An occupant detection system is configured to classify an object that resides on a seat of a vehicle. The system includes a first bladder, a second bladder, and a differential pressure sensor. The first bladder is configured to be disposed in a central area of a seat. The second bladder is configured to be disposed in a peripheral area of the seat. The differential pressure sensor is fluidicly coupled to the first bladder and the second bladder in a manner effective to determine a pressure difference between a first pressure of the first bladder and a second pressure of the second bladder. In one configuration, the first bladder and the second bladder are configured so the pressure difference when a person sits on the seat is greater than the pressure difference when a child-seat occupies the seat.