Abstract: The seat cushion of a seat can be tilted about its longitudinal center axis for generating a tilting movement of the pelvis of a seat occupant. For generating the tilting movement, an adjusting element is provided in each of the right and the left area of the seat cushion. The adjusting elements interact to cause an opposite adjusting movement in the vertical direction, whereby the tilting movement of the pelvis is achieved. The adjusting elements are constructed, for example, as liquid-filled rolling bellows, in which case a sliding vane rotary pump changes the volume of the two adjusting elements in a diametrically opposed manner.