Patting or Petting?

Are we talking about for humans or for animals? Well, regardless, I think that petting, or rubbing is more of a true sign of affection. I worked in the medical field where we frequently comforted patients. We were taught to rub their hand or arm to comfort them instead of patting. The reason for this is from a psychological standpoint, to touch and remove the touch repeatedly, is somewhat like giving something only to take it away. When I give a hug, I rub the person's back. I try to maintain the contact as long as it is appropriate.