1. An attention detection system comprising: at least one first sensor device, located at a host wearer, for generating a host perspective signal relating to attention clues indicative of the attention of the host wearer to an observer; and at least one second sensor device, located at the observer, for generating an observer perspective signal relating to attention clues indicative of the attention of the observer to the host wearer; and a portable attention detector for receiving the host perspective and the observer perspective signals and for determining a situation of raised attention of said host wearer from said received host perspective signal and said received observer perspective signal.