Or can they be moved ... at different rates ... ?
I saw a power glider (maybe an SF-28 or an RF-5) where the ailerons moved with a different rate.
The reason was an effect whose German name translates to "negative turn effect", but I don't know the correct English word for it:
If you operate the ailerons to the right, the ailerons work in a way that the left wing produces more lift and therefore more air resistance than the right one.
Therefore operating the ailerons to the right will also have a similar effect as operating the rudder to the left. (For this reason the rudder has to be operated to the right together with the ailerons to compensate that effect.)
The power glider I have seen was built in a way that the left aileron only did a much smaller motion then the right one when putting the stick to the right. By doing so, the right aileron worked like an air brake so the air resistance of both wings was nearly equal and there was no "negative turn effect".
Finally, are there any aeroplanes on which they can be moved in the same direction?
There are airplanes that use "flapperons":
This means that the same part is used as flap and as aileron.
Being used as flaps, the flapperons move in the same direction; being used as ailerons, they move in different directions.