The paper presents a model where the self esteem and the self determination mechanisms are explicitly modelled in order to explain how they affect the intrinsic motivation and its impact on individual choices. The aim is to reconcile different explanations (and consequences) of the motivation crowding theory in a unique theoretical framework where the locus of control is introduced in a one period maximisation problem and the intrinsic motivation is assumed as an exogenous psychological attitude. The analysis is based on the different effect of the self esteem mechanism on intrinsic motivation input oriented or output oriented. Results show that crowding out of intrinsic motivation depends on the self determination sensitivity and the individual belief about one’s own self
