The M-Ecolab was developed to provide motivational scaffolding via an on-screen character whose demeanour defended on modelling the learner’s motivational state at interaction time. Motivational modelling was based on three variables: effort, independence and the confidence. A classroom evalu-ation was conducted to illustrate the effects of motivational scaffolding. Students had an eighty minute interaction with the M-Ecolab, divided into two sessions. The results suggested a positive effect of the motivational scaffolding, particularly for initially de-motivated students who demonstrated higher learning gains. We found that these students followed the suggestions of the on-screen character which delivered personalized feedback. They behaved in a way that was conducive to learning by being challenge-seekers and displaying an inclination to exert more effort. This paper gives a detailed account of the methodology and findings that resulted from the empirical evaluation.