User`s guide

E-Prime User’s Guide
Chapter 3: Critical Timing
Page 110
With the changes in the TrialList and the Probe display, the experiment can now present the
Probe display for a range of durations. It is critical to run the experiment and analyze the
presentation data, and verify that the timing precision is what was expected. The following table
shows the first ten trials of the experiment, with the mean and SD calculated for the entire set of
24 trials.
TimingParadigm3 Time Audit Data (ms)
Fixation Probe Mask
Trial Onset
Delay
Onset
Time
Onset
Delay
Onset
Time
Onset
Delay
Onset
Time
Fixation-
Probe
Probe-
Mask
Probe
Duration
1 10 4410 8 4909 10 4942 499 33 23
2 13 7951 7 8449 10 8466 498 17 7
3 10 11175 8 11674 10 11724 499 50 40
4 14 14283 8 14782 10 14832 499 50 40
5 18 17359 7 17857 10 17890 498 33 23
6 4 20666 8 21165 10 21182 499 17 7
7 10 23775 7 24273 10 24290 498 17 7
8 12 26850 7 27348 10 27365 498 17 7
9 12 30108 7 30606 10 30656 498 50 40
10 8 32784 7 33282 11 33316 498 34 23
... ... ... ... ... ... ... ... ... ...
Mean 10.38 7.67 9.96 498.67 33.29 23.33
SD 4.64 0.47 0.45 0.47 13.43 13.47
In checking the reaction times, first verify that the Fixation-Probe duration (third to last column)
was as expected (e.g., 16.62ms/cycle * 30 cycles = 498.6ms). The observed mean was 498.67,
with a standard deviation of less than half of one millisecond. The duration of the Probe to Mask
time was to range from 17-50ms, and the expected values of 17, 33 and 50ms are present. The
average of the durations was 33.29ms, which is in close agreement with the expected time of