Photoshop CS5: can I retroactively determine adjustment parameters?

Photoshop CS5: can I retroactively determine adjustment parameters? E.g, the values used when I adjusted brightness/contrast?

I'm running Adobe CS5 on an iMac 24" (OSX 10.6.8).

Ive been working on picture in Photoshop. The first step was an adjustment of brightness/contrast. I can see the several steps I've made in Photoshop's 'history' window, but, although I can do or undo the various levels, I can't determine the values I used at each stage, as there appears to be no info on those values in the history window.

I've been making notes of the subsequent transformations/adjustments, but I didn't remember to do that on the first step. Can I retrieve this info somehow, via history, or some other way?

Thanks, Seb