She 'played/acted dumb' [=pretended to know or understand less than she really did] so we would assign her the easier tasks.
She thinks television is contributing to the 'dumbing down' of America.
Cutting training programs will 'dumb down' the American workforce.
(..) They don't know you're here with us, so you hide in the closet. When they show up, we'll hear whatever their dumb story is about where they were, we'll pretend to believe them, and just when they think they got away with it, you jump out. Yeah, that's pretty good. (..)2016 TvShow: The Big Bang Theory Title: The Solder Excursion Diversion Season: 9 Episode 19