The EU-funded ‘Psychological game theory and Bayesian rationality’ (Psychological GAMES) project sought to study peoples’ reasoning processes in psychological games. The approach took into account epistemic analysis in the literature offered by the type space approach introduced by Harsanyi (1967–1968) and the Bayesian state space approach introduced by Aumann (1976). Only the first includes tools for the development of theory in psychological games and so the project focused on study of the Bayesian foundations for insight into rationalisability and correlated equilibria – crucial solution concepts for strategic form games. Psychological GAMES set its sights on being able to contribute to the theory of extensive form psychological games assuming that players update their beliefs during the game. Games where the payoffs are dependent on motivation of individual players as well as expectations others have about their own behaviour and beliefs others have about everyone else's expectations have proven a useful tool for studying emotions. Strong feelings, which include guilt and reciprocity, are considered important in relation to belief hierarchies about players’ behaviours. This implies a strong link with epistemic game theory, which delves into the reasoning process of players. A paper was prepared advancing unification of various epistemic models applicable to psychological games and employed in the study of belief hierarchies. Other papers were also submitted for publication and a number of working papers are being further developed for future submissions. Project efforts contributed to clarifying certain issues that have engendered much discussion among game theorists and epistemic game theorists in particular. New insights have thus been offered for psychological game theory, rendering the project a relevant initiative for the particular scientific community. during the course of the project the lead researcher co-founded EpiCenter. Focusing on the study of epistemic game theory, this research group actively participates in the organisation of several events, one of which to date include an international conference.