Thread Tools  
ofree
Junior Member
 
Join Date: Apr 2017
ofree is on a distinguished road Posts: 3
Need help to create RSVP experiment, Posted April 14th, 2017 #1
Hello! I am very new to Superb and trying to conduct an experiment on Attentional Blink using RSVP. I already started to combine the file, but I wonder if there is somewhere I can find a template for it?
The experiment is the following - each trial started with a 1,780-ms fixation cross (0.5 0.5), followed by a rapid serial stream of 15 or 19 letters (0.8 0.8). Each letter was randomly drawn from the alphabet (except B, I, O, Q, and S) and presented for 50 ms, followed by a 34-ms blank. On each trial, two letters is replaced with a number, randomly drawn from the set 29. The temporal distance between the first (T1) and second (T2) number could be short (336 ms), medium (500ms) or long (672 ms). T2 and is presented at temporal position 35 from the end of the stream.

Thanks!
Reply With Quote
Arman
Support
 
Join Date: Jun 2016
Arman is on a distinguished road Posts: 148
Posted April 14th, 2017 #2
Welcome to the forum.

Unfortunately, I do not think there is such a template yet. However, if you have a specific question about achieving a certain task with SuperLab, I will be glad to help.
Reply With Quote
ofree
Junior Member
 
Join Date: Apr 2017
ofree is on a distinguished road Posts: 3
Posted April 30th, 2017 #3
Hello Arman, thank you for your response.
My first issue is how to combine numbers and letters in one string so 2 numbers would be chosen randomly from the "number" list and replace 2 letters with a specific temporal distance between them.
Reply With Quote
Arman
Support
 
Join Date: Jun 2016
Arman is on a distinguished road Posts: 148
Posted May 1st, 2017 #4
Try using a stimulus list to present your letters and control their location with a manual trial variable and rules. After the letters are presented, use this same trial variable to randomly select where the numbers will be presented (and therefore which letters will be replaced).

To replace a letter with a number, you must erase the the letter with an eraser event, which is just a small blank image that is the same color as the background. Then, present the number.

To vary the temporal distance between the numbers, create a blank text event that utilizes its own time limit trial variable.
Reply With Quote
Arman
Support
 
Join Date: Jun 2016
Arman is on a distinguished road Posts: 148
Posted May 1st, 2017 #5
I have drafted and attached such an experiment that uses 7 letters rather than 15 or 19.
Attached Files
File Type: zip replaceLetters.zip (5.8 KB, 2 views)
Reply With Quote
ofree
Junior Member
 
Join Date: Apr 2017
ofree is on a distinguished road Posts: 3
Posted May 2nd, 2017 #6
Arman, thanks, but I may not explained myself clear. I am making an Attentional Blink experiment using RSVP, not presenting them all at the same time. The letters in the string should be replaced by 2 numbers in each trial.
Reply With Quote
Arman
Support
 
Join Date: Jun 2016
Arman is on a distinguished road Posts: 148
Posted May 3rd, 2017 #7
I see. Take a look at the attached experiment.

The trial is set to present 17 letters. However, its rules present numbers at two different temporal positions, giving a total of 19 presentations.

There's a parameter, Temporal Distance Type, that determines if the distance is short, medium, or long. It is set randomly, after which the trial rules will present T2 accordingly; e.g. T1 is presented as the 6th item and T2 is presented either as the 10th, 12th, or 14th item depending on the temporal distance type.

The temporal distances should be divisible by the duration of each item+blank presentation. I hope this will be a helpful starting point.
Attached Files
File Type: sl5 serialNumLett.sl5 (6.8 KB, 5 views)
Reply With Quote
Thread Tools
Posting Rules
Forum Jump:
Copyright Cedrus Corporation, 1991-2014.
All times are GMT -7. The time now is 03:46 PM.