The size-weight illusion in team lifting

The purpose of these studies was to examine whether or not there is a size-weight illusion when participants lift containers as a team. In Experiment 1, teams of participants lifted a set of 16 containers that varied in mass and size and reported their perceptions of heaviness and volume. In Experiment 2, participants lifted the same containers individually. A size-weight illusion was demonstrated in each experiment: Reports of perceived heaviness decreased substantially as the volumes of the containers increased for both styles of lifting. However, both the magnitude of the illusion and mean perceived heaviness were greater in the team lift. Actual or potential applications of this research include the development of safe lifting guidelines for team lifting.