In this chapter we provide first a basic introduction to Hilbert space modelling, and its applications outside typical quantum mechanics, for example in classical optics, and human cognition. We then present briefly our framework of human cognition model, which we have called, COM: classical optical modelling. Though our chapter is based on the background of and in the wake of quantum-like modelling in cognition, game theory, and different social science areas, our approach differs from the extant models since we follow the Hilbert space modelling in classical optics, with novel features like classical entanglement which can also be exploited in game theory. Hence, we aim to contribute in cognition as well as quantum-like modelling in game theory.