[open] how to randomize blocks?

vesna

Hello,

I recently started using OpenSesame and I couldn’t find the solution for my problem.

Is it possible to randomize blocks in OpenSesame? I made 4 block loops (each with trial sequence) and I want them to be presented in random order. I work with facial expressions and the idea is to present one emotion per block but not always in the same order.

Thank you in advance!

EDIT (by fladd): Moved to "OpenSesame" category.

eduard

Hi Vesna,

Welcome on the forum!

Yes, randomization is possible with Opensesame (it would be a very poor experiment builder if not). The scenario you describe sounds like a pretty standard case, where it should be enough to set the order field, in the top right corner of the loop element to random rather than sequential.

Does this make sense? Btw. If you wanna learn the basics of Opensesame, I recommend you have a look at the beginner's tutorial.

Good luck,

Eduard

andersony3k

I believe Vesna's question was about randomizing the order in which the blocks are presented (where each block includes its own loop of trials), not randomization within a loop of trials.

Art

Has this actually ever been implemented in Opensesame?

eduard

Hi,

Not that I know, but it is not very hard to implement. Just write your block loops in Opensesame, set their run if fields to never. Then, in an inline_script you can create a list with the block_names, randomize it and run one at a time with this command:

 items.execute(u'my_block')

Does that make sense?

Eudard

andersony3k

The solution (without having to write code) was given to me some time ago in another thread: https://forum.cogsci.nl/discussion/4041/feature-request-allow-each-row-within-a-loop-to-run-different-sequence#latest

Also, I've created a simple, working example (attached).

Block Randomization Example.zip