Camera Rotation (FPC)

Hello!

Maybe this is a really stupid question, but since I can't get it right...

I'm currently using the First Person Controller. When pressing the space bar, I want the character to look down and back up. When I write something like that and attach it to the main camera, the camera only moves a little to the left or to the right. No matter what numbers I insert.

This is the code I'm currently working with:

 transform.rotation = Quaternion.Slerp(transform.rotation, target, Time.deltaTime);

Any ideas? :/