Crown Copyright © 2016 Published by Elsevier Inc. The attached document (embargoed until 25/08/2018) is an author produced version of a paper accepted for publication in Contemporary Educational Psychology uploaded in accordance with the publisher’s self- archiving policy. The final published version (version of record) is available online at http://dx.doi.org/10.1016/j.cedpsych.2016.08.003. Some minor differences between this version and the final published version may remain. We suggest you refer to the final published version should you wish to cite from it.