Learning and adaptability (and thus the ability of being co-operative) are important features of decision & control systems. This paper investigates decision making and control concepts that enable human beings and artificial beings to interact and co-operate in real time in a dynamic and reliable way. It examines the aspects of being co-operative and substitutable in the context of: (i) co-operative driving by driverless vehicles; and (ii) computer game play scenarios for collaborative and social interactions.