They are spoilers, designed to dump lift by goofing the airflow over that section of the wing. Spoilers generally don't work too well as speedbrakes. Of course there's the always the speed/alt energy link, but spoliers are better for increasing the descent rate...get down in a hurry, level off, THEN you can slow if needed.

Speedbrakes are more drag oriented, and for a heavy turbojet they need to be very large to do much. I think fighters can use speedbrakes due the whole drag = speed^2 thing.