Scaffolding peer-assessment skills: Risk of interference with learning domain-specific skills?

Giving students complex learning tasks combined with peer-assessment tasks can impose a high cognitive load. Scaffolding has proven to reduce cognitive load during learning and improve accuracy on domain-specific tasks. This study investigated whether scaffolding has a similar, positive effect on the learning of peer-assessment tasks. We hypothesised that: (1) domain-specific scaffolding improves domain-specific accuracy and reduces time on task and perceived mental effort, and (2) peer-assessment scaffolding improves peer-assessment accuracy and reduces time on task and perceived mental effort. Additionally, we explored whether there was an interaction between domain-specific and peer-assessment scaffolding. In a 2x2 experiment with the factors domain-specific scaffolding (present, absent) and peer-assessment scaffolding (present, absent), 236 secondary school students assessed the performance of fictitious peers in an electronic learning environment. We found that domain-specific accuracy indeed improved with domain-specific scaffolding, confirming our first hypothesis. Our tests of the second hypothesis, however, revealed surprising results: peer-assessment scaffolding significantly increased accuracy and mental effort during learning, it had no effect on peer-assessment accuracy at the test and led to reduced domain-specific accuracy, even when combined with domain-specific scaffolding. These results suggest that scaffolding students' peer assessment before they have mastered the task at hand can have disturbing effects on students' ability to learn from the task.