Random Selection

Hi all,

I’m running a vignette study in which there are 32 different vignettes. However, I want each participant to see only 1 vignette. I currently have all of the vignettes under one block (“Vignettes”), and 4 separate trials (“Vignette 1,” “Vignette 2,” “Vignette 3,” “Vignette 4”), with 8 individual vignettes in each trial. How can I program the randomization so that each participant only sees one vignette?

Thanks a lot!

Do you mean one vignette per trial? So a total of four vignettes?

Ah, sorry for being unclear! I mean one vignette total per participant. The vignettes themselves don’t necessarily have to be placed in separate blocks, I just did it that way to keep myself organized while entering them.

I would recommend putting all your trials in one block, then you can randomize under the Block level. The next step is to create an Expression under the Trial Editor. Under the When to Run tab, click on the New button. Here you will select “Number of Times This Trial Has been Presented” is Less then 1 times.

Worked perfectly! Thank you!

One other question – does anyone know if Superlab will accept free-response (e.g., block text) answers? I want people to write short paragraphs after viewing a stimulus.


Yes, if you use the Keyboard String-Input option under Participant Input you will be able have participants type in short paragraphs.