Cooperative learning techniques in teaching activities are becoming increasingly popular. Many studies have documented the benefits of these techniques, but fewer have analysed the factors affecting students' achievement. One of those factors could be the student's proactivity, since cooperative techniques require active involvement of students. Proactivity or proactive behaviour relates to pioneering behaviour, initiative taken to exploit new opportunities, and a leading attitude. This study analyses the influence of several aspects related to students' proactivity on knowledge construction in the context of cooperative learning. The aspects included in the proactivity framework are the student's creativity, locus of control, self-effectiveness, and motivation towards cooperative learning. These variables and their potential effect on knowledge construction in cooperative experiences are discussed. The resulting hypotheses are tested with data from students who participated in a jigsaw, and the results show the positive impact of the internal locus of control and self-efficacy, along with the fact that the student is attending the course for the first time.