Ctrl-U toggles Camera RAW "Use Auto Adjustments" on and off.
You can take that a step further and make a basic set of adjustments and save them then, after restarting Bridge, it will show up when you right click an image. I've got a set I use all the time for studio work which sets the WB, opens the shadows and notches the exposure up a half stop... makes the thumbnails easier to view. You can even save that as your default camera raw settings. Instead I leave them zeroed and just select all the images in a newly loaded folder and apply the 'open shadows/+1/2 stop' with a right click.