Lohan, K. S., Pitsch, K., Rohlfing, K., Fischer, K., Saunders, J., Lehmann, H., Nehaniv, C., &; Wrede, B. (2011). Contingency allows the robot to spot the tutor and to learn from interaction. 2011 IEEE International Conference on Development and Learning (ICDL 2011), 1–8.https://doi.org/10.1109/devlrn.2011.6037341