you. You can continue to memorize your surroundings while your heart soars in song, or you can grab hold of the opportunity to observe others while they are all busy studying the nail that is protruding from the wall so drastically. This is quite enjoyable
What is important is to let it out. Sing it loud, Sing it Proud.