The combination of learning by intrinsic moti- vation and social learning has been shown to improve the learner's performance and gain precision over a wider range of motor skills, with for instance the SGIM-D learning algorithm. Nevertheless, this bootstrapping a-priori depends on the demonstrations made by the teacher. We propose in this paper to examine this dependence: to what extend the quality of the demonstrations can influence the learning performance, and which are the characteristics of a good demonstrator. Results on a fishing experiment highlights the importance of the difficulty of the demonstrated tasks, as well as the structure of the actions demonstrated.