Sensor device for determining the deviation of the position of a head support of a motor vehicle seat from a target position, comprising - a capacitive proximity sensor that can be or is integrated into the head support, which has ∘ two transmitting electrodes (12, 13) arranged at a vertical distance from each other, and ∘ a mutual receiving electrode, and - a control unit, which is equipped for: ∘ actuating the transmitting electrodes (12, 13) for transmitting an alternating electrical field (F1, F2), ∘ determining a dimension (Δz, Δx) for the vertical and horizontal deviation of the head support position from a predetermined target position relative to the position of a head of a vehicle passenger from received electrical signals (E1, E2) recorded by the receiving electrode, said signals including information about the capacitance (C1, C2) formed between each of the transmitting electrodes (12, 13) and the receiving electrode, ∘ determining the dimension (Δz) for the vertical deviation of the head support position with the aid of a difference between the received signals (E1, E2) allocated to the two transmitting electrodes (12, 13) or respective parameters (C1, C2) derived therefrom, and ∘ determining the dimension (Δx) for the horizontal deviation of the head support position with the aid of a sum of the received signals (E1, E2) allocated to the two transmitting electrodes (12, 13) or respective parameters (C1, C2) derived therefrom. - a capacitive proximity sensor that can be or is integrated into the head support, which has ∘ two transmitting electrodes (12, 13) arranged at a vertical distance from each other, and ∘ a mutual receiving electrode, and ∘ two transmitting electrodes (12, 13) arranged at a vertical distance from each other, and ∘ a mutual receiving electrode, and - a control unit, which is equipped for: ∘ actuating the transmitting electrodes (12, 13) for transmitting an alternating electrical field (F1, F2), ∘ determining a dimension (Δz, Δx) for the vertical and horizontal deviation of the head support position from a predetermined target position relative to the position of a head of a vehicle passenger from received electrical signals (E1, E2) recorded by the receiving electrode, said signals including information about the capacitance (C1, C2) formed between each of the transmitting electrodes (12, 13) and the receiving electrode, ∘ determining the dimension (Δz) for the vertical deviation of the head support position with the aid of a difference between the received signals (E1, E2) allocated to the two transmitting electrodes (12, 13) or respective parameters (C1, C2) derived therefrom, and ∘ determining the dimension (Δx) for the horizontal deviation of the head support position with the aid of a sum of the received signals (E1, E2) allocated to the two transmitting electrodes (12, 13) or respective parameters (C1, C2) derived therefrom. ∘ actuating the transmitting electrodes (12, 13) for transmitting an alternating electrical field (F1, F2), ∘ determining a dimension (Δz, Δx) for the vertical and horizontal deviation of the head support position from a predetermined target position relative to the position of a head of a vehicle passenger from received electrical signals (E1, E2) recorded by the receiving electrode, said signals including information about the capacitance (C1, C2) formed between each of the transmitting electrodes (12, 13) and the receiving electrode, ∘ determining the dimension (Δz) for the vertical deviation of the head support position with the aid of a difference between the received signals (E1, E2) allocated to the two transmitting electrodes (12, 13) or respective parameters (C1, C2) derived therefrom, and ∘ determining the dimension (Δx) for the horizontal deviation of the head support position with the aid of a sum of the received signals (E1, E2) allocated to the two transmitting electrodes (12, 13) or respective parameters (C1, C2) derived therefrom.