1. Children's ability to make transitive inferences: The importance of premise integration and structural complexity
2. Birney, O. P. and Halford, G. S. Methods for analysing complexity in reasoning tasks: Linksto fluid intelligence. Paper presented at the Fourth International Conference on Thinking. UK: University of Durham.
3. Birney, O. P. and Halford, G. S. Principles of relational complexity in cognitive task development. Paper presented at the Fifth Australasian Cognitive Science Conference. Australia: University of Melbourne.
4. Birney, O. P. and Halford, G. S. The psychometric properties of relational complexity in adult cognition. Poster presented at the XVI British Psychological Society Cognitive Section Conference. UK: The University of Essex.