The Definitive Book of Body Language

The Power Is in Your Hands

given them an order to move the item and may begin to feel

antagonistic towards you, depending on your relationship with

him or the position you have with him in a work environment.

Turning your palm from facing

upwards to facing downwards completely

alters how others perceive you.

For example, if the other person was someone of equal status,
he might resist a Palm-Down request and would be more likely
to comply if you'd used the Palm-Up position. If the person is
your subordinate, the Palm-Down gesture is seen as acceptable
because you have the authority to use it.
The Nazi salute had the palm facing directly down and was
the symbol of power and tyranny during the Third Reich. If
Adolf Hitler had used his salute in the Palm-Up position no
one would have taken him seriously - they would have
laughed.

Adolf Hitler using one of history's most notable Palm-Down signals