[DMDX] Timing of mwc continued Dear Sir,    I just have some further questions related to call keyword. In the  following script (tick length = 16.65ms):       0 "Press Spacebar to begin"; 1 <% 60> "GO"/<% 39>/ m1## m2## mC## mW##; 999  d2 "Time Out" <% 12>/ ; 991  d2 "CORRECT" <% 12>/; 992  d2 "WRONG" <% 12>/; +1<% 12> g "fix_white"/ ~1 ~C*<% 36> g "noise1"/<% 36>/!; -2<% 12> g "fix_white"/ ~2 ~C*<% 36> g "noise2"/<% 36>/!; at which point the time out text 999 is called? I think it is called  right after the time-out point 1500ms set by the count-on asterisk,  so the total duration of one trial should be  12+36+20+(36+1)+(2+12+1)=120 ticks. However, DMDX told me there was a  16-ticks delay. This delay only disappeared after I set time-out=1200. The second question is DMDX also reported a delay of 5 ticks for the  instruction "Press Spacebar to begin" which varied from time to time.  This did not get improved by varying the time-out limit. Hongchuan -------------------------------------------- Hongchuan Zhang, Ph.D Center for Human Development University of California, San Diego AP&M Annex, 9500 Gilman Drive, 0115 La Jolla, CA, 92093-0115 Tel: (858) 534-2342 FAX: (858) 534-2344 hczhang@ucsd.edu