User`s guide

E-Prime User’s Guide
Chapter 3: Critical Timing
Page 102
3.4.2.3 Select a basic critical timing paradigm
There are five basic critical timing paradigms we will describe. The paradigms range in
complexity from being concerned about timing a single event, a sequence of events, long streams
of events, and streams of events synchronized to an external clock to facilitate concurrent
biological recording. These paradigms are available for download via the PST website at
http://www.pstnet.com. The paradigms are:
Timing Paradigm 1: Single stimulus event to response timing
The goal of this paradigm is to present one stimulus per trial and precisely record the time interval
from the beginning to the end of the stimulus, or the time from the beginning of the stimulus to the
response. All other events are not time critical. An example would be to present a picture, word,
or sound, and wait either for a given duration or until the subject responds. This paradigm model
uses Event timing mode without the use of PreRelease.
Timing Paradigm 2: Critical sequence of events
A series of stimuli are presented and the onset delays between the stimuli must be precise, but
outside of the sequence, the timing is not critical. An example would be to present a sequence of
a fixation, probe, and mask, where the duration of each of the events is precise, the time of the
response is precise, and the response may occur during or after the stimulus event (e.g.,
response to the probe occurred while the mask display was presented). Subject input may alter
the timing (e.g., remove the stimulus when the subject responds). After the critical sequence of
events, the timing of the remaining events (e.g., feedback) and the time to choose the next
condition are not critical (e.g., delays of less than 100ms are not critical). This paradigm model
uses Event timing mode with PreRelease enabled on all objects except the last one of the
sequence. Durations for displays are set based on the refresh rate of the video mode.
Figure 13. Location of E-Prime housekeeping operations. Note, durations specified in labels will
vary with the complexity of the tasks being performed (e.g., amount of data being logged, flushing
of data to log file, number of list rows being reshuffled, etc.).