i.e. some body parts, such as the hands, may afford the formation of far stronger associations than other parts that are less accessible to vision (e.g. the shoulders and back; faces, if it were not for mirrors). But there is no reason to believe that a strong visuo-motor association is a necessary prerequisite for the actions and/or expressions produced by a body part to be intelligible for an observer. If that were the case, it would mean that our ancestors living in cultures without mirrors must have been unable to understand facial expressions.