Well, without knowing what you're saying and what tone of voice you're using, it is impossible to know if he is trying to manipulate you. However, I think it is just possible that what you're doing is shaming him, because putting the head down and making depressed body movements sounds like he is exhibiting shame.
Instead of scolding, maybe you could try educating or instructing him. Try to always remember that he is just 6 years old and cannot always remember the right thing to do for every situation. Also, he simply does not have the self-control that adults or other, older children have, so he's going to need reminding and repetition in order to get certain behaviors right.
Getting angry at him for being a young child with limited attention span and limited memory and limited social skills, is like getting mad at him for his hair color or his height -- in other words, if you get mad at him for things he doesn't have any control over, then you are setting up an impossible situation for him. That's going to make him feel like a failure, and trust me -- you don't want that.
Remember...as the parent...the worse he feels about himself, the less he's going to feel like trying to do better. Give him smaller, less complex tasks and more basic expectations with more reminders, and see if that does not improve his behavior. I think you will find that the more things he masters, the more things he knows he can do right, the better he will feel about himself, and the less he will act out and perhaps even TRY TO GET NEGATIVE ATTENTION.
Make sure you give him lots of positive attention for the things he does right...and just postive, loving attention just because he's your son and you love him. It's really important that kids know they are loved just because they're your kids. That's the greatest self-esteem of all, and there's nothing on earth that can replace that kind of feeling comfortable with yourself, if that feeling is lacking.
Peace,
Syl