This study investigated how students' social identity and approach to studying influence their general attitude towards group work and their way of working in a particular collaborative source-based writing assignment. The respondents were 53 upper secondary school students who filled out a survey about their social identity, approach to studying, general group work attitude and ways to work on an assignment. The findings showed that students' social identity (popular, lonely, leader, follower) and their approach to studying (deep, surface, strategic) played out both in their general group work attitude and their work in the collaborative source-based writing assignment, but not always in a matching way. The findings underline the importance of acknowledging students' positioning towards both social and learning dynamics in collaborative work.