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We are designing a cueing experiment with a visual search array. After presenting the fixation stimulus and the location cues, there is an ISI of 250 ms before presentation of the search array (which varies in number from 5 to 12). We have noticed when we actually run the file, the ISI is not 250 ms, but closer to 1000 ms. I realize that this is likely due to issues of drawing the array, but I need to overcome this and have an ISI of 250 ms. Any suggestions? I have attached the file.
Can someone help me fix this issue of directRT (or perhaps it is my hardware) add at least 700 msec to the ISIs of my trials? I need to have an ISI of ONLY 250 msec. This is what we enter in the file, but this is not what we get -- we get over a 1000 msec ISI.
WHAT IS CAUSING THIS? HOW DO WE FIX THIS? HOW DO WE ENSURE THAT WE GET THE ISI TIMING THAT WE INPUT?
HELP -- URGENT!!!!
Scott
[QUOTE=sadler;17667]We are designing a cueing experiment with a visual search array. After presenting the fixation stimulus and the location cues, there is an ISI of 250 ms before presentation of the search array (which varies in number from 5 to 12). We have noticed when we actually run the file, the ISI is not 250 ms, but closer to 1000 ms. I realize that this is likely due to issues of drawing the array, but I need to overcome this and have an ISI of 250 ms. Any suggestions? I have attached the file.[/QUOTE]