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rjt
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Join Date: Feb 2014
rjt is on a distinguished road Posts: 3
Hello,

I am trying to create an experiment where two words are presented on the screen. After 1000ms, one of the words (the target word) changes color (or becomes highlighted, or surrounded by a box, or something like that). The target word should sometimes be on the left and sometimes on the right.

The way I went about doing this was to have SuperLab draw from two lists, "targetlist" and "fillerlist", and have two text events immediately sequential to each other. These events use the two-level trial variable "ScreenPosition" to place each word on the left or the right. Then, after 1000ms, the process is repeated, but this time, the text event that outputs the word from "targetlist" is set to write in red. However, because ScreenPosition is random, sometimes the position of the two words flips. In order for this approach to work, I need SuperLab to be able to "remember" what the previous value of ScreenPosition was, which I don't think is possible.

So, is there another way to go about solving this problem? Thanks in advance for any ideas or suggestions.
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Hisham
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Join Date: Aug 2006
Location: San Pedro, CA
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Posted October 3rd, 2014 #2
It is possible to do it. Rather than having SuperLab 4 “remember” the last position, you can have it stuck at repeating the same sequence over and over again within a trial. To do so:
  • Edit your trial variable
  • In the Level Selection tab, set the option “Randomize levels before start of” to Each Trial
  • At the bottom of the dialog, the Randomize again option is turned on by default; turn it off
The attached experiment does what you asked for. There is an event called “no nothing event”; it’s only purpose is to use up the first location, i.e. the filler’s location. This is followed by an “underline” event that displays a red underline under the target text. (Note: on SuperLab for Windows, this might erase the target word, but you get the idea; the positioning is correct).
Attached Files
File Type: sl4 rjt experiment.sl4 (6.0 KB, 5 views)
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rjt
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Join Date: Feb 2014
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Posted October 3rd, 2014 #3
Hi Hisham,

Thanks, that worked a treat! I hadn't considered the possibility of randomizing just within the trial. The experiment works perfectly now!
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