Figure 1.

Abridged examples of the trial definition (.DEF) file format and the trial order (.ORD) file format. Each trial named in the .ORD file must be defined in the .DEF file. For the first trial (“Ready”), “timing = −1 keyboard” means wait indefinitely for a keypress (the spacebar is the only allowable key) while displaying the text “Ready …” at position (0,0.2) and height 0.15. The “Fixation” trial involves displaying the image file cross.jpg in the center of the screen for 15 s, with extra frames inserted or removed there if cumulative timing errors have accumulated. The “Left.04” stimulus displays the image file L4.jpg in the center of the screen for exactly 1.5 s.