Yes, they are.    

Spoilers are

small, hinged plates on the top portion of wings. Spoilers can be used to slow

an aircraft, or to make an aircraft descend, if they are deployed on both

wings. Spoilers can also be used to generate a rolling motion for an aircraft,

if they are deployed on only one wing. 

 In aeronautics, a spoiler (sometimes called a lift spoiler or lift

dumper) is a device that intentionally reduces the lift component of an airfoil

in a controlled way.  

. No, they are not.