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larissa
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Join Date: Sep 2013
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Correct Response Based on Previous Event, Posted September 3rd, 2013 #1
I am creating an experiment with the following structure:

1) cue for 500 ms
2) image of face for 150 ms
3) participant must categorize face as either thatcherized or normal by pressing a key
4) feedback to tell the participant if they were correct or not

The problem I am having is that I cannot figure out how to have the face event end after 150 ms, but also have a correct response and feedback.

In order to limit the face to 150 ms, I will need an event that is simply blank screen for the time between 150 ms and when the participant responds. But whether their response is correct or not is based on the face presented in event 2, not event 3. So I need a way to define a correct response based on an event other than the one in which the participant responds.

I am using a stimulus list to present the faces. Anyone know how to do what I'm asking?

The experiment is attached. The version I am attaching is in superlab 4, though I just updated to 5, so if there are new features to help me with my problem, I can use 5 instead.
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File Type: sl4 thatcher.sl4 (74.2 KB, 13 views)
Last edited by larissa; September 3rd, 2013 at 11:30 AM.. Reason: forgot to attach exp
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MonikaT
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Join Date: Mar 2008
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Posted September 4th, 2013 #2
Attached is a small demo experiment. In the experiment there are two stimulus lists. One list has pictures, and the other list has text.

SuperLab pairs the items of the stimulus lists, this means that even though we randomize the trials, the "owl" picture is always paired with the "owl" text. Therefore, for your experiment you can collect the response at the text event instead of the picture event. Since you will not want to display the text event, you can change the font to white, or display the text somewhere off the screen.

Also, under the Stimulus List Editor you will see a stimulus list named "names PAIRED with pictures." Within this list look at the Code Values tab, here you will see code values have been attached.

Under the Event Editor, then the Correct Response tab, within the event "practice trials - get response," there are correct responses defined. Also, look at the Feedback tab for the same event to see how it is set up.

Please note, randomization under the Trial Editor should be checked off. The only randomization setting for this experiment is the one in the Block Editor.
Attached Files
File Type: zip demo_thatcher.zip (80.9 KB, 41 views)
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correct response, feedback, previous event
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