maybe you've already figured out your solution maybe not. here's what i'd do.<div><br></div><div>i would have a List1 with two procedures: Target and NonTarget. set List1 to random.</div><div>* the Target procedure would have a List2 with two rows and one added column, WavFile. WavFile would be filled in with "[Wav]" to pull from a column by that name in a nested list. on one row you would nest the list TargetWavs (unless there were only ever a single target wav, in which case you wouldn't need to fool with a nested list), and on the other row you would nest the list NonTargetWavs. fill NonTargetWavs with all the nontarget.wav filenames under a column named Wav.</div>
<div>* the NonTarget procedure would have a List3 with one added column, WavFile. again, if there's only a single nontarget.wav (apple.wav) you might just enter that by hand in the column, WavFile. otherwise, nest your NonTargetWavs list.</div>
<div>adjust the weighting in List1 or in List3 to determine how many nontargets are presented between each target presentation.</div><div><br></div><div>does that make sense?</div><div><br></div><div><br><div class="gmail_quote">
On Fri, Jul 15, 2011 at 10:18 PM, Mark A <span dir="ltr"><<a href="mailto:markbfm@gmail.com">markbfm@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Dear E-Prime group,<br>
I am fairly new to E-Prime, but thus far have found online discussions<br>
within the group, as well as PST instructions and examples that have<br>
allowed me to program everything required, with one exception. The<br>
experimental task is simple: A participant listens to a series of<br>
words and presses a button whenever a particular word is heard (i.e.,<br>
the target word, "apple" in the example below). The target word is<br>
presented 4 times.<br>
<br>
My problem is this: I wish to present a series of stimuli (.wav files)<br>
randomly, with the restriction that I do not want "Target" files to be<br>
presented consecutively. Rather, I want them to be separated by at<br>
least one distractor (or non-target).<br>
<br>
To illustrate, this is an excerpt from one of my lists:<br>
<br>
Weight Nested Procedure Sound Talker Target SoundDur<br>
1 MAppleTrial m1apple.wav m1 yes 422<br>
1 MAppleTrial f4apple.wav f4 yes 546<br>
1 MAppleTrial m1apple.wav m1 yes 422<br>
1 MAppleTrial f4apple.wav f4 yes 546<br>
1 MAppleTrial m2bear.wav m2 no 332<br>
1 MAppleTrial f3bin.wav f3 no 375<br>
1 MAppleTrial m3cat.wav m3 no 383<br>
1 MAppleTrial f2chalk.wav f2 no 586<br>
..... and so forth (there are 4 targets and 23 distractors).<br>
<br>
Currently, I have the list set to "Random", however, this does not<br>
guarantee that the Target files (top 4 rows) will not occur<br>
consecutively. I think that the solution will involve a conditional<br>
statement (perhaps using In line) comparing whether the previous file<br>
presented was a target, but I am unsure how to implement this.<br>
<br>
An additional consideration is what to do if there are only 2 cycles<br>
left, and the two files left are both target files. If this is very<br>
hard to avoid, I am willing to live with this, as it is unlikely to<br>
occur very often. Any tips or links to helpful discussions on similar<br>
topics will be very much appreciated.<br>
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