Heres how to disable it.
If you still want to disable, heres how to do it.
On my MacBook Air, this setting kept fluxuating up and down.
Once here, poke the Change plan options link on the selected plan.
Then nudge the Change advanced power configs link.
And now, browse down to Display > Enable adaptive brightness, and change the controls there to Off.
Changing this setting fixed my brightness problems on my MacBook Air running Windows through Boot Camp.
