he leader-member exchange theory was developed in several phases, firstly relying on the notion of role making, then on those of social exchange, reciprocity, and equity (Deluga, 1994). This theory entails that leaders cast role expectations on their followers and provide tangible and intangible rewards if these expectations are met. Similarly, followers also hold expectations from their leaders regarding their treatment and the rewards given if leaders’ expectations are met (Wang, Law, Hackett, Wang, & Chen, 2005). Therefore, followers are not considered passive role holders but they accept or reject and renegotiate the role that the leaders prescribed. In other words, there is a reciprocal process, a dyadic exchange, in which each of the parties brings different resources to be exchanged. Over time, the quality of a dyadic exchange changes, calling for role negotiations (Wang, Law, Hackett, Wang, & Chen, 2005).
Previous empirical research & Study Hypotheses
Edmondson (2004) argues that leader’s behaviour is one of psychological safety’s antecedents, positing that leader behaviour is influencing team psychological safety by creating salient beliefs among followers regarding the way that the leader will use power and how this may affect a follower. As well, a meta-analytic review of psychological safety found leadership to influence the team psychological safety by shaping the work environment (Frazier, Fainshmidt, Klinger, Pezeshkan, & Vracheva, 2017).
In a cross-sectional study on 489 health care workers from 28 nursery teams, Raes et al. (2013) investigated how team learning behaviour is influenced by the transformational leadership and laissez-faire leadership. The results showed that team learning behaviour was better predicted by transformational leadership, due to transformational leadership being primarly related to psychological safety while it is not the case for laissez-faire leadership (Raes, Lismont, Decupyer, & van den Bossche, 2013). On the other hand, a study on organisational learning analysing teams 44 whtin community clinics in Israel concluded that transactional leadership is negatively associated with learning behaviours (Amitay, Popper, & Lipshitz, 2005). Even though the authors of the study do not link directly this correlation with the team psychological safety, they posit that obtaining valid information for learning requires psychologically safe environments that discourage the usage of defensive routines (Amitay, Popper, & Lipshitz, 2005).

H1: Transformational leadership is positively related to psychological safety.
H2: Transactional leadership is negatively related to psychological safety.
In a study analysing more than 160 leader-follower dyads, Wang et al. (2005) found evidence suggesting that LMX mediates the relationship between transformational leadership and performance (more specifically, task performance and organisational citizenship behaviour). The study concluded that the behaviours of the transf