Marina Bloj, Vision Sciences Research Group, Division of Optometry, University of Bradford

Brendan Barrett, Vision Sciences Research Group, Division of Optometry, University of Bradford.

Innes Cuthill, School of Biology, Bristol University

Suzanne McKee, Smith-Kettlewell Eye Research Institute, San Francisco, USA

Xavier Otazu, Universitat Autonoma de Barcelona

Laurie Wilcox, Centre for Vision Research, York University, Canada

Alex Wade, University of York.

Andrew Welchman, School of Psychology, University of Birmingham