Abstract
This paper reports on research into patterns of social interaction associated with metacognitive
activity in senior secondary school mathematics classrooms. Unsuccessful collaborative
problem solving sessions were characterised by students' poor metacognitive decisions
exacerbated by lack of critical engagement with each other's thinking, while successful
outcomes were favoured if students challenged and discarded unhelpful ideas and actively
endorsed useful strategies. The findings have practical significance for implementation of new
mathematics curriculum policies that emphasise problem solving, mathematical reasoning, and
communication.