Does an automatic transmission down shift under hard acceleration?

I drive an 1997 honda prelude and when I am on the free way at about 50 or 60 mph, I should be on my 4th and last gear, but when i floor it, rpm would click and keep rising until I ease off the gas a bit, did the gear just down shifted to 3rd gear? and is this bad for the car to floor the gas pedal like that?