Hello, I am in the process of learning about superlab. I am trying to programme an emotionally modified exogenous cueing task that involves presenting a fixation cross in the centre of the screenflanked by two white rectangular frames. A word from a stimulus list will then appear on this screen either in the frame to the left or the right of the fixation, a probe will then appear in the same or opposite frame.
The problem I am having at the moment is how I actually input this so that I have a screen with a central fixation cross with two white frames either side.
My second problem is then how to get my stimulus words to appear in the white frames?
If you want the fixation cross and the two white frames to appear at the same time, you can create a single image file. Your trial would then consist of two events: the first uses a stimulus of type Picture File and the second uses a stimulus of type Text and uses a stimulus list.
It will take a little bit of trial and error to make sure that the white frames are large enough to fit the words and to position the words, but it’s pretty straightforward otherwise.
It depends on whether you are on a Mac or Windows. There are lots of nifty little shareware and freeware software for creating simple things like a frame. Feel free to post a note on which one(s) you find and like.
I recently completed the tutorial in SuperLab, and I am trying to become familiar with how to use this software. I also need to create an exogenous cueing task, which basically boils down to:
The presentation of a black screen. In the middle of the black screen, there is a white fixation cross flanked by two white rectangles. Per advice given in this discussion, I have created this as a single image file, but this is as far as I’ve gotten.
After 250ms, a picture should fill either the left or the right rectangle. The fixation cross and the other rectangle should remain on the screen. The picture will fill one rectangle for another 250ms.
The picture will then disappear, leaving the beginning image (white fixation cross flanked by two white rectangles). However, one of the rectangles will now contain a black target square. The participant’s job is to use the keyboard to indicate whether that square appeared in the left or right rectangle.
I’m not sure of the easiest way to make this happen in SuperLab. I thought that perhaps I might have to create every single stimulus within the event as a single image file, but I really am lost here. Can anyone help me?
1. The presentation of a black screen. In the middle of the black screen, there is a white fixation cross flanked by two white rectangles. Per advice given in this discussion, I have created this as a single image file, but this is as far as I’ve gotten.?
[SIZE=“2”]Create one picture file that contains the fixation cross and the two white triangles.[/SIZE]
2. After 250ms, a picture should fill either the left or the right rectangle. The fixation cross and the other rectangle should remain on the screen. The picture will fill one rectangle for another 250ms.
[SIZE=“2”]Use a stimulus list and a trial variable for screen location. This will randomize the positions on screen.
[/SIZE] 3. The picture will then disappear, leaving the beginning image (white fixation cross flanked by two white rectangles). However, one of the rectangles will now contain a black target square. The participant’s job is to use the keyboard to indicate whether that square appeared in the left or right rectangle.
[SIZE=“2”]Are the positions of the picture and the black target square paired? Or, should they be completely random?[/SIZE]
In response to point 2: I attempted to create a stimulus list of pictures. However, I am unsure of how to keep the fixation cross and white rectangles on the screen. That is, I need the picture to appear and fill one of the rectangles, but the fixation cross and other unfilled white rectangle need to remain on the screen. Also, I’m unsure of how to make the picture appear in the exact spot as the rectangle. My test picture appeared in the center of the screen.
In response to the question you presented to point 3: The position of the picture and target square need to be set so that the target square appears in the same rectangle as the picture in 75% of the toatl 240 trials (so 180 trials). The remaining 25% (60 trials) should appear in the opposite rectangle as the picture.
To keep both the fixation point and the white triangle on the screen simultaneously, the second event needs to have Erase screen before presenting stimulus checked off.
In the Event Editor, under the Settings tab, there is another tab called Position. Here you are able to specify the position of your image.
This can be done with the caveat that the same set of pictures will be presented on one side. In other words, some pictures will always appear on the right and some will always appear on the left. Their order of presentation can still be randomized. If you can live with this caveat, you can achieve true randomization of the target position. To start:
Split your pictures into two stimulus lists, with correspondingly two events.
Link each event to its own trial, e.g "Trial right" and "Trial left".
Create a block with randomization enabled, then link the two trials to this block.
To display the target, we also need to create two trial variables and two events:
To display a target on the left side of the screen 25% of the time, create a trial variable that contains four levels: three positions to the right and one to the left. In the trial variable editor's [B]Level Selection[/B] tab, select [B]Random With No Replacement[/B].
Create the event for the left-hand side target. In the Event Editor's[B] Stimulus[/B] tab, click on[B] Settings[/B]. In the dialog that appears, click on the [B]Position[/B] tab and set the position to use the trial variable that you have just created.
Back in the main window, link the newly created event to "Trial left".
