An energy absorbing device for a seat containing an occupant includes a seat frame with legs, a seat pan, and a back member. Attached to the seat is an energy absorbing device fixed to the back member of the seat frame. The energy absorbing device includes an engagement portion fixing the energy absorbing device to the seat frame and an energy absorbing extension having a fixed end integral with the engagement portion, and a protruding end extending toward the seat pan. The seat has a seat belt for the occupant and the belt is attached to a belt support device which extends parallel to the energy absorbing extension. When the occupant is using the seatbelt and the seat undergoes lateral forces, the energy absorbing extension undergoes deformation, and when the occupant is not using the seatbelt and the seat undergoes lateral forces, the energy absorbing extension does not undergo deformation.