Peer review is a reciprocal process whereby students produce feedback reviews on the work of peers and receive feedback reviews from peers on their own work. Prior research has primarily examined the learning benefits that result from the receipt of feedback reviews, with few studies specifically exploring the merits of producing feedback reviews or the learning mechanisms that this activates. Using accounts of their experiences of peer review, this study illuminates students' perceptions of the different learning benefits resulting from feedback receipt and feedback production, and, importantly, it provides insight into the cognitive processes that are activated when students construct feedback reviews. The findings show that producing feedback reviews engages students in multiple acts of evaluative judgement, both about the work of peers, and, through a reflective process, about their own work; that it involves them in both invoking and applying criteria to explain those judgements; and that it shifts control of feedback processes into students' hands, a shift that can reduce their need for external feedback. The theoretical and practical implications of these findings are discussed. It is argued that the capacity to produce quality feedback is a fundamental graduate skill, and, as such, it should receive much greater attention in higher education curricula.