The stimuli were programmed on a Mac Pro computer (Mac Pro 3.1, Quad-Core Intel Xeon 2.8 GHz) using Matlab Version R2009b and Psychtoolbox [57], [58], and displayed using a Mitsubishi Electric colour data projector (Model XD400U) back-projected onto large (1.48 m wide by 1.20 m high) screen mounted on the lab wall.