Hargreaves and his Tavistock colleagues were particularly interested in selection, and only a few months after joining up, Hargreaves was experimenting with the use of Raven's Progressive Matrices as a way of screening out unsuitable recruits [REF].
Hargreaves also liaised with the United States Army and the Canadian Army, who he advised on the use of psychological staff when visiting North America in 1943 as Consultant to the Army [REF].