User`s guide

E-Prime User’s Guide
Appendix C: Sample Experiments
Page A-46
The Nested attribute in the TrialList defines the List objects from which the exemplars will be
sampled in order to resolve the values for Word and NonWord in the Stim1 and Stim2 columns.
The colon syntax (e.g., [Word:0], [Word:1], etc.) directs E-Prime to sample a specific number of
times from the appropriate List. The colon syntax default value is 0, which samples one time from
the designated List. The integer value following the colon indicates the number of additional
samples from the List (e.g., [Word:1] would result in two exemplars being sampled from the List.
Change the stimulus
The value of the Stim1 and Stim2 Attributes may be changed by modifying the Nested lists
(WordList, NonWordList).
Populate Lists from text files
Rather than entering values directly into a List object, stimuli may be entered into tab-delimited
text files and read into the List at run-time. This is accomplished by setting the LoadMethod
property for the List object to “File”, and specifying the name of the text file as the Filename
property for the List object. The file must be in tab-delimited, ASCII file format, and should
contain the attribute header data (including the system attributes Weight, Procedure, and
Nested).
Basic Reaction Time: Extended Input
The NestingXRT experiment is a modification of the NestingRT experiment illustrating extended
input. A fixation is displayed, followed by two brief stimulus presentations (i.e., 500msec) and a
mask. Finally, the mask is cleared and a response is collected in response to whether or not the
stimuli were both words. The NestingXRT experiment illustrates the use of nested List objects
and the colon syntax to sample stimuli from more than one List during the same trial, and sample
multiple stimuli from the same List during a single trial. Refer to NestingRT (above) for a
description of nesting and the colon syntax. NestingXRT also illustrates the collection of input
extended over several objects (i.e., two stimulus presentations and a mask presentation).
The TrialList defines the variables to be used within the experiment as attributes, and the levels
for the attributes. The NestingXRT experiment uses the Stim1 and Stim2 attributes to display
words and nonwords simultaneously. The CorrectAnswer attribute is used to score the input
collected in response to the Stimulus display, and provide feedback via the Feedback object.